Dementia: Not an Inevitable Part of Aging

A recent survey revealed that nearly half of adults aged 40 years and older think they will likely develop dementia, such as Alzheimer’s disease.¹

The truth is dementia is not a normal or inevitable part of typical brain aging. It is also important to remember that as we get older, it is common to experience some cognitive decline with typical brain aging, such as subtle changes in memory, thinking, and  reasoning. For example, you might not immediately remember where you left your car keys, but you can find them when retracing your steps, or you can’t think of the name of a person you just met; however, you remember meeting them. These subtle changes can be frustrating and should not be bad enough to affect your daily life.

Modifiable Risk Factors and Alzheimer’s Disease and Related Dementias

Modifiable risk factors are the lifestyle and behaviors that can reduce or increase a person’s chances of developing a disease. For example, there are modifiable risk factors that could reduce your risk of Alzheimer’s disease and related dementias (ADRD), slow its progression, or increase your risk of ADRD. Most modifiable risk factors for ADRD are related to cardiovascular disease and other chronic health conditions. They include hypertension, not getting enough physical exercise, obesity, diabetes, depression, smoking, hearing loss, and binge drinking. Maintaining a healthy lifestyle and managing related chronic conditions is good for your overall physical health, facilitates and improves brain health, and may help decrease the risk of dementia or slow its progression.

Common Risk Factors Among Adults 45 Years and Older

A new CDC study examined how common these eight risk factors (hypertension, not getting enough physical exercise, obesity, diabetes, depression, smoking, hearing loss, and binge drinking) were among adults 45 years and older: ² 

• Nearly 50% had high blood pressure or did not meet the aerobic physical activity guideline.
• Adults with cognitive decline were more likely to report at least 4 factors (34%) than those without cognitive decline (13%).
• 34% of adults who reported cognitive decline—worsening confusion or memory loss in the previous year—had at least 4 risk factors compared with 13.1% of those without cognitive decline.
• 9% of adults with no risk factors reported cognitive decline while 25% of those with at least 4 risk factors reported cognitive decline.
• Several modifiable risk factors were more common among African American, Hispanic, and American Indian or Alaska Native populations than other races and ethnicities.

Older African Americans have twice the incidence and prevalence of ADRD and higher burdens of chronic disease, like hypertension, than non-Hispanic White Americans.³

Ways to Improve Your Brain Health

There is encouraging scientific news despite these risk factors: nearly 40% of all ADRD may be prevented or delayed.⁴ Since ADRD takes years to develop, there are opportunities to develop and maintain healthy lifestyle habits that could reduce your risk of ADRD or slow its progression. It is never too late to break old habits and start new ones.

This healthy lifestyle habits list consists of some things you can do and some things you should try to limit or avoid.

Things You Can Do: 

• Get Active and Maintain a Healthy Weight—Regular physical activity is important for good health and combined with a healthy diet can lead to a healthy weight.

• Manage Blood Sugar—Learn how to manage your blood sugar if you have diabetes.
• Prevent and Manage High Blood Pressure—Tens of millions of adults in the United States have high blood pressure, and many do not have it under control. Learn the facts.
• Prevent and Correct Hearing Loss—Make sure to talk to a hearing care professional to treat and manage hearing loss.
• Find Support—Depression is not just having “the blues” or the emotions we feel when grieving the loss of a loved one. It is a medical condition that can be treatable.

Things You Should Try to Limit or Avoid:

• Binge Drinking—If you drink, do so in moderation. Learn about alcohol use and your health.
• Smoking—Quitting smoking improves your health and reduces your risk of heart disease, cancer, lung disease, and other smoking-related illnesses.

To learn more, please visit https://www.cdc.gov/aging/publications/features/dementia-risk-reduction-june-2022/index.html.

There are four types of influenza viruses: A, B, C, and D. Influenza A and B viruses cause seasonal epidemics of disease in people (known as flu season) almost every winter in the United States. Influenza A viruses are the only influenza viruses known to cause flu pandemics (i.e., global epidemics of flu disease). A pandemic can occur when a new and different influenza A virus emerges that infects people, has the ability to spread efficiently among people, and against which people have little or no immunity. Influenza C virus infections generally cause mild illness and are not thought to cause human epidemics. Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.

Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes (H1 through H18 and N1 through N11, respectively). While more than 130 influenza A subtype combinations have been identified in nature, primarily from wild birds, there are potentially many more influenza A subtype combinations given the propensity for virus “reassortment.” Reassortment is a process by which influenza viruses swap gene segments. Reassortment can occur when two influenza viruses infect a host at the same time and swap genetic information. Current subtypes of influenza A viruses that routinely circulate in people include A(H1N1) and A(H3N2). Influenza A subtypes can be further broken down into different genetic “clades” and “sub-clades.” See the “Influenza Viruses” graphic below for a visual depiction of these classifications.

This graphic shows the two types of influenza viruses (A and B) that cause most human illness and that are responsible for flu seasons each year. Influenza A viruses are further classified into subtypes, while influenza B viruses are further classified into two lineages: B/Yamagata and B/Victoria. Both influenza A and B viruses can be further classified into clades and sub-clades (which are sometimes called groups and sub-groups.) Note that this graphic is an example, and currently circulating influenza clades and subclades may differ from those presented here.

