J&J said on Friday that the single-vaccine vaccine in the US and seven other countries was 66% effective in preventing moderate to severe diseases, and much more protective – 85% – against the most severe symptoms.
There was some geographical variation. The vaccine worked better in the US – 72% effective against moderate to severe COVID-19 – compared to 57% in South Africa, where it faced a more easily spread mutated virus.
“Gambling on a single dose was definitely worth it,” said Dr. Mathai Mammen, global head of research at J & J’s Janssen Pharmaceutical Unit, told The Associated Press.
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With vaccinations worldwide, experts relied on a single-dose vaccine that would barely stock up and avoid the logistical nightmare of getting people back for boosters.
But with other competing vaccines being 95% effective after two doses, the question of whether something less protection is an acceptable consideration to get more shots in the arms quickly.
The company said it would submit an application for emergency use in the US and then abroad within a week. They are expected to deliver 100 million doses to the US by June, and they expect some to be ready as soon as the authorities give the green light.
These are preliminary findings from a study among 44,000 volunteers that has not yet been completed. Researchers have been monitoring diseases that start 28 days after vaccination – about the time when they would rather get a two-dose variety, they would still need another chance.
After day 28, no one vaccinated needed hospitalization or died, regardless of whether they were exposed to ‘regular COVID or these particularly nasty variants’, Moms said. When the vaccinated became infected, they had a milder disease.
To overcome the plague that has killed more than 2 million people worldwide, billions will have to be vaccinated. The shots that have been rolled out in different countries so far require two doses with a few weeks apart for full protection. Early data are mixed about exactly how well all the different types work, but shots made by Pfizer and Moderna look about 95% protective after the second dose.
But amid shortages, some countries have advised postponing the second dose of certain vaccines with little information on how it will affect protection.
All COVID-19 vaccines train the body to recognize the new coronavirus, usually by noticing the muscular protein it covers. But they are made in different ways.
J & J’s shot uses a cold virus like a Trojan horse to carry the pike genes into the body, where cells make harmful copies of the protein to replenish the immune system should the actual virus occur.
Rival AstraZeneca makes a similar vaccine against cold viruses that require two doses. Both the AstraZeneca and J&J vaccines can be stored in a refrigerator, making them easier to transport and use in developing countries than the frozen ones manufactured by Pfizer and Moderna.
It is not clear how well the AstraZeneca version, which is used in Britain and several other countries, works. Tests in Britain, South Africa and Brazil have suggested that two doses are about 70% effective, although there are questions about how much protection older adults receive. An ongoing U.S. study could provide more information.
J&J said the vaccine works consistently in a wide range of people: A third of participants were over 60 and more than 40% had other diseases that put them at risk of severe COVID-19, including obesity, diabetes and HIV.
J&J said the vaccine is safe, with reactions similar to other COVID-19 shots such as fever that occur when the immune system is restored.
The company said there were no serious allergic reactions, although it did not release details. But occasionally other COVID-19 vaccines cause such reactions, which can be reversed if treated immediately – and authorities have warned people to be on the lookout for any type of vaccination.
J&J has entrenched its commitment to a study of a two-dose version of the vaccine, which is still ongoing.
Friday’s interim results come on the heels of another vaccine in final testing. Novavax reported this week that the vaccine appears to be 89% effective in a British study and that it appears to work – though not as well – against new mutated versions of the virus that are spreading in Britain and South Africa. A larger study in the US and Mexico is still involving volunteers.
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