It comes after studies published last month found that boosters may not be necessary for people who were previously infected with COVID-19 and vaccinated later, The New York Timesreported. For those who were previously infected and then vaccinated, the protections could last for years.
The study did not investigate 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 the Washington University School of Medicine in St. Louis, found that after a single dose of the Pfizer vaccine, immune cell responses, located in the germinal center of the lymph nodes, remained active longer than expected. This suggests that these mRNA vaccines may offer extensive protection against the virus.
Forty-one people participated in this study, some of whom had recovered from COVID-19. Scientists studied lymph node samples from 14 of them.
Researchers also found that Moderna and Pfizer vaccines provide robust protection for at least 12 weeks after a second dose and may provide low level protection for at least a year.
“The study shows that germinal centers have prolonged B-cell responses,” William Schaffner, MD, professor of preventive medicine and infectious disease at Vanderbilt University told WebMD. “The anticipation is that these memory cells will persist for a substantial period of time.”
Schaffner says that while the B cell response – a key to immune system – was not very long, the study offers some insight into the biology of what happens after someone receives an mRNA vaccine. But the results should not lead to quick conclusions.
“It’s one thing to have this assertion in the laboratory of the biology of the immune response,” Schaffner says. “It is quite another to study the duration of protection of large populations of people.
He says the findings also add to ongoing discussions about whether people who have been vaccinated will need booster shots.
“The two big issues are kind of addressed here,” Schaffner said. “One is the actual duration of protection provided from the initial vaccination. The other is that there are variants which may escape this protection. Or the antibodies we create will not specifically provide protections. “
He notes that there is optimism that none of these problems arose, even 6 months after the start of vaccine distributions.
“Studies like this suggest it could take a year or more,” Schaffner says. “It would be fabulous. “
But how long exactly immunity hard remains a question.
“The authors are very careful not to make specific projections,” Schaffner says. “It would be very difficult. “
He says that while booster shots can be a popular topic of conversation, they shouldn’t be too much of a concern, even with the current variants.
“The vaccines we have provide very good protection for the active variants,” says Schaffner. “So there is no immediate need for a booster at this time.”