Citing New Data, Pfizer Outlines Case for Booster Shots


Pfizer reported on Wednesday that the power of its two-dose Covid vaccine wanes slightly over time, but nonetheless offers lasting and robust protection against serious disease. The company suggested that a third shot could improve immunity, but whether boosters will be widely needed is far from settled, the subject of heated debate among scientists.

So far, federal health officials have said boosters for the general population are unnecessary. And experts questioned whether vaccinated people should get more doses when so many people have yet to be immunized at all.

“There’s not enough evidence right now to support that that is somehow the best use of resources,” said Natalie Dean, a biostatistician at Emory University in Atlanta.

Still, the findings raise questions about how well the Pfizer vaccine will prevent infection in the months to come. And with coronavirus cases surging again in many states, the data may influence the Biden administration’s deliberations about delivering boosters for older people.

In the new study, the researchers followed the volunteers for six months after vaccination, up to March 13. Over the entire period, the researchers estimated, the vaccine’s efficacy was 91.5 percent against symptomatic Covid-19. (The study did not measure the rate of asymptomatic virus infections.)

But within that period, efficacy did gradually drop. Between one week and two months after the second dose, the figure was 96.2 percent. In the period from two to four months following vaccination, efficacy fell to 90.1 percent. From four months after vaccination to the March cutoff, the figure was 83.7 percent.

Those figures still describe a remarkably effective vaccine, however, and may not convince critics that booster shots are widely needed.

The study comes on the heels of data from Israel suggesting that the Pfizer-BioNTech vaccine’s protection may be waning there. But experts have pushed back against a rush to approving a booster there. The data have too many sources of uncertainty, they say, to make a precise estimate of how much effectiveness has waned. For example, the Delta-driven outbreak hit parts of the country with high vaccination rates first and has been hitting other regions later.

“Such an analysis is still highly uncertain,” said Doron Gazit, a physicist at Hebrew University who analyzes Covid-19 trends for the Israeli government.

Earlier on Wednesday, Pfizer reported that a third dose of its vaccine significantly increases blood levels of antibodies against several versions of the virus, including the Delta variant.

Results were similar for antibodies produced against the original virus and the Beta variant, which was first identified in South Africa. Pfizer and BioNTech expect to publish more definitive research in the coming weeks.

The announcement was a preliminary snapshot of data contained in an earnings statement. And although antibody levels are an important measure of immunity, they are not the only metric. The body has other defenses that turn back infection.

Pfizer also said in its statement that vaccines for children ages 5 through 11 years could be available as early as the end of September. The vaccine is already authorized in the United States for everyone ages 12 and up.

Pfizer’s vaccine brought in $7.8 billion in revenue in the last three months, the company said, and is on track to generate more than $33.5 billion this year.

The vaccine is poised to generate more sales in a single year than any previous medical product, and by a wide margin. Pfizer did not disclose its exact profits on the vaccine, but reiterated its previous estimate that its profit margins on the vaccine would be in the high 20 percent range. Even if the drugmaker’s profits fall on the lower end of that range, that would work out to about $3 billion in profit so far this year.

Rebecca Robbins contributed reporting.



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