In a new study from Washington University in St. Louis, researchers found the Pfizer and Moderna vaccines trigger an immune system response that could fend off the coronavirus for years to come.
The finding suggests that most people immunized with the mRNA vaccines may not need booster shots.
The team previously reported that immune cells that recognize the virus lingered in bone marrow for at least eight months after COVID-19 infection.
Another team found that memory B-cells continue to mature and strengthen for at least a year after infection.
Those findings suggested that immunity might last years, possibly a lifetime, in people who were infected and later vaccinated. But whether vaccination alone might demonstrate the same power was unclear.
After an infection or a vaccination, a specialized structure called the germinal center forms in lymph nodes.
This structure is where B-cells are trained. After infection with the coronavirus, the germinal center forms in the lungs. But after vaccination, the cells’ education takes place in lymph nodes in the armpits.
In the study, the team found that 15 weeks after the first dose of vaccine, the germinal center was still highly active in all 14 study participants, and that the number of memory cells that recognized the coronavirus had not dropped.
They found that the reactions continued for almost four months after vaccination, which is a good sign.
The results suggest that a vast majority of vaccinated people will be protected over the long term—at least, against the existing variants.
People who survived COVID-19 and were later immunized may also never need booster shots, experts think. However, older adults, people with weak immune systems and those who take drugs that suppress immunity may still need boosters.
More than 1 in 10 Americans have missed their second dose of a coronavirus vaccine, a troubling trend as the more infectious Delta variant that first crippled India gains a foothold in this country.
If you care about COVID vaccines, please read studies about what are the COVID-19 vaccine’s side effects? and findings of Americans have unrealistic expectations for a COVID-19 vaccine.
For more information about COVID vaccines, please see recent studies about why it takes 2 shots to make COVID-19 mRNA vaccines do their antibody-creating best and results showing that why older people must go to the front of the COVID-19 vaccine line.
The study is published in Nature. One author of the study is Ali Ellebedy.
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