What Happens If I Get COVID-19 Between Vaccine Doses?

Someone receiving a vaccine injection.

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Key Takeaways

  • You are not fully vaccinated if you have had only one dose of the Pfizer-BioNTech or Moderna vaccine.
  • If you get COVID-19 after your first vaccine dose, isolate for 10 days after you first had symptoms or a positive test.
  • Get your second dose after you have recovered from COVID-19. Aim for as close to the originally-planned date as possible.

If you’ve only had your first dose of a two-dose COVID-19 vaccine (Pfizer-BioNTech or Moderna), you aren’t yet fully protected against COVID-19.

Is it possible to get COVID-19 between the two doses? Experts say yes, but CDC data shows it happens in fewer than 2% of cases.

You are fully vaccinated two weeks after your second dose. Until then, you haven’t reached the full level of protection.

“It is possible to get COVID-19 between the first and second doses of the mRNA vaccines,” says William Moss, MD, MPH, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health.

Getting COVID-19 between doses doesn’t mean you need to restart the series. You can still get a second dose. Here’s what to know about when to get it.

Vaccines Don't Completely Prevent COVID-19

Vaccines provide a high degree of protection from SARS-CoV-2, the virus that causes COVID-19. Even so, they aren't 100% effective. It’s still possible to get COVID-19 whether you've had one dose or two. 

Based on clinical trials, the Pfizer-BioNTech vaccine is 95% effective at preventing COVID-19. The Moderna vaccine is 94.1% effective.

Data shows that infection may be more likely if you've only had one dose.

“Centers for Disease Control and Protection (CDC) reported that among 2,479 individuals who were fully vaccinated with two doses of mRNA vaccines, there were three SARS-CoV-2 infections, whereas among 477 individuals with only one dose of mRNA vaccine, there were eight confirmed SARS-CoV-2 infections,” says Inci Yildirim, MD, PhD, pediatric infectious diseases specialist at Yale Medicine in Connecticut.

Still, the first dose does reduce the risk of severe disease.

“The first dose should provide some protection, particularly against severe COVID-19," Moss says. "So your symptoms should be less than someone who was not vaccinated at all."

Booster shots are also available for all adults ages 18 and over. Vaccine protection can decline over time. The virus can also change, which is what causes variants to emerge. A booster shot adds to your protection.

There is no data yet to confirm exactly how long your immunity lasts if you have been vaccinated and you have had COVID-19. Experts recommend a booster shot if it has been six months or longer since your two-dose vaccine (Pfizer-BioNTechor Moderna). You can also get a booster shot two months or more after your one-dose vaccine (Johnson & Johnson).

Isolate and Reschedule

If you get COVID-19 before your second dose, you need to reschedule and recover first. It’s important that you isolate for 10 days, starting the day after:

  • the day of your positive test result or
  • the day you first had symptoms

“Available data from clinical trials indicate that those who had SARS-CoV-2 infection can safely get COVID-19 vaccines," Yildirim says. "CDC recommends deferring vaccination until the individuals recover completely and they have completed their isolation period. Rescheduling the second dose may be needed, but testing is not recommended."

If you have a health condition that has weakened your immune system, check with your healthcare provider to see when to get another dose, she adds.

After you recover, you still need to get the second dose to be fully protected. Health experts don't know how long your body's natural protection lasts after an infection. That's because people's immune systems respond differently to infection.

Plan to get the second dose as close as possible to the original schedule. That means 21 days after the first dose for the Pfizer-BioNTech and 28 days after Moderna. 

“If this is not feasible, CDC recommends the second dose of either vaccine can be administered up to six weeks after the first dose,” Yildirim says.

There isn’t much research about how effective vaccines are if the second dose is given after six weeks. That's why it's best if you stay within that time frame.

There is one important exception. “If you were treated with monoclonal antibodies or convalescent plasma when you had COVID-19, you should wait 90 days to be vaccinated,” Moss says.

The 90-day waiting period is a CDC precaution. There isn't enough research to know how antibody therapy could affect your body's response to the vaccine.

If you already had your first dose, got COVID-19, and had antibody therapy, wait 90 days before the second dose.

Getting COVID-19 between doses won't make your second dose less effective, experts say.

“Studies looking at the antibody levels after vaccination among individuals with prior laboratory-confirmed SARS-CoV-2 infection showed that previously-infected persons had higher levels of vaccine-induced antibody response compared to those without a history of SARS-CoV-2 infection,” Yildirim says. “We still need to determine how these levels impact the vaccine-induced protection and how long it will last.”

What This Means for You

If you get COVID-19 before your second dose of the Pfizer-BioNTech or Moderna vaccine, you need to isolate for 10 days after your positive test or your first symptoms.

Reschedule your second dose no later than six weeks after your first shot. You should still complete your vaccine doses even if you've gotten COVID-19.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Thompson MG, Burgess JL, Naleway AL, et al. Interim estimates of vaccine effectiveness of BNT162b2 and mRNA-1273 COVID-19 vaccines in preventing SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers — eight U.S. locations, December 2020–March 2021. MMWR Morb Mortal Wkly Rep. 2021;70:495–500. 10.15585/mmwr.mm7013e3

  2. Centers for Disease Control and Prevention. Pfizer-BioNTech COVID-19 vaccine overview and safety

  3. Centers for Disease Control and Prevention. Moderna COVID-19 vaccine overview and safety.

  4. Centers for Disease Control and Prevention. Quarantine and isolation.

  5. Centers for Disease Control and Prevention. Interim clinical considerations for use of COVID-19 vaccines currently authorized in the United States.

By Carla Delgado
Carla M. Delgado is a health and culture writer based in the Philippines.