COVID-19 vaccines

How Long Will a Shot of Coronavirus Vaccine Protect You?

NBC Universal, Inc.

It's still too early to tell when you may need to get a COVID-19 shot after you're fully vaccinated. Next year? The year after that? In the 2030s?

The vaccine process is complicated, and variants might throw off an already complex process of determining the vaccine's efficacy.

Dr. Davey Smith, the chief of infectious diseases and global public health at UC San Diego, told NBC 7 that there’s no way to formulate a timeline for future COVID-19 shots this early in the game.

“We just don't have enough time to figure out how long these immune responses last for these vaccines,” Smith said.

The New England Journal of Medicine published a report on Tuesday about Moderna's vaccine, saying it should offer protection from COVID-19 for at least six months. The study was based on follow-ups with dozens of people who were vaccinated during Moderna's trial phase.

In a statement last week, Pfizer mirrored the same time frame, saying its vaccine would also be effective for at least six months.

Emerging variants, however, are where things get tricky, raising concerns over whether the vaccine has a fighting chance against variations of the virus that could show up in the future. Smith said getting vaccinated plays a crucial role in that exact fight.

“The more people that get vaccinated, the less chance for those variants to spread within the community,” Smith said.

Smith said vaccinations serve an even greater role than curbing the spread of variants: They can prevent variants from forming in the first place.

"If we can decrease that amount of time that the virus has to learn about us, the less variation or the less number of variants will arise,” Smith said. “Variations can thwart the process.”

The studies into these vaccines will remain ongoing in determining exactly how long the vaccines are able to last in offering up immunity.

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