Immunity against COVID-19 Will Take Weeks after Vaccination, Experts Say

Table of ContentsView AllTable of ContentsHow Vaccine Immunity WorksSteps to Take after VaccinationSummary

Table of ContentsView All

View All

Table of Contents

How Vaccine Immunity Works

Steps to Take after Vaccination

Summary

Key TakeawaysCOVID-19 vaccinations offer immunity two weeks (14 days) after receiving the full series (one Johnson & Johnson shot or the two-shot series from Moderna or Pfizer-BioNTech).Although vaccines provide individual immunity, building population immunity against COVID-19 takes time and still requires social distancing and mask-wearing.Early studies indicate that vaccine immunity wanes over time against variants and that boosters are necessary to maintain immunity.

Key Takeaways

COVID-19 vaccinations offer immunity two weeks (14 days) after receiving the full series (one Johnson & Johnson shot or the two-shot series from Moderna or Pfizer-BioNTech).Although vaccines provide individual immunity, building population immunity against COVID-19 takes time and still requires social distancing and mask-wearing.Early studies indicate that vaccine immunity wanes over time against variants and that boosters are necessary to maintain immunity.

Vaccines have proven to be highly effective in preventing serious COVID-19 sickness.In the United States, three vaccines are available from Johnson & Johnson (single-dose), Moderna (two-dose series), and Pfizer-BioNTech (two-dose series).

By December 2021, nearly 204 million Americans—more than 72% of the population—had been vaccinated against COVID-19. More than 58 million had received their COVID-19 booster shot since August 2021.

But your body needs time to build immunity after receiving a vaccine. This article shares information about your immunity window after vaccination, steps you can take the keep from getting sick after you get your shot, and why COVID-19 boosters are necessary to stay protected.

COVID-19 Vaccines:Stay up to date on which vaccines are available, who can get them, and how safe they are.

But this “test drive” takes time. According to WorldClinic Chief Medical OfficerWilliam Lang, MD, MHA, the body doesn’t have immunity immediately after getting a vaccine.

“It takes the body time to make adequate antibodies for any vaccine,” he told Verywell.

What This Means For YouYou can consult your primary care provider about the vaccines' effects and how they impact you. Even after being vaccinated, it’s important to continue practicing COVID-19 safety precautions, like social distancing, mask-wearing, and staying home if you’re feeling ill.

What This Means For You

You can consult your primary care provider about the vaccines' effects and how they impact you. Even after being vaccinated, it’s important to continue practicing COVID-19 safety precautions, like social distancing, mask-wearing, and staying home if you’re feeling ill.

How Long Does it Take to Achieve Immunity?

When can you consider yourself fully vaccinated? It depends on which vaccine you get.

In general, you’re fully vaccinated 14 days—or two weeks—after receiving your full series of shots. If you get a single-shot vaccine (Johnson & Johnson) you’re fully vaccinated two weeks later. If you get a two-shot series (Pfizer-BioNTech or Moderna), you’re fully vaccinated two weeks after your second shot.

Why do some COVID-19 vaccines take two shots to be fully effective?

“The first time primes your body [to the virus]," Lang said. “The second time tells the body that we’re serious about this and you really need to make immunity to it.”

RecapIt’s not uncommon to need more than one dose of a vaccine for it to be effective. For instance, thehuman papillomavirus (HPV) vaccinerequires two doses for children under 15 and three doses for 15 to 26 years and immunocompromised people andhepatitis Aandhepatitis Brequire between two and four doses. The Moderna and Pfizer-BioNTech COVID vaccines require two doses for a person to be considered fully vaccinated.

Recap

It’s not uncommon to need more than one dose of a vaccine for it to be effective. For instance, thehuman papillomavirus (HPV) vaccinerequires two doses for children under 15 and three doses for 15 to 26 years and immunocompromised people andhepatitis Aandhepatitis Brequire between two and four doses. The Moderna and Pfizer-BioNTech COVID vaccines require two doses for a person to be considered fully vaccinated.

