When Should I Get My Flu Shot?

For most the folks, the real question isn’t if they should get a flu shot, but when.

When Should I Get My Flu Shot?

The original flu shot recommendations  were based on the fact that flu vaccine became available for distribution in September, but was not completed until December or January. And that high-risk folks should get vaccinated “to avoid missed opportunities for vaccination” if flu vaccine was available in September and they were already at a doctor’s appointment or in the hospital.

But for most people, the original recommendation was really that “the optimal time for vaccination efforts is usually during October–November.”

“Persons and institutions planning substantial organized vaccination campaigns (e.g., health departments, occupational health clinics, and community vaccinators) should consider scheduling these events after at least mid-October because the availability of vaccine in any location cannot be ensured consistently in early fall. Scheduling campaigns after mid- October will minimize the need for cancellations because vaccine is unavailable.”

Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2006)

What was the problem with this strategy?

Early flu seasons.

And trying to vaccinate over 100 million people in such a short time.

While it might work fine if flu season doesn’t hit until January or February, waiting until mid-October could leave a lot of folks unvaccinated if you had an early flu season that was peaking in November or December.

Fortunately, we don’t have to rush to get people vaccinated so quickly anymore. For one thing, manufacturers have gotten much better at distributing flu vaccine and are able to get a lot of the doses out at the very beginning of flu season. And with more manufacturers, we are seeing fewer delays and shortages of flu vaccine than we used to.

That’s why the recommendation on the timing of flu vaccination has changed over the years.

“In general, health-care providers should begin offering vaccination soon after vaccine becomes available and if possible by October. To avoid missed opportunities for vaccination, providers should offer vaccination during routine health-care visits or during hospitalizations whenever vaccine is available.”

Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2010)

That nice, simple message has changed yet again though.

To balance the concerns that getting a flu shot too early might leave you unprotected at the end of a late flu season, but getting a flu shot too late might leave you unprotected at the beginning of an early flu season, the recommendations from the CDC on the timing of flu vaccination changed again for the 2019-2020 season. While still encouraging vaccination by the end of October, they suggested that “for those requiring only 1 dose for the season, early vaccination (i.e., in July and August) is likely to be associated with suboptimal immunity before the end of the influenza season, particularly among older adults.”

• Balancing considerations regarding the unpredictability of timing of onset of the influenza season and concerns that vaccine-induced immunity might wane over the course of a season, vaccination is recommended to be offered by the end of October.
• Children aged 6 months through 8 years who require 2 doses (see Children Aged 6 Months Through 8 Years) should receive their first dose as soon as possible after the vaccine becomes available to allow the second dose (which must be administered ≥4 weeks later) to be received by the end of October.
• Community vaccination programs should balance maximizing the likelihood of persistence of vaccine-induced protection through the season with avoiding missed opportunities to vaccinate or vaccinating after onset of influenza circulation occurs. Efforts should be structured to optimize vaccination coverage before influenza activity in the community begins. Vaccination should continue to be offered as long as influenza viruses are circulating and unexpired vaccine is available. To avoid missed opportunities for vaccination, providers should offer vaccination during routine health care visits and hospitalizations. No recommendation is made for revaccination (i.e., providing a booster dose) later in the season of persons who have already been fully vaccinated.

And now we have to be concerned with flu and SARS-CoV-2, which is why we again have some new recommendations this season:

• Influenza vaccination programs might need to adapt and extend the duration of vaccination campaigns to accommodate stay-at-home orders and social distancing strategies aimed at slowing the spread of SARS-CoV-2. These circumstances might necessitate consideration of starting vaccination campaigns earlier (i.e., as soon as vaccine is available, which can be as early as July or August) to allow sufficient time to vaccinate the population and avoid some persons going unvaccinated for influenza.
• When possible, such considerations should be balanced against the potential waning of protection from influenza vaccination, particularly for persons aged ≥65 years.

Most importantly, remember that the CDC doesn’t actually say to wait until the end of October. They say to get vaccinated by the end of October. Getting your kids vaccinated as soon as you can is the best way to make sure that happens.

Could getting a flu shot early leave your kids unprotected at the very end of flu season?

Maybe, but that’s typically when flu activity is low.

If you wait, it’s also possible that COVID-19 cases will start to peak and it will become harder to get a flu vaccine. So your family could end up unvaccinated and unprotected if you wait too long to get a flu vaccine this year.

What to Know About the Best Time to Get a Flu Vaccine

Experts say to get vaccinated by the end of October. Getting your kids vaccinated as soon as you can is the best way to make sure that happens.

More on the Best Time To Get a Flu Vaccine

• Hosting a Flu Clinic During the COVID-19 Pandemic
• The Second COVID-19 Wave Might Not Be COVID-19
• How Long Does It Take for the Flu Vaccine to Start Working?
• Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2006)
• Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (2010)
• MMWR – Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2019–20 Influenza Season
• MMWR – Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2020–21 Influenza Season
• When should I get the influenza vaccine?
• Ask the Experts about Flu Vaccines
• Flu Facts vs. Fiction
• Why Get A Flu Shot?
• Why A Flu Shot Every Year?
• Study – Decline in influenza vaccine effectiveness with time after vaccination, Navarre, Spain, season 2011/12