Influenza Vaccine Viruses

Current seasonal flu vaccines are formulated to protect against influenza viruses known to cause epidemics, including: one influenza A(H1N1) virus, one influenza A(H3N2) virus, one influenza B/Victoria lineage virus, and one influenza B/Yamagata lineage virus. Getting a flu vaccine can protect against these viruses as well as additional flu viruses that are antigenically similar to the viruses used to make the vaccine. Information about this season’s vaccine can be found at Preventing Seasonal Flu with Vaccination. Seasonal flu vaccines do not protect against influenza C or D viruses or against zoonotic (animal-origin) flu viruses that can cause human infections, such as variant or avian (bird) flu viruses. In addition, flu vaccines will NOT protect against infection and illness caused by other viruses that also can cause influenza-like symptoms. There are many other viruses besides influenza that can result in influenza-like illness (ILI) that spread during flu season.

To learn more, please visit https://www.cdc.gov/flu/about/viruses/types.htm.

Who should get a flu vaccine this season?

Everyone 6 months and older should get a flu vaccine every season with rare exceptions. Vaccination is particularly important for people who are at higher risk of serious complications from influenza. A full listing of people at Higher Risk of Developing Flu-Related Complications is available.

Flu vaccination has important benefits. It can reduce flu illnesses, visits to doctor’s offices, and missed work and school due to flu, as well as make symptoms less severe and reduce flu-related hospitalizations and deaths.

Different flu vaccines are approved for use in different age groups.

• There are several flu shots approved for use in people as young as 6 months old and older, and two are approved only for adults 65 years and older.
• Flu shots also are recommended for pregnant people and people with certain chronic health conditions.
• The nasal spray flu vaccine is approved for use in people 2 years through 49 years of age. People who are pregnant and people with certain medical conditions should not receive the nasal spray flu vaccine.

There are many vaccine options to choose from.

• For people younger than 65 years, CDC does not recommend any one flu vaccine over another.
• For adults 65 years and older, there are three flu vaccines that are preferentially recommended for people 65 years and older. These are Fluzone High-Dose Quadrivalent vaccine, Flublok Quadrivalent recombinant flu vaccine and Fluad Quadrivalent adjuvanted flu vaccine. If none of the three flu vaccines preferentially recommended for people 65 and older is available at the time of administration, people in this age group can get any other age-appropriate flu vaccine instead.

The most important thing is for all people 6 months and older to get a flu vaccine every year.

If you have questions about which flu vaccine to get, talk to your doctor or other health care professional. More information is available at Who Should and Who Should NOT Get a Flu Vaccine.

Who Should Not Receive a Flu Shot:

Different influenza (flu) vaccines are approved for use in people in different age groups. In addition, some vaccines are not recommended for certain groups of people. Factors that can determine a person’s suitability for vaccination, or vaccination with a particular vaccine, include a person’s age, health (current and past) and any allergies to flu vaccine or its components. More information is available at Who Should and Who Should NOT get a Flu Vaccine.

Are any of the available flu vaccines recommended over others?

Yes, for some people. For the 2022-2023 flu season, there are three flu vaccines that are preferentially recommended for people 65 years and older. These are Fluzone High-Dose Quadrivalent vaccine, Flublok Quadrivalent recombinant  flu vaccine and Fluad Quadrivalent adjuvanted flu vaccine. This recommendation was based on a review of available studies which suggests that, in this age group, these vaccines are potentially more effective than standard dose unadjuvanted flu vaccines. There is no preferential recommendation for people younger than 65 years.

What if a preferentially recommended flu vaccine is not available?

If none of the three flu vaccines preferentially recommended for people 65 years and older is available at the time of administration, people in this age group should get any other age-appropriate flu vaccine instead.

Special Consideration Regarding Egg Allergy

People with egg allergies can receive any licensed, recommended age-appropriate influenza (flu) vaccine (IIV4, RIV4, ccIIV4, or LAIV4) that is otherwise appropriate. People who have a history of severe egg allergy (those who have had any symptom other than hives after exposure to egg) should be vaccinated in a medical setting, supervised by a health care provider who is able to recognize and manage severe allergic reactions. Two completely egg-free flu vaccine options are available: Flublok Quadrivalent recombinant flu vaccine and Flucelvax Quadrivalent cell-based flu shot.

Get vaccinated before flu season starts

It takes about two weeks after vaccination for antibodies that protect against flu to develop in the body.

When should I get vaccinated against flu?

For most people who need only one dose of flu vaccine for the season, September and October are generally good times to be vaccinated against flu. Ideally, everyone should be vaccinated by the end of October. Additional considerations concerning the timing of vaccination for certain groups of people include:

• Most adults, especially those 65 years and older, and pregnant people in the first or second trimester should generally not get vaccinated early (in July or August) because protection may decrease over time. However, early vaccination can be considered for any person who is unable to return at a later time to be vaccinated.
• Some children need two doses of flu vaccine. For those children it is recommended to get the first dose as soon as vaccine is available, because the second dose needs to be given at least four weeks after the first. Vaccination during July and August also can be considered for children who need only one dose.
• Vaccination during July and August also can be considered for people who are in the third trimester of pregnancy during those months, because this can help protect their infants for the first few months after birth (when they are too young to be vaccinated).