Do I Need a Booster Shot?

As the COVID-19 virus replicates and spreads, it duplicates its RNA. During this process, changes (mutations) can occur. This can result in variants, which are different versions of the same virus.

Experts recommend a COVID-19 booster for people ages 16 and older who have have been fully vaccinated. For those who received the two-dose vaccine from Pfizer-BioNTech or Moderna, boosters are recommended at least six months after receiving the second shot. People who received the single-shot vaccine (Johnson & Johnson) should consider a booster at least two months later.

RecapMore research is needed to fully understand how long COVID-19 immunity will last, but studies have shown that it can fade over time. In order to protect yourself against virus variants, like Delta and Omicron, it’s important to consider getting a vaccine booster.

More research is needed to fully understand how long COVID-19 immunity will last, but studies have shown that it can fade over time. In order to protect yourself against virus variants, like Delta and Omicron, it’s important to consider getting a vaccine booster.

According toWilliam Moss, MD, MPH, executive director of the International Vaccine Access Center at John Hopkins in Baltimore, it’s crucial that people continue wearing masks even after getting their shots.

Even after vaccination, a large percentage of the population may not be protected because the vaccine isn’t 100% effective against COVID-19.

“If 95% efficacy holds up, 5% of people who get the vaccine will not be protected after receiving vaccination,” Moss told Verywell. “That sounds like a small percentage, but when you’re vaccinating millions of people, that’s a large number of people.”

Understanding the Immunity Window

Pfizer-BioNTech and Moderna vaccines were shown to be 82% effective after the first dose.But patients shouldn’t let their guard down just because they’ve started the vaccination process because full immunity isn’t achieved until two weeks after the final shot of the series.

Moss explains that there is a likelihood that anyone can become infected with COVID-19 within that time period. However, it will depend on whether people continue to follow COVID-19 safety guidelines within the immunity window.

“How likely they are to contract COVID-19 between the two doses is a function of how intense the transmission is in that particular area,” Moss says. “The likelihood of anyone acquiring infection and COVID-19 within a three week period—that’s not uncommon because the pandemic is out of control.”

RecapVaccines aren’t perfect. Although a 95% efficacy rate is high, it means that in 5% of patients, the vaccine won’t work as well. You can still be infected as your body builds immunity, and you could still infect others. Taking safety precautions during the immunity window and when interacting with unvaccinated people will help you—and others—stay safe.

Vaccines aren’t perfect. Although a 95% efficacy rate is high, it means that in 5% of patients, the vaccine won’t work as well. You can still be infected as your body builds immunity, and you could still infect others. Taking safety precautions during the immunity window and when interacting with unvaccinated people will help you—and others—stay safe.

Three vaccines—from Johnson & Johnson, Moderna, and Pfizer-BioNTech—are available to prevent serious COVID-19 illness. Immunity is achieved two weeks after completing the full vaccination series. During this immunity window, it’s important to continue practicing COVID-19 protocols such as wearing a face covering and maintaining social distancing.

Vaccines may be less effective against some COVID-19 variants, and booster shots may be required to maintain immunity. If you received the two-shot series from Pfizer-BioNTech or Moderna, boosters are recommended after six months; for the single-dose series from Johnson & Johnson, a booster should be considered after two months.

“We’re in the midst of a terrible pandemic. Anything we can do as individuals and as a community to get us through these very hard times is going to benefit us all,” Moss says. “It’s going to decrease the burden on the healthcare system, help us get our economy back, and open up businesses that are so crucial to our society.”

