2021-09-16 03:35:00 Study of Covid Booster Shot Benefits Fans Debate Over Extra Doses
Study of Covid Booster Shot Benefits Fans Debate Over Extra Doses
In an acrimonious debate over booster doses, Israeli researchers reported on Wednesday that a third dose of the Pfizer-BioNTech coronavirus vaccine can prevent infections and severe illness in adults over the age of 60 for at least 12 days.
The study, which was published in the New England Journal of Medicine, is the latest salvo in the debate over whether booster doses are necessary for healthy adults and whether they should be given out, as the Biden administration intends, when so much of the world remains unvaccinated.
According to several independent scientists, the available data suggests that only older adults will require boosters — and even then, they may not be necessary.
Vaccination continues to be a powerful preventative measure against severe illness and hospitalization in the vast majority of people, according to experts. However, the vaccines appear to be less effective against infections in people of all ages, particularly those who have been exposed to the highly contagious Delta variant.
The Israeli data show that a booster can improve protection in older adults for a few weeks — a result that experts say is unsurprising and does not indicate long-term benefit.
“What I predict will happen is that the immune response to that booster will increase, and then it will contract again,” Marion Pepper, an immunologist at the University of Washington in Seattle, predicted. “But is that three- to four-month window what we’re aiming for?”
Federal health officials, including Dr. Anthony S. Fauci, President Biden’s top pandemic medical adviser, have justified plans to distribute booster shots by citing emerging evidence from Israel and other countries indicating that immunity from vaccination fades over time.
The idea has sent some Americans scrambling for booster shots even before they are formally authorized, a step that the Food and Drug Administration may take as soon as Friday. Even among government scientists, however, the idea has been met with skepticism and outrage.
Two scientists who lead the Food and Drug Administration’s vaccine branch announced their departure this fall, citing their dissatisfaction with the administration’s push for booster doses before federal researchers could review the evidence.
On Monday, an international group of scientists, including former FDA officials, condemned the push for boosters. The scientists analyzed dozens of studies in their review, which was published in The Lancet, and concluded that the world would be better served by using vaccine doses to protect the billions of people who are still unvaccinated around the world.
“Our primary goal here in this pandemic was, first and foremost, to avoid, to end all preventable deaths,” said Dr. Soumya Swaminathan, World Health Organization chief scientist and co-author of The Lancet review. “And, given that we have the tools to do so very effectively, we should be using them to save lives all over the world.”
To prevent the virus from mutating into even more dangerous forms than the Delta variant — and possibly into one that evades the immune response entirely — experts say the more pressing need is to protect the unvaccinated, both in the United States and elsewhere.
The World Health Organization has asked world leaders to hold off on distributing boosters at least until the end of the year, with the goal of immunizing 40% of the global population. However, some high-income countries have already begun to provide boosters to their citizens, and others may follow suit.
On Tuesday, British scientists recommended that adults over the age of 50 and other medically vulnerable people in the country receive a third dose. France, Germany, Denmark, and Spain are also considering or have begun administering boosters to older adults. Israel has authorized boosters for anyone over the age of 12 and is already considering fourth doses for its citizens.
Based on the health records of more than 1.1 million people over the age of 60, the Israeli team collected data on the effect of booster shots for the new study. The researchers discovered that at least 12 days after the booster, rates of infection were elevenfold lower and rates of severe disease nearly twentyfold lower in those who had received a booster compared to those who had only received two doses.
The researchers admitted that their findings were preliminary. “At this point, we cannot predict what will happen in the long run,” said Micha Mandel, a statistics and data science professor at the Hebrew University of Jerusalem.
9:48 p.m. ET on September 15, 2021
The question is scientifically complex, in part because preventing infection is a very different goal than preventing hospitalization and death.
Antibodies are the body’s first line of infection defense. Vaccines are unlikely to provide long-term protection against infections because the antibodies they stimulate the body to produce inevitably decline over time, according to scientists.
However, the immune system’s cellular branch is the body’s heavy armament against hospitalization and death. Immune memory encoded in this branch can take a few days to kick in, but it can last for months after the initial immunization.
Some scientists argue that this is the problem with the booster strategy: the tools to prevent hospitalization and death are already available. If the goal is to prevent infections, the country will be trapped in an endless cycle of booster shots.
“If you really use infection as an outcome, you probably need a booster every six months, which is unrealistic and unattainable,” said Dr. Peter Chin-Hong of the University of California, San Francisco. “I’m not interested in symptomatic disease; I’m interested in severe disease.”
He added that the only vaccinated patients he has seen in the hospital are immunocompromised patients or adults over the age of 70 who also have other health issues.
