CDC, FDA say Americans don't need booster shots as Pfizer pushes 3rd dose

WASHINGTON (Sinclair Broadcast Group) — Pfizer BioNTech kicked off the debate over booster shots with a Thursday announcement that they planned to seek U.S. authorization for a third COVID-19 shot in the coming weeks.

The company pointed to data suggesting immunity may wane after six months and booster would potentially increase protection against the virus and new variants. But U.S. health agencies and immunologists pushed back, saying the evidence does not support the need for booster shots at this time.

In a joint statement Thursday, the Food and Drug Administration and Centers for Disease Control and Prevention shot down the idea, explaining that the available vaccines have proven effective so far.

"Americans who have been fully vaccinated do not need a booster shot at this time," the agencies asserted.

The CDC and FDA noted they were weighing all the data, not just the studies provide by drug companies. The current evidence shows the Pfizer and Moderna mRNA vaccines and the one-dose Johnson & Johnson shot are effective against severe disease and death, including from variants, they wrote. "We are prepared for booster doses if and when the science demonstrates that they are needed."

The World Health Organization, which is struggling to help provide initial doses to the world's most vulnerable, was also skeptical about booster doses. In a statement to CNN, the WHO said there was "limited data available on how long the protection from current doses lasts and whether an additional booster dose would be beneficial and for whom."

In its announcement, Pfizer cited clinical and real-world data suggesting a decline in efficacy six months after vaccination. The Israeli Health Ministry recently released data indicating the Pfizer vaccine efficacy dropped to 64% in preventing COVID-19 infections and symptomatic disease. Protection against hospitalization and severe disease remained high, roughly 93%. The reduction in efficacy coincided with the increased prevalence of the delta and other variants.

"That is why we have said, and we continue to believe that it's likely, based on the totality of the data we have to date, that a third dose may be needed within 6 to 12 months after full vaccination," the company wrote in a memo.

Pfizer noted that a booster shot, give six months after the second dose of the original vaccine, provided a five to tenfold increase in neutralizing antibodies against the original SARS-CoV-2 virus. The company also announced it was developing a booster specifically targeting the spike proteins on the highly contagious delta variant.

Both Pfizer and Moderna have been publicly discussing booster shots for months. Pfizer CEO Albert Bourla even suggested an annual COVID vaccine might be necessary, like the flu shot. But much of that talk is likely premature.

There are two basic reasons to give a booster dose, explained Dr. William Moss, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health. One is if there is waning immunity, the other is is because a particular variant emerges that evades the immunity produced by current vaccines.

"We have not yet seen—that I am aware of—any evidence from the Pfizer, Moderna vaccines or even the Johnson & Johnson vaccine, of more breakthrough infections or severe disease in people who are fully immunized," Moss noted. "In other words, these vaccines seem to continue to be protective against severe disease."

Moss said of Pfizer's push for a third shot, "It's hard not to think that maybe there's a little bit of self-interest here."

There have been breakthrough infections. Well over 10,000 COVID-19 fully vaccinated people have gotten COVID-19, mostly mild or asymptomatic illness. According to CDC data, fewer than 0.004% of the people who have been vaccinated have been hospitalized or died as a result of COVID-19. At least a quarter of deaths and hospitalizations were unrelated to the virus.

Virtually all hospitalizations and deaths now occur in unvaccinated people. Infections in communities with low vaccination rates increased week over week as the delta variant has come to account for over 50% of new cases.

There is evidence that the delta variant has reduced the efficacy of the Pfizer vaccine to prevent mild to moderate COVID-19 by as much as 30% but its efficacy was diminished by less than 4% against serious illness. Some experts say the effect is not significant enough to cause alarm.

Dr. Sharon Frey, a member of the CDC's Advisory Committee on Immunization Practices (ACIP) and clinical director of the Center for Vaccine Development at Saint Louis University Medical School, agreed that existing data did not support the need for boosters. "There’s no evidence against declining protection at this time," she recently told CNBC.

Additional doses may be recommended for some subsets of the population, like the immunocompromised or older people, who typically produce fewer of the cells needed for a robust immune response.

Talk of a booster shot could also be self-defeating and complicate the efforts to get as many people as possible immunized with their first and second doses.

It has already proven difficult to meet immunization targets. The U.S. fell short of President Joe Biden's July Fourth goal of getting 70% of Americans at least one dose of the vaccine. It was also shy of having 160 million Americans fully vaccinated by that date.

The White House anticipated both goals would be reached by the middle of the month. But parts of the country lag with low rates of vaccine uptake and high hesitancy.

Nearly one-third of adults have not been vaccinated and 13 states have less than 50% of their population fully vaccinated. Most of the 170 counties with the highest case rates, have fewer than 40% of their residents vaccinated. People under 25 continue to have the lowest vaccination rates of any age group.

"It's important in our country that we get more people first and second doses than that we get third doses right now," said Moss.

The FDA and CDC's rejection of the need for a booster was likely making a similar point, that the public health focus should not shift away from the challenge of getting people vaccinated immediately.

A third shot raises logistical challenges and medical questions about whether people who received a Johnson & Johnson or Moderna shot could or should receive a Pfizer booster.

White House COVID-19response coordinated Jeff Zients emphasized the administration's singular public health goal: "Get more and more Americans fully vaccinated...Every shot matters; every individual that we vaccinate is progress."

The debate over boosters has again raised the question that has puzzled researchers and public health officials since the start of the vaccine campaign: How long will immunity last?

"The real definitive answer to that question is, it's just going to take time and there will be variability to this," said Dr. Moss.

Several studies and real-world evidence have demonstrated the Pfizer, Moderna and Johnson & Johnson vaccines provide protection for at least six months and likely longer.

The National Institutes of Health found people who contracted COVID-19 naturally developed lasting "immune memories" at least eight months after recovering from the illness. After eight months, 95% of study participants still had significant levels of antibodies, which recognize the virus and neutralize it, as well as T cells, that help recognize and kill pathogens, and B cells, that make new antibodies. The study suggested the potential that vaccines could produce similarly long-lasting immunity.

Another study suggested that the immunity against COVID-19, once developed, could last for years or even a lifetime—though it hasn't been proven definitively.

A 2020 study published in the journal Nature suggested that people immunized with mRNA vaccines had "persistent" immune responses. Researchers indicated that certain immune cells might survive in the bone marrow of people who were infected and later vaccinated, able to create antibodies whenever they're needed.

Another study indicated that memory B cells continued to strengthen for at least a year after infection.

"It’s a good sign for how durable our immunity is from this vaccine," Ali Ellebedy, an immunologist at Washington University in St. Louis, who led the study told The New York Times.

Another recent Nature study found that people infected by SARS, which is similar to the SARS-CoV-2 virus, had long-lasting memory T cells that were reactive to the virus 17 years after infection.

The hope is that both the mRNA and adenovirus vector vaccines (J&J and AstraZeneca) could produce long-lasting immune responses, similar to other vaccines. New variants could change the picture if they evolve in a way that evades that response.