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This award-winning blog supplements the articles in Hospital Infection Control & Prevention.

A Few Caveats on First COVID-19 Vaccine

By Gary Evans, Medical Writer

As COVID-19 resurges in record numbers, the recent announcement of an investigatory two-shot vaccine with a striking 90% efficacy made for a very tempting panacea to a god-awful pandemic.

The reality is that the Pfizer Inc. (NYC) and BioNTech (Mainz, DEU) data must be thoroughly analyzed and reviewed by the Food and Drug Administration, including a safety requirement to follow at least 50% of vaccine recipients for a median of two months. However, Pfizer previously began this requirement and, as this report was filed, was expecting to complete that safety requirement by the third week in November 2020. Then the company was expected to submit an Emergency Use Authorization (EUA) request to the FDA.

According to an industry news release, Pfizer’s Phase III trial enrolled 43,538 participants, with 42% having diverse backgrounds. An external, independent data monitoring committee (DMC) is reviewing the data and no serious safety issues have been observed.

“The case split between vaccinated individuals and those who received the placebo indicates a vaccine efficacy rate above 90%, at 7 days after the second dose,” the company stated. “This means that protection is achieved 28 days after the initiation of the vaccination, which consists of a two-dose schedule. As the study continues, the final vaccine efficacy percentage may vary.”

Even if ultimately proven safe against serious outcomes, the experimental vaccine causes local and systemic reactions that the normally eloquent William Schaffner, MD, frankly describes as “nasty.”

“One of the things that is characteristic of this vaccine — like shingles vaccine but worse — is that it is very reactogenic,” says Schaffner, a professor at Vanderbilt University and one of the nation’s top vaccine experts. “A lot of people get sore arms that can last a day or two. There are other people who feel rather puny for a day, with aches and pains, headaches, even a degree of fever.”

Complicating matters — in terms of getting people to return for the second dose — is that the side effects are worse after the final shot, he notes.

“It’s very reactogenic — not just locally but systemically,” he says. “Not everybody, of course, but it is a notable percentage and we will have to alert recipients to this.”

With healthcare workers designated a top priority, arrangements to immunize them in shifts may have to be done to account for possible sick staff the following day.

“You don’t want to give it to all the workers in a long-term care facility and have a third of them not come in to work the next day,” Schaffner says.

Another issue is that the vaccine must be stored in subfreezing temperatures, which could create logistical challenges for some facilities. Thus, there are a lot of unanswered questions, including the well-known safety concerns, even among healthcare workers. Feeling ill post-immunization may add to the skepticism and blunt the uptake, even if the vaccine clears the major safety hurdles.

But these temporary side-effects — if that is all they prove to be — must be weighed against the grim toll of COVID-19 death in the United States. On Nov. 11, 2020, there were 144,133 new confirmed cases of COVID-19 and 1,893 deaths in the United States, according to Johns Hopkins.

That’s a strong argument for a vaccine with 90% efficacy.

For more on this story, see the next issue of Hospital Employee Health.