By Peter Loftus and Thomas M. Burton
U.S. health regulators authorized the first single-dose Covid-19 vaccine, according to people familiar with the matter. The shot from Johnson & Johnson promises to boost a mass-vaccination campaign rushing to end the deadliest pandemic in more than a century.
The vaccine’s authorization, the third issued by the U.S. Food and Drug Administration, will give health authorities a desperately needed new source of doses as they scramble to ramp up inoculations ahead of elusive emerging strains.
Shipments are expected to start within a day or two, which could mean the first doses will be administered the coming week. The FDA authorized the vaccine’s use in adults.
The shot’s addition to the country’s vaccination drive comes at a precarious moment in the pandemic in the U.S. Newly reported cases, hospitalizations and deaths have been dropping in recent weeks, but remain higher than peaks seen last summer and spring.
Also, new variants are spreading. More than 2,100 cases linked to variants first identified in the U.K., South Africa and Brazil have now been detected in the U.S., according to the Centers for Disease Control and Prevention.
J&J’s shot wasn’t as effective in studies as two Covid-19 vaccines, from Pfizer Inc. and Moderna Inc., that have been previously authorized. It also didn’t work as well against at least one new strain of the virus — the one first identified in South Africa — as against the original strain of the virus.
Health authorities say J&J’s vaccine still works well, and are encouraging eligible people to get whatever shot they can.
Also, the vaccine showed preliminary signs, according to J&J, of curbing spread of the virus among people who don’t show symptoms. They have been a significant source of transmission.
J&J’s single-dose shot could greatly simplify the vaccination drive, which has been complicated by the need to give two doses, three or four weeks apart, as required by the two vaccines cleared earlier.
The J&J vaccine also has more favorable temperature requirements for distribution and storage, making it easier for sites, including many in rural areas, that lack expensive freezers to give the shots.
Some studies have shown that the Pfizer and Moderna vaccines provide good protection after just one shot, but the research is ongoing and regulators haven’t signed off on any change.
Likewise, the Pfizer and Moderna vaccines can be stored for longer at higher temperatures than was initially thought, but storage and handling of J&J’s shot will still be easier. Pfizer’s vaccine can be stored in a regular refrigerator for five days, while J&J’s can stay there for at least three months.
Limited initial supplies, however, will probably blunt any early impact from the addition of the newly authorized shot. J&J expects to have just 4 million doses ready to ship right away. The company has said it would deliver 20 million doses by the end of March.
J&J expects output will quickly increase, so that the company can deliver a total of 100 million doses for use in the U.S. by the end of June.
Like other leading Covid-19 vaccine developers, J&J compressed a process that normally takes years into months. The FDA, likewise, moved relatively quickly to authorize the shot’s use.
The agency turned to an emergency-use authorization process created by federal law to deal with situations like the current global pandemic.
The FDA’s standard review, resulting in an approval, usually takes months. Yet the agency said it still held J&J’s vaccine to virtually the same kinds of standards for safety and effectiveness it would normally require.
The FDA based its decision on a study of about 44,000 volunteers 18 years old and older.
The study found J&J’s vaccine was 66.1% effective at protecting people from developing moderate and severe cases of Covid-19 at least 28 days after vaccination, and was generally safe.
Its overall effectiveness, however, wasn’t as high as that from the first two vaccines to be authorized in the U.S. Shots from Pfizer and partner BioNTech SE and from Moderna were more than 94% effective in their late-stage studies.
And the J&J vaccine appeared to be less effective against the South Africa variant. Other Covid-19 vaccines also have shown less potency against virus variants. South Africa began rolling out the J&J…