To learn more, please visit https://www.cdc.gov/flu/prevent/vaccinations.htm.

How do I know if I have the flu?

Your respiratory illness might be influenza (flu) if you have fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and/or fatigue. Some people may have vomiting and diarrhea, though this is more common in children. People may be sick with flu and have respiratory symptoms without a fever. Flu viruses usually cause the most illness during the colder months of the year. However, flu can also occur outside of the typical flu season. In addition, other viruses can also cause respiratory illness similar to flu. So, it is impossible to tell for sure if you have flu based on symptoms alone. If your doctor needs to know for sure whether you are sick with flu, there are laboratory tests that can be done.

What kinds of flu tests are there?

A number of tests are available to detect flu viruses in respiratory specimens. The most common are called “rapid influenza diagnostic tests (RIDTs).” RIDTs work by detecting the parts of the virus (antigens) that stimulate an immune response. These tests can provide results within approximately 10-15 minutes but may not be as accurate as other flu tests. Therefore, you could still have flu, even though your rapid test result is negative. Other flu tests called “rapid molecular assays” detect genetic material of the flu virus. Rapid molecular assays produce results in 15-20 minutes and are more accurate than RIDTs.

In addition to RIDTs and rapid molecular assays, there are several more accurate flu tests available that must be performed in specialized laboratories, such as hospital and public health laboratories. These tests include reverse transcription polymerase chain reaction (RT-PCR), viral culture, and immunofluorescence assays. All of these tests require that a health care provider swipe the inside of your nose or the back of your throat with a swab and then send the swab for testing. Results may take one to several hours.

How well can rapid tests detect flu?

During a flu outbreak, a positive rapid flu test is likely to indicate flu virus infection. However, rapid tests vary in their ability to detect flu viruses, depending on the type of rapid test used, and on the type of flu viruses circulating. Also, rapid tests appear to be better at detecting flu in children than in adults. This variation in ability to detect viruses can result in some people who are infected with flu having a negative rapid test result. This situation is called a false negative test result. Despite a negative rapid test result, your health care provider may diagnose you with flu based on your symptoms and their clinical judgment.

Will my health care provider test me for flu if I have flu-like symptoms?

While your doctor may test you for flu, not everyone who goes to the doctor with flu-like symptoms will be tested. After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement.

Please visit diagnosing flu for more information.

Difference Between Flu and COVID-19

Influenza (Flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a coronavirus named SARS-CoV-2, and flu is caused by infection with influenza viruses. You cannot tell the difference between flu and COVID-19 by symptoms alone because some of the symptoms are the same. Some PCR tests can differentiate between flu and COVID-19 at the same time. If one of these tests is not available, many testing locations provide flu and COVID-19 tests separately. Talk to a healthcare provider about getting tested for both flu and COVID-19 if you have symptoms.

Can I have flu and COVID-19 at the same time?

Yes. It is possible to have flu as well as other respiratory illnesses including COVID-19 at the same time. Health experts are still studying how common this can be.

Is there a test that can detect both flu and COVID-19?

Yes. There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. This test is being used by U.S. public health laboratories for surveillance purposes. Testing for these viruses at the same time will give public health officials important information about how flu and COVID-19 are spreading and what prevention steps should be taken. The test will also help public health laboratories save time and testing materials, and possibly to return test results faster.

The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorization for this new test. Initial test kits were sent to public health laboratories in early August 2020. CDC will continue to manufacture and distribute these kits.

More information for laboratories is available.

To learn more, please visit https://www.cdc.gov/flu/symptoms/testing.htm.

Influenza is primarily a community-based infection that is transmitted in households and community settings. Each year, 5% to 20% of U.S. residents acquire an influenza virus infection, and many will seek medical care in ambulatory healthcare settings (e.g., pediatricians’ offices, urgent-care clinics). In addition, more than 200,000 persons, on average, are hospitalized each year for influenza-related complications. Healthcare-associated influenza infections can occur in any healthcare setting and are most common when influenza is also circulating in the community. Therefore, the influenza prevention measures outlined in this guidance should be implemented in all healthcare settings. Supplemental measures may need to be implemented during influenza season if outbreaks of healthcare-associated influenza occur within certain facilities, such as long-term care facilities and hospitals [refs: Infection Control Measures for Preventing and Controlling Influenza Transmission in Long-Term Care Facilities].

Influenza Modes of Transmission

Traditionally, influenza viruses have been thought to spread from person to person primarily through large-particle respiratory droplet transmission (e.g., when an infected person coughs or sneezes near a susceptible person). Transmission via large-particle droplets requires close contact between source and recipient persons, because droplets generally travel only short distances (approximately 6 feet or less) through the air. Indirect contact transmission via hand transfer of influenza virus from virus-contaminated surfaces or objects to mucosal surfaces of the face (e.g., nose, mouth) may also occur. Airborne transmission via small particle aerosols in the vicinity of the infectious individual may also occur; however, the relative contribution of the different modes of influenza transmission is unclear. Airborne transmission over longer distances, such as from one patient room to another has not been documented and is thought not to occur. All respiratory secretions and bodily fluids, including diarrheal stools, of patients with influenza are considered to be potentially infectious; however, the risk may vary by strain. Detection of influenza virus in blood or stool in influenza infected patients is very uncommon.

