A new study published in Nature offers good news for those who recovered from COVID-19 and were then vaccinated with a mRNA vaccine – a booster may not be needed.
A new study published in Nature offers good news for those who recovered from COVID-19 and were then vaccinated with a mRNA vaccine – a booster may not be needed.
The study focused on the vaccine from Pfizer-BioNTech but experts believe the results are applicable to both. This new mRNA technology set off an immune reaction in recipients that could protect for years, possibly even for life.
“It’s a good sign for how durable our immunity is from this vaccine,” said Ali Ellebedy, an immunologist at Washington University in St. Louis who led the study, which was published in the journal Nature.
After a report that people who had been infected and then recovered from the novel coronavirus had immune cells in the bone marrow for at least eight months, Ellebedy’s team dove in further to look into the more durable memory cells.
The lymph nodes house a specialized germinal center after infection or vaccination. The center is comparable to an elite boot camp, where B cells are trained and grow stronger to fight the infection should it return. The B cells are even able to learn to recognize and thwart variant strains of the virus over time.
“Everyone always focuses on the virus evolving — this is showing that the B cells are doing the same thing,” said Marion Pepper, an immunologist at the University of Washington in Seattle. “And it’s going to be protective against ongoing evolution of the virus, which is really encouraging.”
Memory B cells circulate in the bloodstream for years, even decades. Then the immune system can activate these fighters any time the invading virus returns to lock on and mark the pathogens for destruction.
The publishing team took samples from 14 people who had received the Pfizer-BioNTech vaccine, 8 of whom had recovered from coronavirus prior to vaccination. Samples were taken from the lymph nodes starting at three weeks and ending at 15 weeks after the volunteers’ first dose.
Even at four months, the team found the germinal centers highly active. The number of memory B cells had not diminished.
Typically, germinal centers peak a week or two after vaccination, then quickly wane from there. By four to six weeks out, not much is left.
But this study showed that the germinal centers activated by the mRNA vaccines are still going months after receiving the shot, without signs of diminishing.
Based on this, those who had a COVID-19 infection prior to vaccination may not need a booster at all. Those with weakened immune systems, older adults or those on medications that suppress immunity may need a booster. In theory, immunity could last a lifetime.
“Anything that would actually require a booster would be variant-based, not based on waning of immunity,” said Deepta Bhattacharya, an immunologist at the University of Arizona. “I just don’t see that happening.”
This study focused on the mRNA vaccines. For the one-shot from Johnson and Johnson, infectious disease experts are suggesting the possibility of a booster of either Pfizer or Moderna’s vaccines due to the increasing rate of delta infections. Canada is already recommending a booster for those who’ve received the AstraZeneca-Oxford vaccine.
According to the CDC, “The need for and timing of COVID-19 booster doses have not been established. No additional doses are recommended at this time.”
