Pfizer CEO Albert Bourla was confident in June in the ability of his company’s COVID-19 vaccine to protect against the highly contagious Delta variant.
“I feel pretty confident that it covers [este aspecto]”Bourla pointed out.
Just a few weeks later, Pfizer indicated that it would seek authorization for a booster injection after the first trial results showed that a third dose could increase protection. In late July, Pfizer and BioNTech announced findings that, about four to six months after a second dose, the efficacy of their antigen dropped to about 84%.
Bourla was quick to promote a third dose after the disappointing news, explaining that he was “very, very sure” that a booster would boost immunity levels in those inoculated.
There’s a problem: Pfizer has yet to provide conclusive evidence to support that assurance. The company lacks late-stage clinical trial results to confirm that a booster will work against variants like Delta, which now accounts for 97% of new coronavirus infections in the United States, according to estimates by the Centers for Control and Prevention. Department of Disease (CDC).
Pfizer announced its global phase 3 trial with a third dose in mid-July. The completion date for that trial is 2022. Phase 3 results are generally required prior to regulatory approval.
“We are confident in this antigen and the third dose, but we must remember that the vaccine efficacy study is still ongoing, so we need all the evidence to back it up,” said Jerica Pitts, director of global media relations. from Pfizer. The financial stakes are huge: The company announced in July that it expects $ 33.5 billion in COVID-19 antigen revenue this year.
Meanwhile, Pfizer recently noted that if a third dose couldn’t fight the Delta variant or other strains, the drugmaker is poised to create a “custom-made” vaccine in 100 days.
All of this has created a sense of confusion about what exactly will work and when. The rush from the pharmaceutical industry to recommend boosters to the public is “a little frustrating,” said Dr. Paul Offit, director of the Center for Vaccine Education at Children’s Hospital of Philadelphia. Even if a supplement is found to be safe, he explained, the US effort should focus on “inoculating people who are not vaccinated.”
In any case, booster decisions are not up to antigen manufacturers, said Offit, who advises the National Institutes of Health and the Food and Drug Administration (FDA) on vaccines.
“Pharmaceutical companies are not public health agencies; it’s not really up to them to determine when or if there should be a booster dose, ”he said. “That is the purview of the CDC.”
In fact, the CDC and FDA, the federal agencies that oversee the licensing of COVID-19 vaccines, communicated in July that fully inoculated Americans do not need a booster shot. The currently licensed antigens, from Pfizer, Moderna and Johnson & Johnson, work as they should: all three reduce the risk of COVID-19 cases serious enough to hospitalize or kill a person.
If hospitalization and fatality rates rise among those vaccinated, then it would be time to talk about boosters, Offit said, but “we are not there yet.”
The White House has joined the mixed messages: spokeswoman Jen Psaki confirmed that the United States will purchase an additional 200 million doses of Pfizer-BioNTech antigen to inoculate children under 12 years of age and for possible boosters.
Natalie Dean, a biostatistician at Emory University in Atlanta, explained that the confusion is not necessarily the fault of any one institution. Rather, he commented, “there is genuine scientific uncertainty about how well vaccines work. [existentes] against the new variant ”.
Scientists are gathering information from observational studies, outbreak investigations, and antibody response analysis.
For many Americans, the confusion has sparked an intense search for a third illicit dose, if necessary.
Angie Melton received the Johnson & Johnson vaccine against COVID-19 in April. But fears about the Delta variant led her to also receive a dose of the Pfizer vaccine.
( David Hicks for KHN)
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“I got a dose of Pfizer last week,” shared on Facebook Angie Melton, a 50-year-old mother of four. She received the Johnson & Johnson single-shot injection at a mass vaccination site in April and feared the highly contagious Delta variant could infect her and then her uninoculated 10-year-old son, who has asthma.
After consulting with friends and doctors, as well as seeing reports on combination approaches in Europe, Melton checked into the website of a local pharmacy and made an appointment to receive an injection from Pfizer. It is also scheduled for the second dose of this antigen.
“I’m trying to keep my family safe,” Melton said.
On Thursday, the FDA announced that transplant recipients and other immunosuppressed people can receive a third dose of Pfizer or Moderna vaccines to offer additional protection against the Delta variant.
Immunosuppressed patients like Sarah Keitt, who has multiple sclerosis and Crohn’s disease, expressed relief at the possibility. Keitt, a disability rights activist living in Connecticut, said her neurologist advised her to get a brace even after she received the two Moderna injections. She commented that she was eager for another dose, but still frustrated at the lack of confidence in the protection it would provide.
“If someone could definitively say that there is a 95% chance that you are protected” with a booster, Keitt mentioned, “I would love to.”
Despite widespread media reports of “breakthrough cases,” a recent data analysis by KFF found that hospitalizations and deaths are extremely rare among fully inoculated people, well below 1%.
Offit points to a recent outbreak in Provincetown, Massachusetts, in which only four of the 346 fully vaccinated people who had breakthrough infections were hospitalized with COVID-19. Two of them had underlying medical conditions and no one died.
“This antigen still does an excellent job against the Delta variant to protect people against serious and critical illness,” he noted.
However, the effectiveness of Pfizer’s vaccine against variants is still up for debate. This month, a new prepress study by the Mayo Clinic found that the product’s effectiveness against contagion dropped to 42% from January to July, as the prevalence of the Delta variant increased dramatically.
Pfizer and its partner BioNTech announced that they are developing an updated version of their antigen to target the genomic characteristics of the Delta variant.
However, the idea that a new formulation might work better is “mostly hypothetical at this point,” said Vaughn Cooper, professor of microbiology and molecular genetics at the University of Pittsburgh.
Dr. Vincent Rajkumar, a Mayo Clinic hematologist who closely studies the immune responses and antibody levels of his patients, said using the current vaccine and testing a new version seems reasonable.
There is a hypothesis that if breakthrough infections are due to a drop in antibody levels, increasing those levels will be enough, Rajkumar added. But the most troubling theory is that the Delta variant, or any other strain, might be less threatened by the antibodies that the current antigen generates.
“So unless I reinforce [anticuerpos] with a vaccine that is specific for the Delta variant, it will not work, ”Rajkumar said. Testing both hypotheses is “the right thing to do for the sake of time.”
Simultaneously, however, the push to deliver booster injections to healthy populations is premature, said Dr. Sadiya Khan, an epidemiologist and cardiologist at Northwestern University Feinberg School of Medicine. This is because, even if those who are already fully inoculated receive a third dose or a booster, the virus is still circulating among millions of unvaccinated people.
“The overwhelming majority of infections, hospitalizations and deaths occur among those who are not inoculated,” Khan said.
“Giving up a broader strategy to vaccinate the population is going to cause continuous increases,” he explained. “The potential for damage is quite great.”
This article was produced by Kaiser Health News, one of the top three operating programs of the nonprofit Kaiser Family Foundation. KHN Editor Arthur Allen contributed to this article.
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