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Vaccines are a valuable tool in protecting us from COVID-19. But it’s still possible to become ill with COVID-19, even if you’ve been vaccinated. These are called breakthrough infections.

Two of the three COVID-19 vaccines in use in the United States require multiple doses. Because of this, you may be wondering what happens if you get COVID-19 between your vaccine doses.

In this article, we’ll look at how it’s possible to contract COVID-19 after your first vaccine dose and what to do if it happens to you.

There are 3 COVID-19 vaccines currently in use in the United States:

The mRNA vaccines are given as 2 doses because it was found that a single dose led to a rather weak immune response. Adding the second dose increases the immune response to the vaccine, making it more effective at protecting you against COVID-19 infection.

Because of this, even though the mRNA vaccines do provide you with some protection after a single dose, it’s still possible to get COVID-19 between doses.

The clinical trials for both of these vaccines evaluated vaccine efficacy after just a single dose. Let’s see what the data said.


In the clinical trial for the Pfizer-BioNTech vaccine, 39 people that received the vaccine got COVID-19 between doses, compared to 82 people in the placebo group.

The researchers calculated that the vaccine’s efficacy at preventing COVID-19 between the first and second vaccine doses was 52 percent.

This means that, compared to those who received a placebo injection, participants who got the Pfizer-BioNTech vaccine were roughly half as likely to get COVID-19 after a single dose.


In a document submitted to the Food and Drug Administration (FDA), researchers analyzed a small group of volunteers who only received one dose of the Moderna vaccine or a placebo. Within the first 14 days, a vaccine efficacy of 50.8 percent was reported.

But as time passes, the picture changes. Within the larger clinical trial group, only 11 people who got the vaccine contracted COVID-19 2 weeks or longer after their first dose, compared to 225 people in the placebo group.

This corresponds to a vaccine efficacy of 95.2 percent beginning 2 weeks after the first dose.


Both of the mRNA COVID-19 vaccines offer some degree of protection between doses. But it’s definitely still possible to contract COVID-19 within this timeframe.

It’s also worth noting that the clinical trials for these vaccines were done prior to the emergence of COVID-19 variants. As such, the amount of protection between doses may not actually be as high now as it was when these trials were done.

If you get COVID-19 between your vaccine doses, the Centers for Disease Control and Prevention (CDC) recommends that you delay your next dose until you’ve recovered from your illness.

Although there’s no specific time period you need to wait after recovering from COVID-19, most doctors recommend waiting at least 2 weeks.

You can receive your next dose of the vaccine when you’ve met the CDC’s guidelines for discontinuing isolation. As of writing, these guidelines are as follows:

  • Stay home. Stay home for at least 5 days after your symptoms start or after a positive COVID-19 test. Wear a mask when you need to be around others in your household.
  • End isolation. When you can end isolation depends on your specific situation:
    • If you had symptoms, you may end isolation after at least 5 full days if you’ve not had a fever for at least 24 hours and your other symptoms are starting to get better.
    • If you didn’t have symptoms, you may end isolation at least 5 full days after your positive COVID-19 test.
    • If you were very ill or have a weakened immune system, you’ll need to isolate for at least 10 days. Be sure to consult your doctor before leaving isolation.
  • Mask up. After your 5 day isolation ends, continue to wear a mask at home and in public for an additional 5 full days. During this time, don’t go to public places where you can’t wear a mask, like restaurants or gyms.

These guidelines apply to everyone, regardless of their vaccination status. So, if you got COVID-19 between vaccine doses, you can schedule your second dose after your isolation period ends.

If your isolation period causes you to miss the 3-week or 4-week interval between vaccine doses, that’s OK. In this situation, the CDC recommends that you receive your second dose as close to this window period as possible. You don’t have to restart the vaccine series.

Vaccination and certain COVID-19 treatments

If you had monoclonal antibodies or convalescent plasma to treat COVID-19, you’ll need to wait 90 days before getting your next dose. This is because these treatments may interfere with your immune system’s response to vaccination.

It’s still important to receive your second dose of the COVID-19 vaccine, even if you had to delay it due to getting COVID-19 between doses. This is because it’s still unclear exactly how long natural immunity to COVID-19 lasts.

In fact, there’s actually some newer evidence that individuals that have had COVID-19 and been vaccinated against COVID-19 may have improved immunity. This is referred to as super-immunity.

A January 2022 study explored this concept. It found that, compared to people who’d only had the vaccine, individuals who contracted COVID-19 either before or after their vaccination had a greater increase in antibodies that broadly neutralize the virus.

The protection provided by COVID-19 vaccines declines over time. While the vaccines are still very effective at protecting you from severe illness, hospitalization, or death due to COVID-19, you may be more susceptible to mild or moderate illness as your immunity wanes.

Because of this, the CDC recommends booster shots for everyone 12 years and older.

You can select a different COVID-19 vaccine as your booster, but when you’re eligible for a booster depends on the vaccine you originally received:

  • If you got a Pfizer-BioNTech or Moderna vaccine: You can get a booster at least 5 months after your initial 2-dose vaccine series. Either of the two mRNA vaccines can be used as a booster.
  • If you got a J&J vaccine: You can get a booster at least 2 months after your initial single-dose vaccine.

As with your initial COVID-19 vaccines, getting a booster is important even if you’ve already had COVID-19.

If you get COVID-19 prior to being boosted, make sure you’ve recovered and met guidelines for ending isolation before scheduling your booster.

A booster for some vaccines is completely normal. A couple of examples of vaccines that require boosters include:

None of the COVID-19 vaccines are 100 percent effective at preventing COVID-19. This is particularly true after only a single dose of the mRNA vaccines. Although the likelihood is reduced, it’s still possible to get COVID-19 between doses.

If you do get COVID-19 between vaccine doses, delay your second dose until you recover and are clear to leave isolation. Depending on which mRNA vaccine you got, try to schedule your second dose as close to the 3-week or 4-week window period as you can.

It’s important to get both your primary vaccines and a booster, even if you’ve already had COVID-19. If you ever have any questions or concerns about COVID-19 vaccines, be sure to contact your doctor.