Dr. Fauci and other health officials have cited Israeli data showing an increase in severe illness among vaccinated people of all ages in citing the need for boosters. However, combining all age groups can statistically inflate the rates.
Only people over 60 show a significant drop in efficacy against severe illness when the Israeli figures are broken down by age, according to Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center and a former Biden administration adviser.
Understand Vaccine and Mask Requirements in the U.S.
Vaccination is the law.
The Food and Drug Administration granted full approval to Pfizer-coronavirus BioNTech’s vaccine for people aged 16 and up on August 23, paving the way for mandate increases in both the public and private sectors. Vaccines are increasingly being mandated for employees by private companies. Such mandates are legally permissible and have been upheld in court.
Mask is supreme. In July, the Centers for Disease Control and Prevention recommended that all Americans, regardless of vaccination status, wear masks in indoor public places within outbreak areas, reversing previous guidance issued in May. See where the CDC guidance would apply, as well as where states have implemented their own mask policies. Masks have become a point of contention in some states, with some local leaders defying state bans.
Universities and colleges
Over 400 colleges and universities require students to be immunized against Covid-19. Almost all of them are in states that supported Vice President Biden.
Schools. Vaccine mandates for educators have been implemented in both California and New York City. According to an August survey, many American parents of school-age children oppose mandatory vaccines for students, but are more supportive of mask mandates for students, teachers, and staff members who do not have their shots.
Hospitals and medical facilities
Many hospitals and major health systems are requiring Covid-19 vaccinations for their employees, citing rising caseloads caused by the Delta variant and persistently low vaccination rates in their communities, including within their own workforce.
The city of New York. Workers and customers must show proof of vaccination for indoor dining, gyms, performances, and other indoor situations, though enforcement does not begin until September 13. Teachers and other education workers in the city’s vast school system will be required to receive at least one vaccine dose by September 27, with no option for weekly testing. Employees at city hospitals must also get vaccinated or undergo weekly testing. New York State employees are subject to similar rules.
On a federal level. The Pentagon announced that coronavirus vaccinations would be made mandatory for the country’s 1.3 million active-duty troops “no later” than the middle of September. President Biden announced that all civilian federal employees would be required to be vaccinated against the coronavirus or face regular testing, social distancing, mask requirements, and travel restrictions.
“We’ve known for a long time that vaccines elicit less robust immune responses in the elderly,” Dr. Gounder explained. “Recommending additional vaccine doses for the elderly is not controversial.”
Other differences in vaccination campaigns in Israel and America raise concerns about whether the new findings apply to citizens of both countries. For example, more than 90% of Israelis over the age of 50 have been immunized, and older adults are more likely to be hospitalized for Covid-19.
On Wednesday, FDA scientists acknowledged this limitation, saying that studies conducted in the United States “may most accurately represent vaccine effectiveness in the United States population.”
So far, research in the United States indicates a decline in vaccine efficacy against severe illness only in older adults. Except in adults over 75, the ability of the vaccines to prevent hospitalizations barely changed after the arrival of the Delta variant, according to three studies published last week by the C.D.C.
An ongoing study of the Pfizer-BioNTech vaccine shows a drop in efficacy against symptomatic infection from 95% in the first two months to 84 percent four to six months after the second dose.
However, other Pfizer data, also released on Wednesday, showed that the vaccine’s efficacy against severe disease remained constant at 97 percent.
Pfizer said in a statement, “We remain confident in the protection and safety of the two-dose vaccine.” “However, we remain optimistic that a booster dose can be used to maintain as high a level of protection as possible over time.”
Some scientists argue that for older people, a decline in infection protection is a compelling argument for boosters. “In that group, one would always want to be proactive rather than reactive,” Dr. Chin-Hong said.
Michel Nussenzweig, an immunologist at Rockefeller University, said he wanted the booster shot (he’s 66), but also supported its use in the general population to break up transmission chains.
Although immunity in younger people is still strong, an extra dose that prevents infections would limit the virus’s spread to unvaccinated people around them, he said.
“It will eventually prevent others from going to the hospital, and it will eventually benefit the way the country is going,” he added.
Other experts questioned that premise, claiming that there is no evidence that the transmission drop would be significant enough to justify boosters.
Researchers said that in younger people, officials must weigh the limited benefit of a third dose against the risk of side effects such as blood clots or heart problems. According to Dr. Pepper, repeatedly stimulating the body’s defenses can lead to a condition known as “immune exhaustion.”
“There is obviously some risk in trying to ramp up an immune response indefinitely,” she said. “If we get into this cycle of boosting every six months, this could work against us.”