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Here's Why You Need Both COVID-19 Vaccine Doses

Date:2021-01-28 click:0

Pfizer’s COVID-19 vaccine, BNT162b2, is finally here. Just three days after the FDA granted Emergency Use Authorization (EUA), U.S. health care professionals began receiving their first shots. (Those in long-term care facilities are expected to start receiving theirs next week.)
The key thing to note: This vaccine has two shots. To be fully effective—we’re taking about that 95 percent efficacy— you have to take them both, three weeks apart. According to a Pfizer fact sheet, after the first dose, you will be given a vaccination card. This card, which you must bring back with you, tells you when to come in for that second shot.
It is being reported that last Friday Florida Governor Ron DeSantis said that a single dose of the vaccine may provide enough protection against COVID. Orlando Sentinel’s story read that DiSantis reportedly said: “Just get as many doses out there…I’m not sure that Pfizer would agree or FDA would agree, but I think just the point is, getting that first does out really does make a difference, and I think you’ll see that.”

The first dose does do something, but not everything we need it to. While research shows that the initial dose has a 52 percent efficacy, that figure comes with a caveat. Per FDA documents, “the efficacy observed after Dose 1 and before Dose 2, from a post-hoc analysis, cannot support a conclusion on the efficacy of a single dose of the vaccine.” That’s because the trial didn’t have a single-dose arm, the document goes on to explain. Meaning, it didn’t study that.
“Efficacy does not equal effectiveness, although they are related,” says Daniel B. Fagbuyi, MD, an emergency physician and an Obama Administration Biodefense and Public Health Appointee. “A single vaccine dose may have efficacy of 50 to 60 percent in clinical trials, but in the real world the effectiveness could potentially be less than 50 percent and would not provide significant immunity necessary to adequately protect the patient or resolve this pandemic.”

Pfizer’s BNT162b2 may not signal a clear end to the pandemic, especially since it will take several months before vaccinations will be widely available, but it is a significant step in the battle against COVID-19. But you have to take both doses