FDA says single-dose shot from J&J prevents severe COVID

According to an analysis released by U.S regulators, Johnson & Johnson's single-dose vaccine against severe cases of the coronavirus - as the long-anticipated shot could offer the nation a third option to help speed vaccinations by requiring a single dose, rather than two.

Scientists from the Food and Drug Administration confirmed that the vaccine is about 66% effective at preventing moderate to severe coronavirus symptoms, and 85% effective against the most serious illness - determining J&J's shot to be safe.

The analysis is just one step in the FDA’s evaluation. On Friday, the agency’s independent advisers will debate if the evidence is strong enough to recommend the shot. With that advice, the FDA is expected to make a final decision within days.

The COVID-19 death toll in the U.S. topped 500,000 this week, and the vaccination drive has been slower than hoped, hampered by logistical and weather delays. So far, about 44.5 million Americans have received at least one dose of vaccine made by Pfizer or Moderna, and nearly 20 million of them have received the second dose required for full protection.

Tests showed the Pfizer and Moderna vaccines were 95% effective at protection against symptomatic COVID-19.

The FDA said effectiveness and safety were consistent across racial groups, including Black and Latino participants.

All of the world’s COVID-19 vaccines have been tested differently, making comparisons nearly impossible. It would not be surprising if one dose turned out to be a little weaker than two doses, and policymakers will decide if that’s an acceptable trade-off to get more people vaccinated faster.

J&J has another large study underway to see if a second dose of its vaccine works better, raising the prospect that countries could eventually add a booster if one turned out to be warranted.

Like other COVID-19 vaccines, the main side effects of the J&J shot are pain at the injection site and flu-like fever, fatigue and headache. No study participant experienced the severe allergic reaction, called anaphylaxis, that is a rare risk of some other COVID-19 shots, although one experienced a less serious reaction.

The FDA said there were no serious side effects linked to the vaccine so far, although it recommended further monitoring for blood clots. In the study, those were reported in about 15 vaccine recipients and 10 placebo recipients, not enough of a difference to tell if the vaccine played any role.

J&J was on track to become the world’s first one-dose option until earlier this month. Mexico announced it would use a one-dose version from China’s CanSino, which is made with similar technology as J&J’s shot but initially was developed as a two-dose option until beginning a one-dose test in the fall.

The Pfizer and Moderna vaccines now being used in the U.S. and numerous other countries must be kept frozen, while the J&J shot can last three months in a refrigerator, making it easier to handle. AstraZeneca’s vaccine — widely used in Europe and Britain — is made similarly and also requires refrigeration but takes two doses.

If the FDA clears the J&J shot for U.S. use, it will not boost vaccine supplies significantly right away. Only a few million doses are expected to be ready for shipping in the first week. But J&J told Congress this week that it expected to provide 20 million doses by the end of March and 100 million by summer.

European regulators and the World Health Organization also are considering J&J’s vaccine. Worldwide, the company aims to produce around a billion doses by the end of the year.