Studies show many people may not need a fourth COVID-19 booster for several months, or even years

• Studies show that 3 vaccines may be enough to protect against coronavirus variants for a long time.
• An expert told the New York Times that they’re seeing diminishing returns from additional doses.
• Medical officials are still considering the official guidance around additional boosters in the US.

If you recently got a booster shot to protect against COVID-19, you may not need another for several months, or even several years, new studies suggest. 

According to one study released earlier this week and reported on by Apoorva Mandavilli for The New York Times, receiving three mRNA vaccinations from Pfizer-BioNTech or Moderna helps the body create a wide array of antibodies that are especially effective in not only preventing death and severe illness, but also in protecting against variants. 

John Wherry, director of the Institute for Immunology at the University of Pennsylvania, told the New York Times that scientists are “starting to see now diminishing returns on the number of additional doses,” noting that a fourth vaccination may be unnecessary to protect against death and serious illness for the average adult. 

The NYTimes also cited at least four studies that found that the immune system — using specialized T cells produced by the vaccines or after an infection — is capable of remembering and attacking the virus after several months and may even be able to do so for many years. 

It’s not impossible to imagine this outcome since scientists have already observed this exact response in individuals infected with the SARS coronavirus.  

In the case of SARS, a study found that individuals exposed to the virus during the 2003 outbreak still carried T cells that could remember and target the virus more than 17 years later. Health officials believe this may also be the case with COVID-19. 

Still, the data is inconclusive as experts continue to gather more information. The studies come as medical officials consider guidance around additional boosters, a discussion that Dr. Anthony Fauci, President Joe Biden’s chief medical advisor, said in December was “too premature.” 

“One of the things that we’re going be following very carefully is what the durability of the protection is following the third dose of an mRNA vaccine,” Fauci said in December. “If the protection is much more durable than the two dose non-boosted group, and we may go a significant period of time without requiring a fourth dose.”

However, experts say vulnerable demographics like the elderly and immunocompromised may benefit from a fourth shot. Countries like Sweden and Israel have been among the first to offer the additional booster to high-risk communities.