How long does the COVID-19 vaccine protection last?

CINCINNATI (WKRC) – If you’re wondering how long you’re protected once you get the coronavirus vaccine, you’re not alone.

It’s one of the top questions people and researchers around the country are asking.

The CDC just announced that people who have had both doses of the Pfizer or the Moderna vaccine don’t need to quarantine after exposure to someone with COVID-19. If it’s been longer than three months since your last shot, you do, which raises the question: How long does the vaccine protection last?

Pharmacy and molecular scientists at Johns Hopkins University said there’s a lot that goes into determining how long a vaccine fights a virus.

"We have the flu vaccine where we need it yearly versus measles where you're good for a lifetime once you're fully vaccinated,” said Namandje Bumpus, Ph.D., a professor and the director of the department of Pharmacology and Molecular Sciences at John Hopkins University School of Medicine. “So, it really depends. It's very much a function of the vaccine and the nature of the virus, which makes it difficult to predict with new vaccines like the COVID-19 vaccine actually how long they will last."

Luckily, that’s not stopping people right now from wanting to get it.

“I always wanted to get this. As soon as it came out, I wanted it,” said Bill Viox, who got the vaccine. “I want to prevent the COVID.”

While on the CDC website “How long does the vaccine last?” is one of the most frequently asked questions, their answer is basically echoed around the country:

“We don’t know,” said Bumpus.

Because of the ongoing research on convalescent plasma administered from those who’ve had the coronavirus given to those who get sick to help fight the virus, we know that antibodies, which show immunity in the body, wane over time.

“Certainly people that have had COVID itself at least -- it looks like they have several months of immunity and even that's being followed,” said Bumpus. “But with the vaccine, we really just need to understand that immune response lasts."

The answer to this question is just one of many reasons those participating in vaccine trials are followed long-term.