How Does the Flu Vaccine Work?

As part of our week-long Flu Prevention series, we discuss what the flu vaccine is and how it works. There are very few people for whom a flu vaccine is not an option, so get one before you get sick!

Flu Vaccinations

The flu vaccine works by causing your body to develop antibodies that protect you against the influenza virus. Most flu vaccines protect against the three most common strains of the flu, which is why it is called a trivalent vaccine.

This year, a new quadrivalent vaccine has been introduced that protects against four types of flu viruses. The quadrivalent vaccine will likely be in shorter supply, however, and cost more money. There is also a nasal spray flu vaccine approved for the 2013-2014 flu season. This vaccine has only been approved for those aged 2-49 who are not pregnant.

The Center for Disease Control (CDC) does not recommend any one vaccine over the other, they only stress that you should get a vaccine. If quadrivalent vaccines are not available in your area, you should still get a trivalent flu vaccination.

The vaccination antibodies do not develop for about two weeks, so it is best to get vaccinated well before flu season, preferably by October. Flu season typically peaks around January.

Who Should Not Get a Flu Vaccine?

The flu vaccine is not approved for children less than 6 months of age. It is not recommended for:

People who are currently sick.
Those who have gotten any other vaccines within the last 4 weeks.
People with a history of Guillain-Barre Syndrome.
Those who have had adverse reactions to flu vaccines in the past.

Egg Allergies

People with severe allergic reactions to eggs may be advised not to get the flu vaccine. The vaccine has an egg base that can cause complications in those with egg allergies. This chart from the CDC shows their recommendations regarding egg allergies and the flu, but if you are unsure you should consult with your physician.

There is a new vaccine on the market this year that does not use eggs called Flublok. It is FDA approved only for those between the ages of 18 to 49.

Can the flu vaccine infect me?

The flu vaccine cannot cause you to get the flu because the virus is inactive in the vaccine. In the nasal spray vaccine, the virus is only slightly active and only lives in the cooler temperatures in your nose. Once it reaches the warmer parts of your body it is unable to survive. Since influenza is an infection of the upper respiratory system, it would die before it reaches this part of your body.

The bottom line is, it is a good idea for almost everyone to get a flu vaccine. The less people are infected with the flu, the less it will spread. If have any concerns, be sure to ask your doctor first. If you need any easy way to remember or share these tips, check out our Flu Vaccine Infographic.