

Q&A on flu - answers from infectious disease specialist Dr. Sarah Haessler

October 08, 2015

By Dr. Sarah Haessler

Infectious Disease Division

Baystate Medical Center

Q. I’ve never been a big fan of the flu shot ever since I was vaccinated many years ago, then got sick shortly afterwards. Why is that? 

 A. I’m not sure exactly what you mean by being “sick” afterwards. So, I will address several possibilities.

If you are referring to having a low grade fever and general aches after being vaccinated, those are common side effects experienced by some, but they are mild and don’t last for very long, usually 1-2 days. Also, I’m not sure what “many years ago” translates into time wise, but side effects can differ for those opting for the newer nasal spray vaccine, which can cause a runny nose, headache, sore throat or cough.

While the flu vaccine is safe and rarely causes any serious problems, some people can have severe allergic reactions to the shot, especially those who are allergic to eggs. If that is your case, there are now flu vaccines that do not contain egg proteins, such as Flublok. There are also other flu vaccines approved by the Food and Drug Administration (FDA) that do not contain egg proteins, and are approved for those 18 years of age and older.

In extremely rare cases, some people have developed Guillain-Barre Syndrome after getting the flu vaccine, a disorder in which the body’s immune system attacks part of the nervous system. Again, whatever your case may be, you should check with your doctor about which vaccine is best for you.

 If you are referring to having a severe cold or flu-like illness after getting the shot, I can assure you it was purely coincidental. The flu vaccine does not contain any live flu virus, so you cannot get the flu from a flu shot. If you did indeed have influenza after getting the shot, you may have already been infected, or were infected shortly after receiving your vaccination. It takes around two weeks after vaccination for your body to make antibodies against the influenza virus.

Q. I hate to admit it, but needles scare me and that’s another reason why I never get the shot. Are there alternatives to shots?

 A. You’re not alone, and it’s nothing to be ashamed of. Many people are afraid of needles.

But, there are alternatives today that may not have been available to you when you received your last flu shot. There is a nasal spray vaccine called FluMist. However, it cannot be used by children younger than 2 years of age and adults over age 49, as well as anyone with asthma, pregnant women, and those with compromised immune systems.


Q. Even if I do decide to get the flu shot, I had a heart attack two years ago and my sister told me that if you have a serious illness, then you shouldn’t be vaccinated.

A. I’m not sure what illnesses your sister may have, but please tell her that she is misinformed.


Also, depending on your age, people 65 years and older are eligible for a new high dose vaccine containing four times the amount of antigen as a regular flu shot, and is associated with a stronger immune response and may translate into greater protection against the flu.

In general, everyone six months of age and older should be vaccinated unless their doctor recommends against it because of certain pre-existing conditions.

Q. It was widely reported in the media that last year’s vaccine was only marginally effective. Why is that?

A. You are correct. Last year the flu vaccine was only 19% effective in reducing your risk of getting the flu, the lowest since 2004 when it was only 10% effective. More years than not it has averaged between 47-60% effective.

What happens is that each year, based on data identifying the most common strains circulating around the world throughout the year, experts decide on what three strains of the virus to include in the current year’s vaccine. However, a mutation in one of the flu strains after the virus had already been manufactured last year resulted in the poor match.

While effectiveness varies from year to year, it’s still a good idea to get vaccinated to not only protect yourself, but others around you who are more vulnerable to serious flu illness. If you do get the flu, having the flu shot may make your illness milder.

Also, remember that adults and children are still hospitalized and others die each year from flu.


Q. If I decide to get the flu vaccine, am I too late?

A. No. It’s not too late.

Flu season usually runs from October to May and normally peaks in January or February. But, there have already been some documented cases of flu in the area. So, getting your shot early is the best strategy, since as I mentioned earlier, it takes around two weeks after vaccination for your body to make antibodies against the flu virus.

Q. How long will the flu shot last? Will I need another next year?