Fundamental Elements to Prevent Influenza Transmission

Preventing transmission of influenza virus and other infectious agents within healthcare settings requires a multi-faceted approach. Spread of influenza virus can occur among patients, HCP, and visitors; in addition, HCP may acquire influenza from persons in their household or community. The core prevention strategies include:

• administration of influenza vaccine
• implementation of respiratory hygiene and cough etiquette
• appropriate management of ill HCP
• adherence to infection control precautions for all patient-care activities and aerosol-generating procedures
• implementing environmental and engineering infection control measures.

Successful implementation of many, if not all, of these strategies is dependent on the presence of clear administrative policies and organizational leadership that promote and facilitate adherence to these recommendations among the various people within the healthcare setting, including patients, visitors, and HCP. These administrative measures are included within each recommendation where appropriate. Furthermore, this guidance should be implemented in the context of a comprehensive infection prevention program to prevent transmission of all infectious agents among patients and HCP.

To learn more, please visit https://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm.

Steps to take if you get flu

1. If you get very sick, are pregnant, or are 65 years or older, or are otherwise at high risk of flu-related complications, call your doctor. You might need antiviral drugs to treat flu.
2. Stay at home and rest.
3. Avoid close contact with well people in your house so you won’t make them sick.
4. Drink plenty of water and other clear liquids to prevent fluid loss (dehydration).

When caring for people who have flu:

• Avoid being face-to-face with the sick person. If possible, it is best to spend the least amount of time in close contact with a sick person.
• When holding sick children, place their chin on your shoulder so they will not cough in your face.
• Wash your hands often and right way.
• If soap and water are not available, use an alcohol-based hand rub.
• Make sure to wash your hands after touching the sick person. Wash after handling their tissues or laundry.

Emergency Warning Signs of Flu Complications

People experiencing these warning signs should obtain medical care right away.

In Children:

• Fast breathing or trouble breathing
• Bluish lips or face
• Robs pulling in with each breath
• Chest pain
• Severe muscle pain (child refuses to walk)
• Dehydration (no urine for 8 hours, dry mouth, no tears when crying)
• Not alert or interacting when awake
• Seizures
• Fever above 104 degrees Fahrenheit that is not controlled by fever-reducing medicine
• In children younger than 12, any fever
• Fever or cough that improve but then return or worsen
• Worsening of chronic medical conditions

In Adults:

• Difficulty breathing or shortness of breath
• Persistent pain or pressure in the chest or abdomen
• Persistent dizziness, confusion, inability to arouse
• Seizures
• Not urinating
• Severe muscle pain
• Severe weakness or unsteadiness
• Fever or cough that improve but then return or worsen
• Worsening of chronic medical conditions

These lists are not all-inclusive. Please consult your medical provider for any other symptom that is severe or concerning.

To learn more, please visit https://www.cdc.gov/flu/treatment/caring-for-someone.htm.

Can flu be treated?

Yes. There are prescription medications called “antiviral drugs” that can be used to treat flu illness. CDC recommends prompt treatment for people who have flu or suspected flu and who are at higher risk of serious flu complications, such as people with asthma, diabetes (including gestational diabetes), or heart disease.

What are flu antiviral drugs?

Flu antiviral drugs are prescription medicines (pills, liquid, an inhaled powder, or an intravenous solution) that fight against flu viruses in your body. Antiviral drugs are not sold over the counter. You can only get them if you have a prescription from a health care provider. Antiviral drugs are different from antibiotics, which fight against bacterial infections. Antiviral drugs for flu only work to treat flu. Flu antiviral drugs are different than antiviral drugs used to treat other infectious diseases such as COVID-19. Antiviral drugs prescribed to treat COVID-19 are not approved or authorized to treat flu.

What should I do if I think I am sick with flu?

If you get sick with flu, antiviral drugs are a treatment option. Check with your doctor promptly if you are at higher risk of serious flu complications (full list of higher risk factors) and you develop flu symptoms. Flu signs and symptoms can include feeling feverish or having a fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. However, not everyone with the flu has a fever. Your doctor may prescribe antiviral drugs to treat your flu illness.

Should I still get a flu vaccine?

Yes. Antiviral drugs are not a substitute for getting a flu vaccine. While flu vaccine can vary in how well it works, a flu vaccine is best way to help prevent seasonal flu and its potentially serious complications. Everyone 6 months and older should receive a flu vaccine every year. Antiviral drugs are a second line of defense that can be used to treat flu (including seasonal flu and variant flu viruses) if you get sick.

What are the benefits of antiviral drugs?

When treatment is started within two days of becoming sick with flu symptoms, antiviral drugs can lessen fever and flu symptoms and shorten the time you are sick by about one day. They also may reduce the risk of complications such as ear infections in children, respiratory complications requiring antibiotics, and hospitalization in adults. For people at higher risk of serious flu complications, early treatment with an antiviral drug can mean having milder illness instead of more severe illness that might require a hospital stay. For adults hospitalized with flu illness, some studies have reported that early antiviral treatment can reduce their risk of death.

