Taking two doses of the vaccine produces a strong immune response that reduces the risk of severe disease by more than 90%, with protection from mild and asymptomatic infections gradually eroding.
That’s why Pfizer has asked and received US Food and Drug Administration authorization to add boosters for many people who are six months out from vaccination.
“I think we expect immunity to gradually decrease over time, but that’s not a reason for people to panic,” said Dr. Ann Falci, a specialist in viral respiratory diseases at the University of Rochester School of Medicine.
“It’s not that suddenly one day you become completely susceptible, like you were before vaccination,” said Falci, who is helping lead clinical trials of Covid-19 vaccines.
“The vaccines all stand very well — Pfizer, Moderna and Johnson & Johnson — for serious disease,” Falci told CNN. “Now, that’s not to say that we can’t eventually get to the point where we really need people to get boosters to prevent more serious disease. But, really, most of the breakthrough infections are colds, probably Flu-like illness – not the dreaded diseases we were facing before. So my main message is, don’t panic. You’ll be fine.”
That hasn’t stopped Americans from coming to get boosters. This past week more people were getting booster shots than those receiving the first round of the coronavirus vaccine. As of Friday, more than seven million Americans had received booster shots of the third round of vaccination, authorized for those who did not get an adequate response to the first two shots.
An Israeli study involving 4,800 health care workers found antibody levels decreased rapidly after two doses of the vaccine, “particularly in men, in individuals 65 years of age or older, and in individuals with immunosuppression.” “
A second study from Qatar showed that protection from the Pfizer vaccine peaked in the first month after vaccination and then begins to decline.
In a report published in the New England Journal of Medicine, the team wrote, “These findings suggest that a substantial portion of the vaccinated population may lose their protection against infection in the coming months, perhaps increasing the potential for new pandemic waves.” “
How can protection from mild or asymptomatic infections decrease while staying strong against serious illness?
This is because the human immune system is complex.
Antibodies form the first line of defense by stopping the virus from getting into certain cells of the body. It is this protection that starts deteriorating over time.
But there is a second line of defense – cell-based immunity. Cells called B cells and T cells may take longer than antibodies, but they provide a longer, comprehensive defense against infection and are responsible for the reduction in serious infections.
So while people may be vulnerable to mild illness after vaccination, they are much less likely to actually get sick, end up in the hospital, or die.
“But there are many reasons why people don’t want to get sick. They don’t want to give it to their loved ones. People don’t want to give it to young children who can’t be vaccinated yet,” Falci told .
The US Centers for Disease Control and Prevention has been saying for months that so even fully vaccinated people need to take precautions against infection – wearing a mask when there are lots of other people who may or may not be vaccinated, especially at home. inside, and make sure the rooms are well ventilated.
“They just don’t need to storm into pharmacies and panic.”
People who are now getting boosters should have been vaccinated first in January, February and March. These include people 65 years of age and older, adults at risk of serious illness, and people with occupations or living conditions that put them at higher than average risk of infection.
Everyone else should let it cool for now.
“They just don’t need to come to pharmacies and panic,” Falci said.
Fauci told a White House briefing last month that people should not go ahead and get a booster dose for six months after their last dose of Pfizer vaccine, because they will not get the best immune response.
“For example, there would be a temptation for people who have recently been vaccinated to not wait for a six-month period,” Fauci said. But waiting several months to promote early vaccination helps generate a stronger response. The cells of the immune system that help restore weakened immunity respond more strongly if they are allowed to go into a resting state after the first round of vaccination.
That said, most people should plan to get a booster eventually, Falci said.
“Probably that’s going to be true for any vaccine, not just Pfizer — we would benefit from boosting immunity. That’s not the same as saying it’s seriously needed,” she said.
While people recovering from the infection have some protection, they are even more protected if they get vaccinated.
“I think that, based on your own natural immunity because you think you’re a strong person, is like playing Russian roulette,” Falci said.
Even young, healthy-looking people have become seriously ill with COVID-19 and died from it.
“I will never depend on my natural immunity to deal with this virus. It’s a very bad actor,” Falci said.