TUESDAY, May 21, 2024 (HealthDay News) — (Tasrir) — People repeatedly vaccinated for COVID — the initial shots, followed by boosters and updated vaccines — generate antibodies capable of neutralizing not just COVID variants, but even some distantly related coronaviruses, researchers reported May 17 in the journal Nature.
It appears that periodic re-vaccination for COVID might cause people to gradually build up a stock of antibodies that protect them from a variety of coronaviruses, researchers concluded.
That runs counter to concerns that annual vaccinations against COVID might interfere with immune response in subsequent years, as happens with influenza jabs, researchers said.
“The first vaccine an individual receives induces a strong primary immune response that shapes responses to subsequent infection and vaccination, an effect known as imprinting,” explained senior researcher Dr. Michael Diamond, a professor of medicine with the Washington University School of Medicine in St. Louis.
“In principle, imprinting can be positive, negative or neutral,” Diamond added in a university news release. “In this case, we see strong imprinting that is positive, because it’s coupled to the development of cross-reactive neutralizing antibodies with remarkable breadth of activity.”
A first vaccination triggers the development of memory immune cells. A second similar vaccination reactivates those memory cells, which then dominate and shape the immune response to the second jab, researchers said.
In the case of the flu vaccine, imprinting has negative effects, with the memory cells crowding out new antibodies produced by the latest jab. As a result, people develop fewer antibodies against the strains in the newer vaccine.
But researchers found that imprinting actually works well with the COVID vaccine.
To assess the breadth of people’s antibodies, researchers tested them in the lab against a panel of coronaviruses. These included two Omicron variants, as well as the SARS-1 and MERS coronaviruses and another coronavirus from a species of scaly anteater.
The antibodies wound up killing off all the viruses as well as MERS, which comes from a different branch of the coronavirus family tree than the rest, researchers found.
Further experiments revealed these antibodies were so powerful and flexible due to the combination of the original and variant vaccines.
People who only got the original COVID vaccines had only weak protection against the other coronaviruses, but after an Omicron-era booster, even they had better antibodies.
The finding suggest that regular vaccination with updated COVID vaccines will give people the tools to fight off new variants as well as other related coronaviruses.
“At the start of the COVID-19 pandemic, the world population was immunologically naïve, which is part of the reason the virus was able to spread so fast and do so much damage,” Diamond said.
“We do not know for certain whether getting an updated COVID-19 vaccine every year would protect people against emerging coronaviruses, but it’s plausible,” Diamond added. “These data suggest that if these cross-reactive antibodies do not rapidly wane — we would need to follow their levels over time to know for certain — they may confer some or even substantial protection against a pandemic caused by a related coronavirus.”
