COVID-19 vaccine: When does protection begin?


COVID-19 vaccine: When does protection begin?

One common question many people have about the COVID-19 vaccine centers around when it becomes effective and how many doses are needed.
Three highly effective versions of the COVID-19 vaccine have been authorized for use in the U.S. The Johnson & Johnson vaccine requires a single dose, while the Moderna and Pfizer/BioNTech vaccines require two doses spread several weeks apart to be most effective.

When does the vaccine become effective?

In the case of the Pfizer/BioNTech and Moderna vaccines, a limited amount of data suggests people may begin to benefit from some level of protection from COVID-19 after receiving the first dose of the vaccines. In clinical trials, the vaccine developed by Pfizer/BioNTech was found to be 52 percent effective at preventing COVID-19 during the three-week period between first and second doses.
However, it’s unclear how complete that protection is or how long it might last. That’s one of the reasons public health officials say it’s important to follow through with the second dose.
In clinical trials, both the Pfizer/BioNTech and Moderna vaccines were shown to be approximately 95 percent effective at preventing COVID-19 after the second dose. The Pfizer vaccine was measured to reach that effectiveness seven days after the second dose; Moderna’s vaccine was measured to reach that effectiveness 14 days after the second dose.

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“The first dose essentially primes the immune system to recognize the virus,” says Dr. William Jackson Epperson, medical director of primary care at Tidelands Health, our region’s leader in COVID-19 vaccination. “The second dose is necessary to prompt a strong immunological response and affords you maximum protection against the virus.”
In the case of the one-dose Johnson & Johnson vaccine, the CDC considers people to be fully vaccinated two weeks after receiving the vaccine. In clinical trials, the Johnson & Johnson vaccine was found to be 66 percent effective at preventing illness from the disease, but – most importantly – 85 percent effective at preventing severe COVID-19 illness and 100 percent effective at preventing hospitalization from COVID-19.

Immunity takes time

It’s important for people to remember the process of building immunity takes time, Dr. Epperson says. That means you could be infected with COVID-19 just before or just after vaccination. If that happens, the vaccine did not give you the virus. Rather, you contracted the virus before your body had a chance to build sufficient immunity.
“We’re strongly encouraging people to get the vaccine as soon as possible,” Dr. Epperson says. “By receiving the vaccine, you can help protect yourself and your loved ones from COVID-19 and help our community, state and nation recover from the pandemic.”

Temporary symptoms

He noted that some people may experience temporary symptoms such as soreness, fatigue or headache after receiving the COVID-19 vaccine. Such symptoms are common after receiving a vaccine and indicate the body is responding the way it’s supposed to. Because of the rigorous vaccine safety measures in place, serious adverse reactions to vaccines are rare.

Get your COVID-19 vaccine

Make a vaccination appointment at Tidelands Health today by calling 1-833-6-MYSHOT (1-833-669-7468) or receive your vaccine by simply walking in during regular hours of operation at one of the health system’s three COVID-19 vaccination clinics. Learn more by clicking here. 

Even after receiving the vaccine, it’s important to continue taking precautionary measures such as wearing masks, social distancing and avoiding large crowds until a large portion of the population is vaccinated and more information is available about how long the vaccine affords protection from COVID-19, Dr. Epperson says.
“We’ve reached a turning point in the battle against COVID-19,” Dr. Epperson says. “But we all have to do our part by continuing to follow protective measures and by getting the vaccine when it becomes available to us.”

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