When should antiviral drugs be taken for treatment?

Antiviral treatment provides the greatest benefit when started soon after flu illness begins. Studies show that flu antiviral drugs work best for treatment when they are started within two days of getting sick. However, starting them later can still be beneficial, especially if the sick person is at higher risk of serious flu complications or is in the hospital with more severe illness.  Follow instructions for taking these drugs. Follow your doctor’s instructions and the dose, frequency, and duration listed on the label instructions for taking these drugs.

What antiviral drugs are recommended this flu season?

There are four FDA-approved antiviral drugs recommended by CDC to treat flu this season.

• oseltamivir phosphate (available as a generic version or under the trade name Tamiflu®),
• zanamivir (trade name Relenza®)
• peramivir (trade name Rapivab®), and
• baloxavir marboxil (trade name Xofluza®).

Generic oseltamivir and Tamiflu® are available as a pill or liquid suspension and are FDA approved for early treatment of flu in people 14 days and older.

Zanamivir is a powdered medication that is inhaled and approved for early treatment of flu in people 7 years and older. (Note: Zanamivir (trade name Relenza®) is administered using an inhaler device and is not recommended for people with breathing problems like asthma or COPD.) Oseltamivir and zanamivir are given twice a day for five days.

Peramivir is given once intravenously by a health care provider and is approved for early treatment of flu in people 6 months and older.

Baloxavir is a pill given as a single dose by mouth and is approved for early treatment of flu in children aged 5 years to less than 12 years who do not have any chronic medical conditions, and for all people aged 12 years and older. (Note: Baloxavir (trade name Xofluza®) is not recommended for treatment of flu in pregnant people, lactating  people, or in outpatients with complicated or progressive illness because there is no information about use of baloxavir in these patients. Baloxavir is also not recommended for treatment of flu in hospitalized patients due to limited data.)

How long should antiviral drugs be taken?

To treat flu, oseltamivir or inhaled zanamivir are usually prescribed for five days, while one dose of intravenous peramivir or one dose of oral Baloxavir are usually prescribed.  Oseltamivir treatment is given to hospitalized patients, and some patients might be treated for more than five days.

What are the possible side effects of antiviral drugs?

Side effects vary for each medication. The most common side effects for oseltamivir are nausea and vomiting. Zanamivir can cause bronchospasm, and peramivir can cause diarrhea. Other less common side effects also have been reported. Your health care provider can give you more information about these drugs or you can check the Food and Drug Administration (FDA) website for specific information about antiviral drugs, including the manufacturer’s package insert.

Can pregnant people take antiviral drugs?

Yes. Oral oseltamivir is recommended for treatment of pregnant people with flu because compared to other recommended antiviral medications, it has the most studies available to suggest that it is safe and beneficial during pregnancy. Baloxavir is not recommended for pregnant people or while breastfeeding, as there are no available efficacy or safety data.

Who should take antiviral drugs?

It’s very important that flu antiviral drugs are started as soon as possible to treat patients who are hospitalized with flu, people who are very sick with flu but who do not need to be hospitalized, and people who are at higher risk of serious flu complications based on their age or health, if they develop flu symptoms. Although other people with mild illness who are not at higher risk of flu complications may also be treated early with antiviral drugs by their doctor, most people who are otherwise healthy and not at higher risk for flu complications do not need to be treated with antiviral drugs.

Following is a list of all the health and age factors that are known to increase a person’s risk of getting serious complications from the flu:

• Asthma
• Neurologic and neurodevelopment conditions
• Blood disorders (such as sickle cell disease)
• Chronic lung disease (such a chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
• Endocrine disorders (such as diabetes mellitus)
• Heart disease (such a congenital heart disease, congestive heart failure and coronary artery disease)
• Kidney disorders
• Liver disorders
• Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
• People who are obese with a body mass index [BMI] of 40 or higher
• People younger than 19 years of age on long-term aspirin- or salicylate-containing medications.
• People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)

Other people at higher risk from flu:

• Adults 65 years and older
• Children younger than 2 years old
• Pregnant women and women up to 2 weeks after the end of pregnancy
• People from certain racial and ethnic minority groups, including non-Hispanic Black, Hispanic or Latino, and American Indiana or Alaska Native persons
• People who live in nursing homes and other long-term care facilities.
• Although all children younger than 5 years old are considered at higher risk for serious flu complications, the highest risk is for those younger than 2 years old, with the highest hospitalization and death rates among infants younger than 6 months old.

To learn more, please visit https://www.cdc.gov/flu/treatment/whatyoushould.htm.

PERSON TO PERSON

People with flu can spread it to others. Most experts think that flu viruses spread mainly by droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby (usually within about 6 feet away) or possibly be inhaled into the lungs. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose, or possibly their eyes.

WHEN ARE PEOPLE WITH FLU CONTAGIOUS?

Flu viruses can be detected in most infected persons beginning one day before symptoms develop and up to five to seven days after becoming sick. People with flu are most contagious in the first three to four days after their illness begins. However, infants and people with weakened immune systems who are infected with flu viruses may be contagious for longer than seven days.

