Mar 17, 2022 - Health

The COVID booster debate is back

Illustration of a group of doctors examining a giant syringe
Illustration: Sarah Grillo/Axios

Pfizer says that at least some Americans will soon need a fourth shot of its coronavirus vaccine. The problem is that, if true, that may raise questions about the utility of the vaccine in the long run.

The catch: Regulators want to see more data before they're convinced another booster is necessary. If the data does show the third shot's ability to ward off severe disease drops after a few months, that may suggest Americans need a better booster.

Driving the news: Pfizer announced Tuesday that it will submit a request to the FDA for a fourth dose of its COVID vaccine to be authorized for people 65 and older.

  • In an interview on Sunday with CBS' "Face the Nation," however, Pfizer CEO Albert Bourla didn't specify which age groups he thinks will need a fourth shot — which raised plenty of eyebrows.
  • "We know that the duration of the protection doesn't last very long," Bourla said. "It is necessary, a fourth booster right now."
  • He added that protection from the third shot is "quite good" against hospitalizations and deaths, but "not that good" against infections, and that protection against infection fades relatively quickly.

The other side: "Pfizer seems to be saying that, because their vaccine isn’t very good, people need more of it. If FDA approves another dose it would make sense to use a stronger vaccine instead, like Moderna or eventually Novavax," said Cornell virologist John Moore.

  • He added that giving seniors another dose is easier to justify than authorizing additional shots for the entire population.

What they're saying: Officials will be paying close attention to effectiveness against hospitalization over time, NIAID director Anthony Fauci said in an interview.

  • Even when it comes to the common cold, "the population tends to get reinfected with the same coronavirus time after time. As a family of viruses, they don’t seem to induce very durable protection,” Fauci said.
  • “We obviously need to continue to work on the durability of protection, either by a boosting regimen…and/or perhaps using different platforms of vaccines that give a greater durability," Fauci added. "These are all things that are just under consideration."

"We’re continuing to collect and assess all available data both from our additional booster studies we started in January 2022 as well as real world evidence as it becomes available," Pfizer said in a statement.

  • "We’re in continuous, open dialogue with regulators and health authorities to help inform a COVID-19 vaccine strategy as the virus evolves."

The big picture: The debate over a fourth dose is at its outset plagued by a familiar question: Is the point of the COVID vaccines to prevent infections, or to keep people alive and out of the hospital?

  • There's limited data on how well booster shots hold up against severe disease over time, but the best data so far suggest that protection remains at pretty high levels — 78% against hospitalizations, per the CDCaround four months after receiving the shot.
  • That means it's still unclear how much anyone stands to gain by getting a fourth shot (outside of the immunocompromised, who are already authorized to get one).

Yes, but: There's plenty of emerging data that suggest protection against infection wanes pretty quickly after the third shot, and that Pfizer loses its effectiveness faster than Moderna. Experts say this is typical with vaccines.

  • Some experts think waning may have been accelerated by the Omicron variant, which the vaccine wasn't made to target.
  • "The virus has evolved profoundly, and you can only ask so much of a vaccine," said Scripps Research's Eric Topol. "The durability isn’t great, but at least we get it back up there to the highest level with a boost.”

What we're watching: Bourla told "Face the Nation" last weekend that Pfizer is trying to create a longer-lasting vaccine.

  • "What we are trying to do, and we are working very diligently right now, it is to make not only a vaccine that will protect against all variants, including Omicron, but also something that can protect for at least a year," he said.
  • Moderna is also tweaking its existing vaccine in order to provide longer-lasting protection.

The bottom line: Administering booster shots every six months or so isn't a great long-term public health strategy, particularly if it's done with the goal of preventing mild illnesses, experts say.

  • "Neither natural infection or immunization is going to protect against mild illness for a long period of time," said Paul Offit, director of the Vaccine Education Center at the Children's Hospital of Philadelphia. "We're going to have to convince people at some point ... that protection against mild illness is not a reasonable goal."
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