‘We tend to forget that we are in an arms race with this virus.’
NEW HAVEN, Conn. — Boosters are for the best, according to a new study. Researchers from Yale University and the University of North Carolina at Charlotte report that viral protection against COVID-19 following a person’s initial vaccination is only short-lived. Study authors say their findings stress the importance of opting for a third and even fourth shot.
This project is the first ever to quantify the chances of contracting COVID following either a previous infection or vaccination by the Moderna, Pfizer, Johnson & Johnson, or Oxford-AstraZeneca vaccines.
The research team found that the risk of a “breakthrough infection” (testing positive for COVID-19 after being vaccinated) depends on the type of vaccine. Current mRNA vaccines (Pfizer, Moderna) offer the longest duration of protection. Incredibly, those mRNA vaccines can protect an individual nearly three times as long as either natural infection and/or the Johnson & Johnson and Oxford-AstraZeneca vaccines.
“The mRNA vaccines produce the highest levels of antibody response and in our analysis confer more durable protection than other vaccines or exposures,” says lead study author Jeffrey Townsend, the Elihu Professor of Biostatistics at Yale School of Public Health, in a university release. “However, it is important to remember that natural immunity and vaccination are not mutually exclusive. Many people will have partial immunity from multiple sources, so understanding the relative durability is key to deciding when to provide a boost to your immune system.”
How can you stay protected against reinfection?
Study authors say stay up to date on the latest booster shots. The vaccines are constantly being updated to better address and protect against evolutionary changes seen in the coronavirus.
“We tend to forget that we are in an arms race with this virus, and that it will evolve ways to evade both our natural and any vaccine-derived immune response,” adds co-study leader Alex Dornburg, an assistant professor at the University of North Carolina at Charlotte. “As we have seen with the Omicron variant, vaccines against early virus strains become less effective at combating new strains of the virus.”
Study authors put together a data-driven model assessing infection risk over time. This approach allowed the team to take advantage of the notably similar reinfection probabilities between endemic coronaviruses (common colds) and SARS-CoV-2 (the virus responsible for COVID-19). Those similarities greatly assisted the research team in making longer-term projections than earlier studies focused only on current-day infections. Their innovative model also facilitated the placement of antibody responses following natural and vaccine-mediated immunity into the same context, thus enabling much easier comparisons.
“SARS-CoV-2 mirrors other endemic coronaviruses that also evolve and reinfect us despite natural immunity to earlier strains,” Townsend concludes. “Continual updating of our vaccinations and booster shots is critical to our fight against SARS-CoV-2.”
The study is published in the journal Proceedings of the National Academy of Sciences.