Symptoms typically begin about two days (but can range from one to four days) after flu viruses infect a person’s respiratory tract. It is theoretically possible that before symptoms begin, an infected person can spread flu viruses to their close contacts. Some people can be infected with flu viruses and have no symptoms but may still be able to spread the virus to their close contacts.

To learn more, please visit https://www.cdc.gov/flu/about/disease/spread.htm.

Getting an annual flu vaccine is the best way to protect yourself and your loved ones from flu.

If you are at higher risk of developing serious flu complications, flu vaccination is especially important. When you get vaccinated, you reduce your risk of getting sick with flu and possibly being hospitalized or dying from flu.

Following is a list of all the health and age factors that are known to increase a person’s risk of getting serious flu complications:

• Adults 65 years and older
• Children younger than 2 years old¹
• Asthma
• Neurologic and neurodevelopment conditions
• Blood disorders (such as sickle cell disease)
• Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
• Endocrine disorders (such as diabetes mellitus)
• Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)
• Kidney diseases
• Liver disorders
• Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
• People who are obese with a body mass index [BMI] of 40 or higher
• People younger than 19 years old on long-term aspirin- or salicylate-containing medications.
• People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)
• People who have had a stroke

Other people at higher risk from flu:

• Pregnant people and people up to 2 weeks after the end of pregnancy
• People who live in nursing homes and other long-term care facilities
• People from certain racial and ethnic minority groups are at increased risk for hospitalization with flu, including non-Hispanic Black persons, Hispanic or Latino persons, and American Indian or Alaska Native persons
• ¹ Although all children younger than 5 years old are considered at higher risk of serious flu complications, the highest risk is for those younger than 2 years old, with the highest hospitalization and death rates among infants younger than 6 months old.

Information on groups at higher risk from COVID-19 is available.

To learn more information, please visit https://www.cdc.gov/flu/highrisk/index.htm.

Misconceptions about Flu Vaccines

Can a flu vaccine give you flu?

No, flu vaccines cannot cause flu illness. Flu vaccines given with a needle (i.e., flu shots) are made with either inactivated (killed) viruses, or with only a single protein from the flu virus.  The nasal spray vaccine contains live viruses that are attenuated (weakened) so that they will not cause illness.

Are any of the available flu vaccines recommended over the others?

Yes, for some people. For the 2022-2023 flu season, there are three flu vaccines that are preferentially recommended for people 65 years and older. These are Fluzone High-Dose Quadrivalent vaccine, Flublok Quadrivalent recombinant  flu vaccine and Fluad Quadrivalent adjuvanted flu vaccine. This recommendation was based on a review of available studies which suggests that, in this age group, these vaccines are potentially more effective than standard dose unadjuvanted flu vaccines. There is no preferential recommendation for people younger than 65 years.

What if a preferentially recommended flu vaccine is not available?

If none of the three flu vaccines preferentially recommended for people 65 years and older is available at the time of administration, people in this age group should get any other age-appropriate flu vaccine instead.

Is it better to get sick with flu than to get a flu vaccine?

No. Flu can be a serious disease, particularly among young children, older adults, and people with certain chronic health conditions, such as asthma, heart disease or diabetes. Any flu infection can carry a risk of serious complications, hospitalization or death, even among otherwise healthy children and adults. Therefore, getting vaccinated is a safer choice than risking illness to obtain immune protection.

Do I really need a flu vaccine every year?

Yes. CDC recommends a yearly flu vaccine for everyone 6 months of age and older with rare exception. The reason for this is that a person’s immune protection from vaccination declines over time, so an annual vaccination is needed to get the “optimal” or best protection against the flu. Additionally, flu viruses are constantly changing, so the vaccine composition is reviewed each year and updated as needed.

Why do some people not feel well after getting a seasonal flu vaccine?

Some people report having mild side effects after flu vaccination. The most common side effects from flu shots are soreness, redness, tenderness or swelling where the shot was given. Low-grade fever, headache and muscle aches also may occur. If these reactions occur, they usually begin soon after vaccination and last 1-2 days.

Side effects from the nasal spray flu vaccine may include: runny nose, wheezing, headache, vomiting, muscle aches, fever, sore throat and cough. If these problems occur, they usually begin soon after vaccination and are mild and short-lived. The most common reactions people have to flu vaccines are considerably less severe than the symptoms caused by actual flu illness.

• Carolyn Bridges et al. (2000). Effectiveness and cost-benefit of influenza vaccination of healthy working adults: A randomized controlled trial.

What about serious reactions to flu vaccine?

Serious allergic reactions to flu vaccines are very rare. If they do occur, it is usually within a few minutes to a few hours after vaccination. While these reactions can be life-threatening, effective treatments are available.

What about people who get a seasonal flu vaccine and still get sick with flu symptoms?

There are several reasons why someone might get flu symptoms even after they have been vaccinated against flu.

