On Wednesday, newly released data by Pfizer suggests that a third dose of the vaccine can "strongly" boost protection against the Delta variant of COVID-19. Data from the company's booster study says that people's antibody levels can jump from five- to more than 11-fold after a third dose of the Pfizer vaccine, compared to their second dose. People ages 18 to 55 who receive a booster shot might see antibody levels against the Delta variant jump five-fold, while those ages 65 to 85 might expect to see antibody levels greater than 11-fold than following a second dose. Pfizer plans to ask the Food and Drug Administration for authorization of a third dose in August, the Associated Press reports.
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Despite already lagging vaccine rates in the U.S., Biden administration health officials agreed that booster shots could be beneficial to vulnerable populations, specifically people who are 65 and older, and people with compromised immune systems who make up 2.7% of the population, according to the Centers for Disease Control and Prevention (CDC). Dr. Amanda Cohn, the chief medical officer of the CDC's immunizations division said last week that officials were "actively looking into ways" to provide booster shots to certain people "earlier than any potential change in regulatory decisions," according to The New York Times.
Moderna is currently testing a Delta-variant-specific booster shot, and Johnson & Johnson is expected to have clinical trial data on a second vaccine shot by next month, citing similar needs for additional shots. Research has found that the Pfizer vaccine becomes less effective against the coronavirus after about six months. The company's own global studies showed that four to six months after the second dose, the vaccine's effectiveness against symptomatic infections dropped from a high of 95% to 84%, The Times reported.
Data from the Israeli Ministry of Health also found the Pfizer vaccine was just 39% effective in preventing infection in late June and early July, compared to 95% from January to April. However, it remained more than 90% effective at preventing severe cases of the virus, and about the same in preventing hospitalizations.
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At this time, the major concern about the Delta variant is that it is easily spread between people, which has led to increased infections and hospitalizations, particularly among unvaccinated people, Reuters reports. Still, some public health experts remain cautious about a booster, citing that millions of people haven’t received even a first dose yet.
"The vaccines were designed to keep us out of the hospital" and continue to do so, Dr. William Schaffner, a vaccine expert at Vanderbilt University Medical Center told AP earlier this month. He cautioned that giving another dose would be "a huge effort while we are at the moment striving to get people the first dose."
Dr. Anthony Fauci warned similarly that talk of booster shots could lead people to believe that immunity from the vaccines is brief, and might deter people from getting vaccinated altogether. "We don't want people to believe that when you're talking about boosters, that means that the vaccines are not effective," he testified at a congressional hearing last week. "They are highly effective."
Right now, nearly all Americans hospitalized with COVID-19 are unvaccinated, which Dr. Monica Gandhi, an infectious diseases doctor at the University of California, San Francisco described as "pretty astounding effectiveness," when it comes to the vaccines. So whether or not a booster is approved, any form of vaccination remains the greatest protection against COVID and its variants.