Flu FAQ

Flu Vaccines

Getting your flu shot is the first and most important step in protecting against flu viruses. Every year, flu vaccination prevents illnesses, medical visits, hospitalizations, and deaths.

Anyone age 6 months and up should receive an annual flu vaccine.

Find your flu shot via our Immunization Clinics page. CDPH is hosting clinics throughout the city, but you can also find flu shots at your local pharmacy or at your healthcare provider.

CDC recommends that everyone age 6 months or older with egg allergy of any severity can and should get an annual flu vaccine. Any flu vaccine (egg-based or non-egg based) appropriate for the person's age and health status can be used. All vaccines should be administered in settings where people and materials necessary to respond to acute allergic reactions are available.

https://www.immunize.org/catg.d/p3125.pdf

Most flu vaccines are made using an egg-based manufacturing process and contain a small amount of egg protein called ovalbumin.

https://www.cdc.gov/flu/vaccine-process/

Severe allergic reactions (such as anaphylaxis) to vaccines are extremely rare. They occur in one to two out of every million doses given. It typically happens within minutes to hours after vaccination. Although severe allergic reactions to vaccines are rare, they

sometimes happen in people who do not have any known allergies. For this reason, it is recommended that all vaccines be given in a setting where allergic reactions can be recognized and managed quickly.

https://www.cdc.gov/flu/prevent/egg-allergies.htm


COVID-19 Vaccines and Your Flu Shot

We don’t know what this flu season will be like but we do know that having flu and COVID-19 at the same time can be even worse than having one or the other by itself. We know that Australia, which has opposite seasons to the Northern Hemisphere, is having a bad flu season right now, which suggests we may have a bad flu season this fall and winter. This is not the year to skip your flu vaccine. Children under 5 years old, pregnant people, and adults over 65 years old are at high risk of getting sicker from flu.

Being up-to-date on your COVID-19 vaccines protects against serious outcomes from the virus - especially for seniors and people with underlying medical conditions who are at higher risk for severe complications.

Both the flu and COVID-19 vaccines are recommended for everyone over the age of 6 months.

No. You should look out for arm soreness and redness as well as flu-like symptoms (including fever, cough, nausea, vomiting, muscle aches, headache) for 48-72 hours after being vaccinated. Contact your primary care provider if you have any concern about the symptoms or have symptoms for more than 72 hours. 

Yes. COVID-19 vaccines are safe to co-administer with many other vaccines on the same day, including the flu vaccine. They can either be given one in each arm or spaced out on the same arm. Both flu and COVID-19 vaccines are available at no cost. 

Both vaccines are widely available citywide and offered at many doctor’s offices and pharmacies. Visit our vaccine clinics page to see a list of CDPH-hosted vaccination clinics.


Flu Myths

No. The injected flu vaccine contains an inactivated (killed) virus and can’t make you sick. The nasal spray vaccine contains live viruses that are attenuated (weakened) so that they will not cause illness. If you feel achy or slightly feverish, it is a normal reaction of the immune system to the vaccine, and generally lasts only a day or two.

Those who believe they came down with the flu after getting vaccinated were most likely suffering from an unrelated upper-respiratory sickness or already were infected with flu when they received the shot. It takes about two weeks for the vaccine to start preventing flu.

No. Many people believe they have the flu but in fact are suffering from a different respiratory virus. It's also possible that you were exposed to influenza before the vaccine kicked in, or you came down with a strain of flu that wasn't included in that year's shot.

Still, vaccinated people who do get sick with flu normally experience milder symptoms than those who skip the shot. It could save you from having to see a doctor, take a week off work or, even worse, be hospitalized.

Yes. Many people use the term "flu" to refer to a cold or other respiratory illness. However, influenza is a serious disease that can lead to hospitalization and death.

During the 2017-18 flu season, 80,000 people in the U.S. died of influenza and 900,000 people were hospitalized, according to preliminary estimates by the CDC.

Not for most people. The flu shot has one of the best safety records of any vaccine, and the majority of side effects are mild. The most common complaint after flu vaccination is soreness and tenderness at the injection site.

Severe side effects are extremely rare. One in a million people may get Guillain-Barré Syndrome (GBS), which cause muscle weakness and paralysis.

Yes. The CDC recommends that everyone 6 months and older get vaccinated for the flu. That's because influenza is a contagious disease and can lead to serious illness, including pneumonia, as well as missed work or even hospitalization for otherwise healthy people.

The CDC estimates that flu vaccination prevented an estimated 4.4 million influenza illnesses, 2.3 million influenza-associated medical visits, 58,000 influenza-associated hospitalizations, and 3,500 influenza-associated deaths during 2018-2019.

Healthy people also can spread the virus to others who are particularly susceptible, including newborn babies, senior citizens, and those with weakened immune systems.

Yes. Pregnant women should especially get the flu vaccine since some of the changes to the heart, lung, and immune system that occur during pregnancy make them more susceptible to severe illness from flu, including illness that requires hospitalization. The inactivated flu vaccine is safe at any stage of pregnancy.  

Getting the flu shot while​ pregnant even protects your baby from the flu for months after delivery. That's particularly important because infants younger than 6 months can't get flu shots of their own and are more likely to suffer serious complications from the flu. 

Yes. To protect yourself and others from the flu, you must get the vaccine every year. That's because the vaccine formulation changes each year to protect against specific viruses circulating that season.