• Someone can get sick with another respiratory virus besides flu such as rhinoviruses or SARS-CoV-2 (the virus that causes COVID-19). Other respiratory viruses can cause symptoms similar to flu, and they can also spread and cause illness during flu season. Flu vaccines only protect against flu and its complications, not other illnesses.
• Someone can be exposed to flu viruses shortly before getting vaccinated or during the two-week period after vaccination that it takes the body to develop immune protection. This exposure may result in a person becoming sick with flu before protection from vaccination takes effect.
• Flu vaccines vary in how well they work, and someone can get vaccinated but still get sick with flu. There are many different flu viruses that spread and cause illness among people, so this can happen if someone is exposed to a flu virus that is very different from the viruses in the flu vaccine. The ability of a flu vaccine to protect a person depends partially on the similarity or “match” between the vaccine viruses chosen to make vaccine and those spreading and causing illness. Even when that happens though, flu vaccination can still reduce severity of illness.

Can vaccinating someone twice provide added immunity?

In adults, studies have not shown a benefit from getting more than one dose of vaccine during the same influenza season, even among elderly persons with weakened immune systems. Except for children getting vaccinated for the first time, only one dose of flu vaccine is recommended each season.

Is it true that getting a flu vaccine can make you more susceptible to other respiratory viruses?

Flu vaccines are not thought to make people more susceptible to other respiratory infections.

A 2012 study that suggested that flu vaccination might make people more susceptible to other respiratory infections. After that study was published, many experts looked into this issue further and conducted additional studies to see if the findings could be replicated. No other studies have found this effect. It’s not clear why this finding was detected in the one study, but the majority of evidence suggests that this is not a common or regular occurrence and that flu vaccination does not, in fact, make people more susceptible to other respiratory infections.

• Maria Sundaram et al. (2013). Influenza Vaccination Is Not Associated With Detection of Noninfluenza Respiratory Viruses in Seasonal Studies of Influenza Vaccine Effectiveness.

Does a flu vaccination increase your risk of getting COVID-19?

There is no evidence that getting a flu vaccination increases your risk of getting sick from a coronavirus, like the one that causes COVID-19.

You may have heard about a study published in January 2020 that reported an association between flu vaccination and risk of four commonly circulating seasonal coronaviruses, but not the one that causes COVID-19. This report was later found to be incorrect.

The results from that initial study led researchers in Canada to look at their data to see if they could find similar results in their population. The results from this study showed that flu vaccination did not increase risk for these seasonal coronaviruses. The Canadian findings highlighted the protective benefits of flu vaccination.

The Canadian researchers also identified a flaw in the methods of the first study, noting that it violated the part of study design that compares vaccination rates among patients with and without flu (test negative design). This flaw led to the incorrect association between flu vaccination and seasonal coronavirus risk. When these researchers reexamined data from the first study using correct methods, they found that flu vaccination did not increase risk for infection with other respiratory viruses, including seasonal coronaviruses.

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Misconceptions about Flu Vaccine Effectiveness

Influenza (flu) vaccine effectiveness (VE) can vary. The protection provided by a flu vaccine varies from season to season and depends in part on the age and health status of the person getting the vaccine and the similarity or “match” between the viruses in the vaccine and those in circulation. During years when the flu vaccine match is good, it is possible to measure substantial benefits from flu vaccination in terms of preventing flu illness and complications. However, the benefits of flu vaccination will still vary, depending on characteristics of the person being vaccinated (for example, their health and age), what flu viruses are circulating that season and, potentially, which type of flu vaccine was used. More information is available at Vaccine Effectiveness – How well does the Flu Vaccine Work.

Below is a summary of the benefits of flu vaccination and selected scientific studies that support these benefits.

