COVID-19 Booster: What You Need To Know

COVID-19 vaccine and band-aid on arm

UPDATED 11/30/21

Infectious disease experts Jessie Leyse, MD, of UVM Health Network – Central Vermont Medical Center and Tim Lahey, MD, MMSc, of UVM Medical Center tackle the top questions about COVID-19 booster vaccines.

Why do I need a booster of the COVID-19 vaccine?

Although COVID-19 vaccination remains effective in preventing severe disease and death, studies show that protection against the virus may decrease over time and not be as effective against more contagious variants. According to the Centers for Disease Control and Prevention (CDC) “emerging evidence also shows that among healthcare and other frontline workers, vaccine effectiveness against COVID-19 infections is decreasing over time,” likely due to those same factors.

If boosters are needed, does that mean the vaccines aren’t working?

No. COVID-19 vaccines were intended to prevent severe illness, hospitalization and death – and they are very successful at that. People who have been vaccinated have several times lower risk of infection, but that protection is not perfect. Some vaccinated people do still get infected. Importantly, vaccines protect people from hospitalization and death, and that protection is better than the protection they get from infection. That means that some people who would have ended up in the ICU sick from COVID-19 instead get a mild cold or not sick at all. 

As more time passes after vaccination, however, the amount of protection from COVID-19 infection and disease appears to shrink a little. Being vaccinated is still much better than being unvaccinated. 

Booster shots – which are given for many vaccines – are designed to bring the level of protection back up to the very high levels seen at the outset.

Will the COVID-19 vaccine protect me from breakthrough infection?

Even after COVID-19 vaccination, breakthrough infections can happen. However, infections are happening much less frequently in vaccinated people than in unvaccinated people. Plus, breakthrough infections tend to produce mild symptoms with dramatically fewer complications. The COVID-19 vaccine is your best protection against serious illness, hospitalization and death. 

Update: The omicron variant

At this point, a lot remains unknown about omicron, from how sick people will get to whether the current vaccine formulas will work against it. As scientists gather more information over the next month, we should learn a lot more.

Experts expect the vaccines will work, according to infectious disease specialist Tim Lahey, MD. “Right now the best protection is the same as for delta or any other variant: Get vaccinated,” says Dr. Lahey. It’s vaccination that keeps people from getting seriously ill or dying, he says. He also points out that omicron is a reminder that if you’re indoors, in public or around people not in your household, it’s a good idea to wear a mask.

Who is eligible for a booster shot?

The CDC and FDA have approved and recommend Pfizer and Moderna boosters if you are 18+ and completed your two-dose regimen at least six months ago. Johnson & Johnson boosters are available if you are 18+ and received your first dose at least two months ago.

Additional populations may be recommended to receive a booster shot as more data become available.

Can I get my flu shot at the same time?

Yes. The CDC has announced that the flu and COVID-19 vaccines can now be given at the same time. There is no need to delay either of the vaccines as they are safe to be administered within any time period of each other. According to the CDC, it is important to maintain routine vaccinations throughout the COVID-19 pandemic to prevent illnesses that lead to unnecessary medical visits and hospitalizations, which further strain the healthcare system. 

How do I schedule a booster appointment?

For Vermont: Visit the Vermont Department of Health website or call 855-722-7878. To reduce your wait time on the phone, we recommend calling during regular business hours.

For New York: Find a COVID-19 vaccine near you by searching on, texting your ZIP code to 438829 or calling 1-800-232-0233. You can also visit the New York Department of Health website to register.

Should I bring my COVID-19 vaccination card to my appointment?

Yes, bring this card to your booster vaccine appointment. If you did not receive a COVID-19 Vaccination Record card at your first appointment, or have misplaced it, contact the vaccination site where you got your first shot or your state health department to find out how you can get a card.

For more information about COVID-19 vaccination and eligibility, visit our COVID-19 vaccine resource page.

 Stay Informed

Sign up to receive the latest stories, information and guidance from our experts on a wide variety of health topics.