Dr Anthony S. Fauci, who heads the division of infectious diseases at the National Institutes of Health, said he was surprised by the apparent sharp drop in the effectiveness of the Pfizer vaccine that Israeli data seems to suggest. He said he wanted to compare it with data the CDC had collected from cohorts of thousands of people across the United States. “People are raising their eyebrows a bit,” he said.
As other questions abound, senior administration officials said it seemed increasingly clear that the vaccines would not grant indefinite immunity to the virus, and that boosters might be needed for at least some people maybe nine months after their first injection. The administration has already purchased more than enough vaccine to deliver the third doses of Pfizer and Moderna, and has quietly prepared to expand the distribution effort, should it become necessary.
With so little data yet public, many health officials and experts have spoken with caution about booster shots. Dr Paul A. Offit, a member of the Food and Drug Administration’s External Advisory Committee on Vaccines, said that an increase in mild or moderate cases of Covid-19 among those vaccinated does not necessarily mean that a reminder was necessary.
“The goal of this vaccine is not to prevent mild or mild, moderate infectious diseases,” he said. “The goal is to avoid hospitalization to death. At present, this vaccine has resisted that. “
The premature prospect of a third dose could also act as a deterrent to vaccination, other health experts warn. If Americans think immunity to vaccines is short-lived, they said, they might be less likely to receive their initial injection.
“We don’t want people to believe that when you talk about boosters it means the vaccines aren’t working,” Dr. Fauci said during a congressional hearing on Tuesday. “They are very effective.
Among vaccine makers, Pfizer has been particularly proactive in sharing its data with the government. But the administration was taken aback by the company’s public announcement this month that it planned to seek emergency clearance from the FDA for a recall.