• Flu vaccination can keep you from getting sick with flu.
  • Flu vaccine prevents millions of illnesses and flu-related doctor’s visits each year. For example, during 2019-2020, the last flu season prior to the COVID-19 pandemic, flu vaccination prevented an estimated 7.5 million influenza illnesses, 3.7 million influenza-associated medical visits, 105,000 influenza-associated hospitalizations, and 6,300 influenza-associated deaths.
  • During seasons when flu vaccine viruses are similar to circulating flu viruses, flu vaccine has been shown to reduce the risk of having to go to the doctor with flu by 40% to 60%.
• Flu vaccination has been shown in several studies to reduce severity of illness in people who get vaccinated but still get sick.
  • A 2021 study showed that among adults hospitalized with flu, vaccinated patients had a 26% lower risk of intensive care unit (ICU) admission and a 31% lower risk of death from flu compared with those who were unvaccinated.
  • A 2018 study showed that among adults hospitalized with flu, vaccinated patients were 59% less likely to be admitted to the ICU than those who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent four fewer days in the hospital than those who were not vaccinated.
• Flu vaccination can reduce the risk of flu-associated hospitalization.
  • Flu vaccine prevents tens of thousands of hospitalizations each year. For example, during 2019-2020 flu vaccination prevented an estimated 105,000 flu-related hospitalizations.
  • A 2018 study showed that from 2012 to 2015, flu vaccination among adults reduced the risk of being admitted to an ICU with flu by 82%.
  • A 2017 study found that during 2009-2016, flu vaccines reduced the risk of flu-associated hospitalization among older adults by about 40% on average.
  • A 2014 study showed that flu vaccination reduced children’s risk of flu-related pediatric intensive care unit (PICU) admission by 74% during flu seasons from 2010-2012.
• Flu vaccination is an important preventive tool for people with certain chronic health conditions.
  • Flu vaccination has been associated with lower rates of some cardiac events among people with heart disease, especially among those who have had a cardiac event in the past year.
  • Flu vaccination can reduce the risk of a flu-related worsening of chronic lung disease (for example, chronic obstructive pulmonary disease (COPD) requiring hospitalization).
  • Among people with diabetes and chronic lung disease,flu vaccination has been shown in separate studies to be associated with reduced hospitalizations from a worsening of their chronic condition.
• Flu vaccination during pregnancy helps protect pregnant people from flu during and after pregnancy and helps protect their infants from flu in their first few months of life.
  • A 2013 study showed that during the 2010–2011 and 2011–2012 flu seasons vaccination reduced the risk of flu-associated acute respiratory infection in pregnant people by about one-half.
  • A 2018 study showed that getting a flu shot reduced a pregnant person’s risk of being hospitalized with flu by an average of 40% from 2010-2016.
  • A number of studies have shown that in addition to helping to protect pregnant people from flu, a flu vaccine given during pregnancy helps protect the baby from flu for several months after birth, when babies are too young to be vaccinated.
• Flu vaccine can be lifesaving in children.
  • A 2022 study showed that flu vaccination reduced children’s risk of severe life-threatening influenza by 75%.
  • A 2020 study found that during the 2018-2019 flu season, flu vaccination reduced flu-related hospitalization by 41% and flu-related emergency department visits by half among children (aged 6 months to 17 years old).
  • A 2017 study was the first of its kind to show that flu vaccination can significantly reduce children’s risk of dying from flu.
• Getting vaccinated yourself may also protect people around you, including those who are more vulnerable to serious flu illness, like babies and young children, older people, and people with certain chronic health conditions.

Despite the many benefits offered by flu vaccination, only about half of Americans get an annual flu vaccine. During an average flu season, flu can cause millions of illnesses, hundreds of thousands of hospitalizations and tens of thousands of deaths. Many more people could be protected from flu if more people got vaccinated.

*References for the studies listed above can be found at Publications on Influenza Vaccine Benefits.

Misconceptions about the Timing of Seasonal Influenza Vaccination

Should I wait to get vaccinated so that my immunity lasts through the end of the season?

How long you are immune or your “duration of immunity” is discussed in the ACIP recommendations. While delaying getting of vaccine until later in the fall may lead to higher levels of immunity during winter months, this should be balanced against possible risks, such as missed opportunities to receive vaccine and difficulties associated with vaccinating a large number of people within a shorter time period.

Is it too late to get vaccinated after Thanksgiving (or the end of November)?

No. Vaccination can still be beneficial as long as flu viruses are circulating. If you have not been vaccinated by Thanksgiving (or the end of November), it can still be protective to get vaccinated in December or later. Flu is unpredictable and seasons can vary. Seasonal flu disease usually peaks between December and March most years, but disease can occur as late as May.

Misconceptions about Physician Consent for Vaccination

Do pregnant people or people with pre-existing medical conditions need special permission or written consent from their doctor to get a flu vaccine?

No. There is no recommendation for pregnant people or people with pre-existing medical conditions to seek special permission or secure written consent from their doctor for vaccination if they get vaccinated at a worksite clinic, pharmacy or other location outside of their physician’s office. With rare exception, CDC recommends an annual flu vaccine for everyone 6 months of age and older, including pregnant people and people with medical conditions.

A variety of flu vaccines are available (Table 1). Vaccine providers should be aware of the approved age indications of the vaccine they are using and of any contraindications or precautions. Providers also should appropriately screen all people getting vaccinated for allergies to vaccine components or other contraindications. People who have previously had a severe allergic reaction to influenza vaccine or any of its ingredients should generally not be vaccinated.

There are some people who should not get a flu vaccine without first speaking with their doctor. These include:

• People who have a moderate-to-severe illness with or without a fever (they should wait until they recover to get vaccinated), and
• People with a history of Guillain-Barré Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine. Tell your doctor if you ever had Guillain-Barré Syndrome. Your doctor will help you decide whether the vaccine is recommended for you.

Pregnant people or people with pre-existing medical conditions who get vaccinated should get a flu shot.

If a person is vaccinated by someone other than their primary health care provider, the vaccinating provider should ensure that the patient and, if possible, the patient’s medical provider have documentation of vaccination.

For a complete list of people who should not get a flu vaccine before speaking with their doctor, please review the influenza Vaccine Information Statement for the inactivated or recombinant flu vaccine or live, intranasal influenza vaccine.

Misconceptions about “Stomach Flu”

Is the “stomach flu” really flu?

No. Many people use the term “stomach flu” to describe illnesses with nausea, vomiting or diarrhea. These symptoms can be caused by many different viruses, bacteria or even parasites. While vomiting, diarrhea, and being nauseous or “sick to your stomach” can sometimes be related to flu — more commonly in children than adults — these problems are rarely the main symptoms of influenza. Flu is a respiratory disease and not a stomach or intestinal disease.

To learn more, please visit https://www.cdc.gov/flu/prevent/misconceptions.htm.