Johnson & Johnson single-shot COVID-19 vaccine appears 66% effective overall in global trial

Johnson & Johnson's long-awaited vaccine appears to protect against COVID-19 with just one shot it's not as strong as some of its two-shot rivals but still potentially helpful for a world in dire need of more doses.

J&J said Friday that in the U.S. and seven other countries where their trial has been conducted, the single-shot vaccine was 66 per cent effective overall at preventing moderate to severe illness, and much more protective 85 per cent against the most serious symptoms.

There was some geographic variation. The vaccine worked better in the U.S. 72 per cent effective against moderate to severe COVID-19 compared to 57 per cent in South Africa, where it was up against an easier-to-spread mutated virus.

Dr. Matthew Oughton, an infectious diseasespecialist at Jewish General Hospital in Montreal, told CBC News the trial data "certainly looks promising for a single dose, which of course will certainly ease a lot of the logistics we've been dealing with so far with the current vaccines that have been granted approval."

He said by examining mixed populations across continents, the J&J trial is not only "looking at differences in how different groups of people respond, that also means that they capture different viral variants, so they have a good sense of the real-world efficacy of this vaccine."

With vaccinations off to a rocky start globally, experts havebeen counting on a one-dose vaccine that would stretch scarce supplies and avoid the logistics nightmare of getting people to return for boosters.

Greater protectionvs. more shots

But with some competing vaccines shown to be 95 per cent effective after two doses, the question is whether somewhat less protection is an acceptable tradeoff for getting more shots in arms quickly.

Matthew Miller, an associate professor at the Institute for Infectious Disease Research at McMaster University, told CBC News by email that the decision will depend on multiple factors, including "the procurement timelines for specific vaccines in each country" and how prevalent the newly circulating variants become.

"Some high-risk populations may need vaccines that confer higher degrees of protection, while less efficacious vaccines might be appropriate for lower-risk populations," he said.

The Canadian government signed an agreement with Johnson & Johnson for up to 38 million doses of their vaccine, though as of earlier this month, officials said a vaccine schedule had not been finalized.

WATCH \ Dr. Matthew Oughton, infectious diseases specialist, encouraged by data so far:

Johnson & Johnson vaccine 'very promising,' says infectious disease specialist

3 years ago

Duration 3:40

Calling the clinical trial 'thorough,' infectious disease specialist Dr. Matthew Oughton says Johnson & Johnson's single-shot COVID-19 vaccine is also easier to handle logistically compared to approved vaccines in Canada.

J&J said that within a week, it will file an application for emergency use in the U.S., and then abroad. It expects to supply 100 million doses to the U.S. by June, and expects to have some ready to ship as soon as authorities give the green light.

The U.S. Food and Drug Administration has set a 50 per cent threshold for any COVID-19 vaccine to be considered for emergency use authorization.

No deaths reported in the vaccine group

The J&J data comes frompreliminary findings from a study of 44,000 volunteers that isn't completed yet. Researchers tracked illnesses starting 28 days after vaccination about the time when people getting a two-dose vaccine would have needed another shot.

After day 28, no one who got vaccinated needed hospitalization or died, regardless of whether they were exposed to "regular COVID or these particularly nasty variants," Dr. Mathai Mammen, global research chief for J&J's Janssen Pharmaceutical unit, told The Associated Press.When the vaccinated did become infected, they had a milder illness.

Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, also was particularly encouraged by the findings with respect to patients with the most serious symptoms.

"This really tells us that we have now a value-added vaccine candidate," said Fauci at a Friday briefing of U.S. health officials in President Joe Biden's administration.

Defeating the scourge that has killed more than two million people worldwide will require vaccinating billions, and the shots currently being rolled out in different countriesrequire two doses a few weeks apart for full protection. Early data is mixed on exactly how well all the different kinds work, but shots made by Pfizer and Moderna appear to be about 95 per cent protective after the second dose.

But amid shortages, some countries have advised delaying the second dose of certain vaccines with little data on how that would affect protection.

Company also testing 2-shot vaccine

All COVID-19 vaccines train the body to recognize the new coronavirus, usually by spotting the spikeprotein that coats it. But they're made in very different ways.

WATCH \ Canadian labs working hard to track new variatns:

Growing concern about COVID-19 variants in Canada

3 years ago

Duration 4:15

COVID-19 numbers are falling, but Canadian health officials are becoming increasingly concerned about the presence of two coronavirus variants. A variant first found in the U.K. has been confirmed in three provinces while a variant first discovered in South Africa variant has been found in two provinces.

J&J's shot uses a cold virus like a Trojan horse to carry the spike gene into the body, where cells make harmless copies of the protein to prime the immune system in case the real virus comes along.

Rival AstraZeneca makes a similar cold virus vaccine that requires two doses. Both the AstraZeneca and J&J vaccines can be stored in a refrigerator, making them easier to ship anduse in developing countries than the frozen kind made by Pfizer and Moderna.

J&J said its vaccine works consistently in a broad range of people: A third of participants were over age 60, and more than 40 per cent had other illnesses putting them at risk of severe COVID-19, including obesity, diabetes and HIV.

Vaccine producers need to be 'nimble': Fauci

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 revved up.

"Gambling on one dose was certainly worthwhile," saidMammen, but J&J hashedged its bets with a study of a two-dose version of its vaccine, which is still underway.

While it released few details, the company said there were no serious allergic reactions. But occasionally other COVID-19 vaccines trigger such reactions, which can be reversed if promptly treated and authorities have warned people to be on the lookout regardless of which type of vaccine is used.

A handful of coronavirus variants have gained attention in recent weeks, a development that Fauci and the new director of the Centers for Disease Control described as one to be expected.

"I think we should be treating every case right now as if it's a variant," said the CDC's Dr. Rochelle Walensky.

"We will continue to see the evolution of mutants," saidFauci. "We will have to be nimble to adjust to make versions of the vaccine that are actually specifically directed to whatever mutations are prevalent at the time."

Friday's interim results come on the heels of another vaccine in final testing. Novavax reported this week that its vaccine appears 89 per cent effective in a U.K. study, and that it also seems to work though not as well against new mutated versions of the virus circulating in Britain and South Africa. A larger study in the U.S. and Mexico is still enrolling volunteers.