Types of COVID-19 Vaccines

8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Goldberg Y, Mandel M, Bar-On YM, et al.Waning immunity after the BNT162b2 vaccine in Israel.N Engl J Med. 2021;385(24):e85. doi:10.1056/NEJMoa2114228Polack FP, Thomas SJ, Kitchin N, et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine.N Engl J Med. 2020;383(27):2603-2615. doi: 10.1056/NEJMoa2034577U.S. Food and Drug Administration.COVID-19 vaccines.Centers for Disease Control and Prevention.COVID-19 vaccinations in the United States.Centers for Disease Control and Prevention.Understanding how vaccines work.Centers for Disease Control and Prevention.Possible side effects after getting a COVID-19 vaccine.Centers for Disease Control and Prevention.COVID-19 Vaccine Booster Shots.Pilishvili T. Interim estimates of vaccine effectiveness of Pfizer-BioNTech and Moderna COVID-19 vaccines among health care personnel — 33 U. S. Sites, January–March 2021. MMWR Morb Mortal Wkly Rep. 2021;70.doi:10.15585/mmwr.mm7020e2

8 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Goldberg Y, Mandel M, Bar-On YM, et al.Waning immunity after the BNT162b2 vaccine in Israel.N Engl J Med. 2021;385(24):e85. doi:10.1056/NEJMoa2114228Polack FP, Thomas SJ, Kitchin N, et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine.N Engl J Med. 2020;383(27):2603-2615. doi: 10.1056/NEJMoa2034577U.S. Food and Drug Administration.COVID-19 vaccines.Centers for Disease Control and Prevention.COVID-19 vaccinations in the United States.Centers for Disease Control and Prevention.Understanding how vaccines work.Centers for Disease Control and Prevention.Possible side effects after getting a COVID-19 vaccine.Centers for Disease Control and Prevention.COVID-19 Vaccine Booster Shots.Pilishvili T. Interim estimates of vaccine effectiveness of Pfizer-BioNTech and Moderna COVID-19 vaccines among health care personnel — 33 U. S. Sites, January–March 2021. MMWR Morb Mortal Wkly Rep. 2021;70.doi:10.15585/mmwr.mm7020e2

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Goldberg Y, Mandel M, Bar-On YM, et al.Waning immunity after the BNT162b2 vaccine in Israel.N Engl J Med. 2021;385(24):e85. doi:10.1056/NEJMoa2114228Polack FP, Thomas SJ, Kitchin N, et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine.N Engl J Med. 2020;383(27):2603-2615. doi: 10.1056/NEJMoa2034577U.S. Food and Drug Administration.COVID-19 vaccines.Centers for Disease Control and Prevention.COVID-19 vaccinations in the United States.Centers for Disease Control and Prevention.Understanding how vaccines work.Centers for Disease Control and Prevention.Possible side effects after getting a COVID-19 vaccine.Centers for Disease Control and Prevention.COVID-19 Vaccine Booster Shots.Pilishvili T. Interim estimates of vaccine effectiveness of Pfizer-BioNTech and Moderna COVID-19 vaccines among health care personnel — 33 U. S. Sites, January–March 2021. MMWR Morb Mortal Wkly Rep. 2021;70.doi:10.15585/mmwr.mm7020e2

Goldberg Y, Mandel M, Bar-On YM, et al.Waning immunity after the BNT162b2 vaccine in Israel.N Engl J Med. 2021;385(24):e85. doi:10.1056/NEJMoa2114228

Polack FP, Thomas SJ, Kitchin N, et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine.N Engl J Med. 2020;383(27):2603-2615. doi: 10.1056/NEJMoa2034577

U.S. Food and Drug Administration.COVID-19 vaccines.

Centers for Disease Control and Prevention.COVID-19 vaccinations in the United States.

Centers for Disease Control and Prevention.Understanding how vaccines work.

Centers for Disease Control and Prevention.Possible side effects after getting a COVID-19 vaccine.

Centers for Disease Control and Prevention.COVID-19 Vaccine Booster Shots.

Pilishvili T. Interim estimates of vaccine effectiveness of Pfizer-BioNTech and Moderna COVID-19 vaccines among health care personnel — 33 U. S. Sites, January–March 2021. MMWR Morb Mortal Wkly Rep. 2021;70.doi:10.15585/mmwr.mm7020e2

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