Good news about the Pfizer-BioNTech, Moderna and J&J COVID-19 vaccines

Results of a large study conducted in Israel show that after a two weeks, a single dose of the Pfizer-BioNTech COVID-19 vaccine is 62% effective at preventing severe cases of the disease.

The Pfizer-BioNTech vaccine is currently approved as a two-dose regimen, and the findings reported in the New England Journal of Medicine today (Feb. 24) show that it is considerably more effective at two doses. But the results are good enough for the single dose that they may invite some consideration of using the Pfizer-BoNTech vaccine as a single dose or, at the very least, a reason to space out the interval between the first and second doses. A longer interval between doses could speed up vaccination rates and achieve herd immunity faster.

The results reported in NEJM were based on a large study of members of Clalit Health Services, an integrated healthcare organization in Israel. The researchers matched 596,618 vaccinated members to the same number of unvaccinated members to assess the effectiveness of the vaccine in preventing a variety of different COVID-19-related outcomes.

In the abstract the researchers reported the vaccine’s effectiveness for several COVID-19-related outcomes at days 14–20 after the first dose and compared those figures to the effectiveness at seven or more days after a second dose was administered.

Here is how that comparison came out:

Moderna said in a press release today (Feb. 24) that it had completed manufacture of a version of its approved mRNA vaccine that is designed to combat the variant of the SARS-CoV-2 virus that emerged in South Africa.

The company said the tweaked vaccine, named mRNA-1273.351, had been shipped to the NIH in anticipation of starting a phase 1 trial that will involve injecting it in a small group of people to assess its safety.

The Cambridge, Massachusetts, biotech company said the tweaked vaccine may be used by itself as booster or combined into a single dose along with the company’s authorized vaccine, mRNA-1273. Moderna is calling that combined, “multivalent booster” mRNA-1273.211.

The company’s press release said it plans to evaluate mRNA-1273.351 and mRNA-1273.211 as a primary vaccination series.

The single-dose Johnson & Johnson vaccine seems likely to get an emergency use authorization (EUA_ from the FDA, perhaps early next week.

A briefing document prepared by the agency staff that was made public today (Feb. 24) that said company trial data show the vaccine is 66.1% effective against laboratory-confirmed moderate-to-severe COVID-19 and has “favorable safety profile with no specific safety concerns identified that would preclude issuance of an EUA.“

The briefing document was prepared for the much-anticipated meeting Vaccines and Related Biological Products Advisory Committee meeting on Friday (Feb. 26.) The committee’s role is advisory — the FDA has the final word on the EUA — but influential. The document that came out today is just a briefing document for the committee but the lack of any red flags points to a committee endorsement and then an agency OK early next week.