In the United States, the number of adults who have received at least one dose of the COVID-19 vaccine is now higher than the number who have not. Additionally, one in three American adults is now fully vaccinated, according to data from the Centers for Disease Control and Prevention (CDC).
With so many Americans getting vaccinated, and millions more joining them every day, it is natural to look ahead and wonder how long this protection will last.
The answer is as simple as it is unsatisfactory: nobody knows.
“We still don’t know how long immunity lasts from the vaccines that we have right now,” Dr. Katherine O’Brien, who heads the World Health Organization’s department of antigens, reported in a podcast. “We will really have to wait for time to pass to see how long these vaccines last.”
The first two antigens authorized by the Food and Drug Administration (FDA), one manufactured by Pfizer and BioNTech and the other by Moderna, began to be applied in late July as part of their phase 3 clinical trials. The second doses came three weeks later in the Pfizer-BioNTech trial and four weeks later for the other company.
After the second dose, it takes two more weeks for the immune system to achieve full protection. That means the first people to get fully immunized hit that mark in September, about six months ago.
Vaccine manufacturers follow up on these clinical trial volunteers and test them to see if the benefits of the injections have remained stable or if they have started to wane. So far, they both look strong.
As of April 1, the number of people who were at least six months after their second dose of Pfizer-BioNTech had exceeded 12,000, and they are still seeing “high vaccine efficacy,” according to Albert Bourla, CEO of Pfizer. .
Among all trial participants, the antigen has been 91.3% effective in preventing COVID-19 cases as of March 13, Pfizer and BioNTech said in a statement. That figure rose to 92.6% for the United States participants, and the vaccine was at least 95.3% effective in preventing severe cases of coronavirus.
The companies said they plan to publish more detailed data in a peer-reviewed medical journal soon.
Moderna said in a statement last week that its vaccine was more than 90% effective in preventing all types of COVID-19 and more than 95% effective in preventing severe cases of the disease among participants in its clinical trials. About half of those people were at least six months after the time the antigen took full effect.
Additionally, blood tests from 33 people who participated in the first phase of Moderna’s clinical trial showed that antibodies to the coronavirus remained prevalent six months after receiving their second vaccine. Those results were published this month in the New England Journal of Medicine.
Only time will tell how long this effect will last.
Meanwhile, both companies are working on booster shots that would boost a weakened immune system. Some of those doses are designed to better protect against new coronavirus variants that have emerged since the original vaccines were created.
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