While taking two doses of the vaccine elicits a strong immune response that reduces the risk of serious illness by more than 90%, protection from milder and asymptomatic infections gradually decreases.
Because of this, Pfizer has sought and received approval from the U.S. Food and Drug Administration to give boosters to many people who are six months after vaccination.
“I think we expect immunity to slowly wear off over time, but this is not a reason for people to panic,” said Dr. Ann Falsey, a respiratory viral disease specialist at the University of Rochester School of Medicine.
“It’s not like you’re suddenly totally vulnerable one day like you were before you were vaccinated,” added Falsey, who has been involved in leading clinical trials of Covid-19 vaccines.
“The vaccines all do pretty well – Pfizer, Moderna, and Johnson & Johnson – for serious illness,” Falsey told CNN. “That’s not to say we may not get to a point where we really need people getting boosters to prevent more serious illnesses. But in reality, most of the breakthrough infections are colds, maybe flu-like illnesses – not the scary illnesses we faced before. So my main message is don’t panic. You’ll be fine. “
That hasn’t stopped Americans from flocking to get boosters. In the past week, more people who received their first round of coronavirus vaccine received a booster. By Friday, more than seven million Americans had received a booster shot of the third round of vaccines approved for people with immunosuppressive disorders who likely didn’t respond adequately to the first two shots.
A study from Israel of 4,800 healthcare workers showed that antibody levels decreased rapidly after two doses of the vaccine, “especially in men, those 65 years of age and older, and those with immunosuppression.”
A second study from Qatar showed that protection from the Pfizer vaccine peaked in the first month after vaccination and then decreased.
“These results suggest that a large portion of the vaccinated population may lose protection from infection in the coming months, potentially increasing the potential for new waves of epidemics,” the team wrote in a report published in the New England Journal of Medicine.
How can the protection against mild or asymptomatic infections diminish and at the same time remain strong against serious illnesses?
That’s because the human immune system is complex.
Antibodies are the first line of defense and prevent a virus from entering some cells in the body. This is the protection that wears off over time.
But there is a second line of defense – cell-based immunity. Cells called B cells and T cells may take longer to form than antibodies, but they provide longer lasting, broader defense against infection and are responsible for decreasing severe infections.
However, while people can be prone to mild illness after vaccination, they are much less likely to really 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 pass it on to loved ones. People don’t want to pass it on to young children who can’t be vaccinated yet, ”Falsey said.
The U.S. Centers for Disease Control and Prevention has said for months that even fully vaccinated people must continue to take precautions against infection – wearing masks when there are many other people around who may or may not be vaccinated, especially in Interiors, and certainly the rooms are well ventilated.
“You just don’t need to storm the pharmacies and panic.”
The people who are getting boosters now should be among the first to be vaccinated – in January, February and March. This includes people aged 65 and over, adults with illnesses that put them at serious risk of illness, and people in jobs or living conditions that put them at an above-average risk of infection.
Everyone else should cool it down now.
“There’s just no need to storm the pharmacies and panic,” said Falsey.
People shouldn’t get booster doses if it’s not six months since their last dose of the Pfizer vaccine because they’re not getting the best immune response, Fauci said in a White House briefing last month.
“For example, people who have recently been vaccinated will be tempted not to wait the six months,” said Fauci. But if you wait several months after the first vaccination to boost immunization, a stronger response can be achieved. Immune system cells that help restore declining immunity are more robust when allowed to go into a dormant state after the first round of vaccination.
However, most people should plan on getting boosters at some point, Falsey said.
“Probably this applies to all vaccines, not just Pfizer – we will benefit from boosting immunity. It’s not the same as saying it’s vital, ”she said.
While people who have recovered from an infection have some protection, they are even better protected if they also get vaccinated.
“I think that depending on your own natural immunity, because you feel like a strong person is like playing Russian roulette,” Falsey said.
Young, apparently healthy people are also seriously ill with Covid-19 and have died from it.
“I would never rely solely on my natural immunity to get through this virus. It’s a very, very bad actor,” Falsey said.