June 29, 2021 – A new study shows surprising evidence that COVID-19 vaccines from Pfizer and Moderna may offer longer-lasting immunity than thought.
It came after studies published last month found that boosters may not be needed for people previously infected with COVID-19 and later vaccinated, the New York Times reported. For those previously infected and then vaccinated, protection could last for years.
The new results, published Monday in the journal Nature, suggest that people who receive Pfizer or Moderna vaccines and have no history of COVID-19 may also have extended immunity.
The study did not look at whether there would be similar effects with the Johnson & Johnson vaccine.
The scientists, led by Ali H. Ellebedy, PhD, of the Department of Pathology and Immunology at Washington University School of Medicine in St. Louis, found that after a single dose of the Pfizer vaccine, immune cell responses persisted in the germinal center of the lymph nodes active longer than expected. This suggests that these mRNA vaccines may offer advanced protection against the virus.
41 people participated in this study, some of whom had recovered from COVID-19. The scientists examined lymph node samples from 14 of them.
The researchers also found that the Moderna and Pfizer vaccines could offer robust protection for at least 12 weeks after a second dose and could offer low protection for at least a year.
“The study shows that the germinal centers have prolonged B-cell responses,” William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University, told WebMD. “The expectation is that these memory cells will persist for a considerable period of time.”
Schaffner says that the response of B cells – a key to the immune system – didn’t take very long, but the study does provide insights into the biology of what happens after someone is given an mRNA vaccine. But the results should not lead to quick conclusions.
“This laboratory confirmation of the biology of the immune response is one thing,” says Schaffner. “It is a different matter to study the duration of protection for a sizeable population.”
He says the results also contribute to the current discussions about whether people who have been vaccinated need a booster vaccination.
“The two big issues are addressed here,” says Schaffner. “One of them is the actual duration of protection that is granted from the first vaccination. On the other hand, there could be variants that can evade this protection. Or the antibodies we produce do not offer any special protection. “
He notes that there is optimism that none of these issues have occurred, even after six months of vaccine distribution.
“Studies like this suggest it could take a year or more,” says Schaffner. “That would be fabulous.”
But exactly how long the immunity lasts remains a question.
“The authors are very careful not to make any concrete projections,” says Schaffner. “That would be very difficult.”
He says that while booster shots may be a popular topic of conversation, even with current variations, they shouldn’t be too much of a problem.
“The vaccines we have offer pretty good protection for the active variants,” says Schaffner. “A booster is therefore not required immediately.”
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William Schaffner, MD, Professor of Preventive Medicine and Infectious Diseases, Vanderbilt University.
Nature: “SARS-CoV-2 mRNA vaccines induce persistent reactions of the human germinal center”, “SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans.”
The New York Times: “Pfizer and Moderna vaccines are likely to produce lasting immunity, study results”, “Immunity to the coronavirus can last for years, scientists find.”
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