Do Flu Shots Protect All Season Long?

H3N2 flu vaccine protection decreases 33% within 6 months

Whether influenza vaccination offers protection for the duration of the influenza season has been a debated question for many years.

A new meta-analysis of 14 studies shows that the vaccine effectiveness (VE) against influenza can vary by type and subtype.

This research found Influenza A H3N2 VE decreases by 33% within the first 6 months of immunization.

But, the VE against influenza B declined by only 19%, and influenza A H1N1’s decrease was not statistically relevant.

These researchers said exploring influenza vaccination timing must be a priority for disease control.

Specifically, vaccination timing in tropical countries with year-round influenza virus activity should be a priority.

This means, when it comes to flu shot efficacy, multiple vaccinations throughout the year might maximize VE.

The Centers for Disease Control and Prevention (CDC) recommends it’s best to get vaccinated before flu begins spreading in your community.

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

"Haven't received your flu shot yet?  That's okay, it's not too late.  According to the CDC, peak flu season occurs between December and February," said Alexandria Duffield, Pharm.D., Brookshire Grocery Company.

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"Come to any BGC Pharmacy today so we can help protect both you and your family this flu season.  Your health is our number one priority", said Duffield.

Getting vaccinated later can still be beneficial and vaccination continues to be offered throughout the flu season, even into January or later.

Most pharmacies in the USA offer several FDA approved flu vaccines.

The flu shot cost varies depending on your insurance and which state you live.

The CDC Vaccine Price List provides the private sector vaccine prices for general information.

Flu vaccine discounts can be found here.

These researchers reviewed VE data collected in Europe, the United States, Kenya, Thailand, and Australia, from 2009 to 2016.

These researchers did not disclose any conflicts of interest: Barnaby Young, Sapna Sadarangani, Lili Jiang, Annelies Wilder-Smith, Mark I-Cheng Chen.

Any correspondence should be addressed to Dr. Barnaby Young at the Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng Hospital, Singapore 308433. email: [email protected]

The Duration of Influenza Vaccine Effectiveness: A Systematic Review, Meta-analysis and Meta-regression of Test-Negative Design Case-control Studies, The Journal of Infectious Diseases.