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Flu shots build your immunity

By Dr. Caitlyn Nguyen, family medicine physician

I think of the flu vaccine as protection for our 80- and 90-year-old self. Our natural immune weakens with age, and it becomes much harder to fight off the flu. The elderly population is more prone to complications from the flu, including death.

It's never too late to start getting your vaccine. If you were to start getting the flu vaccine at age 50, by the time you're 80, you would have antibodies against 120 flu strains. It is the immunity we've accumulated in our lifetime that protects us in our 80s and 90s.

Argument: I don't get the flu

If you don't get the flu, that's great, but you also have not built any immunity to the flu. If you do not the flu vaccine, you have no protection against the flu. Because the flu is a virus, it mutates very quickly and that's why we need flu vaccines yearly.

We're playing catch-up with the flu, and we may never be able to catch up or eradicate the flu in our lifetime. Flu vaccine is the only true protection we have from the flu.

Argument: I get sick after getting the flu shot

The flu virus can lay dormant in your system for 7 days before manifesting symptoms. It's more likely a coincidence that you came down with the flu after getting the flu shot.

Flu shots contains inactivated flu virus — it cannot cause the flu. You may feel symptoms in terms of possible low-grade fever or discomfort, but it is your immune system reacting to the flu vaccine. It is your immune system's ways of telling you it is working.

Argument: Vaccine is not 100% effective

True. It is not 100% effective.

In a good year, we get about 70 to 80% protection from the prominent flu strains. In a bad year, we may have 20% protection. That's still 20% chance of not being sick with the flu, and you're continuing to build immunity against the flu. Even if you do get sick from the flu after getting the vaccine, you are now immune to 5 different strains instead of 4.

Down the road, if your immune system encounters a strain that is similar to a strain that your body has already been exposed to, you may not get as sick and would be able to fight off this strain much easier.

It takes 2 weeks for your body to build up the immunity after getting your flu vaccine. Peak season for flu begins in October. The CDC recommends getting your vaccine by the end of October for maximum effectiveness through the flu season.

Herd immunity

Protect yourself as well as the people around you, especially if you are around elderly relatives, infants or pregnant women. These three populations are at risk for death from the flu. If you don't catch the flu, you do not spread the flu.


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