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Johnson & Johnson's single-dose vaccine protects against COVID-19, analysis finds

Last Updated Feb 24, 2021 at 4:16 pm EDT

Johnson & Johnson’s single-dose vaccine protects against COVID-19, according to an analysis by U.S. regulators Wednesday that sets the stage for a final decision on a new and easier-to-use shot to help tame the pandemic.

Food and Drug Administration scientists confirmed that overall the vaccine is about 66 percent effective at preventing moderate to severe COVID-19, and about 85 percent effective against the most serious illness. The agency also said J&J’s shot is safe.

That’s just one step in the FDA’s evaluation of a third vaccine option for the U.S. On Friday, the agency’s independent advisers will debate if the evidence is strong enough to recommend the long-anticipated shot. Armed with that advice, FDA is expected to make a final decision within days.

The vaccination drive has been slower than hoped, hampered by logistical issues and weather delays even as the country mourns more than 500,000 virus-related deaths.

So far, about 65 million Americans have received at least one dose of vaccine made by Pfizer or Moderna, shots that require two doses several weeks apart for full protection.

J&J tested its single-dose option in 44,000 people in the U.S., Latin America, and South Africa.

Because different mutated versions of the virus are circulating in different countries, researchers analyzed the results geographically. J&J previously announced the vaccine worked better in the U.S. — 72% effective against moderate to severe COVID-19, compared with 66% in Latin America and 57% in South Africa.


RELATED: Canada to ramp up vaccine rollout with over 600,000 doses arriving this week


In Canada, federal health officials provided an updated vaccine forecast last week, estimating that by the time summer arrives the country could see over half of its residents inoculated.

Best-case forecasts consider vaccine deliveries from J&J, AstraZeneca, and Novavax, in addition to the already approved Pfizer-BioNTech and Moderna shots.

The forecast estimates 64 percent of the population could be fully vaccinated by the end of June if the other three vaccines get approval from Health Canada.

Canada has an order placed for 10 million doses of the yet-to-be-approved J&J vaccine, with options to purchase 28 million more.

The J&J vaccine can last three months in the refrigerator which makes it easier to handle than the Pfizer and Moderna vaccines, which must be kept frozen.

The AstraZeneca vaccine is made similarly to J&J’s and can be refrigerated but still takes two shots instead of the single-dose.

Last week, Canada’s deputy chief public health officer said that health officials were looking into evidence that a single dose of the Pfizer shot could be as effective as a double dose

Original data suggested one dose gave around 50 percent more protection against the virus while two doses gave about 95 per cent protection. Experts are now saying that was measured from the moment the vaccine was given instead of waiting two weeks to let the immune system gear up.

Executives with Pfizer-BioNTech and Moderna said they’re ramping up their supply of COVID-19 vaccines, with shipments expected to double and potentially triple in the coming weeks.

This week Canada is receiving its biggest combined shipment yet of vaccines from both distributors.


RELATED: Pfizer, Moderna executives expect vaccine shipments to triple in weeks ahead


While the overall effectiveness numbers may suggest the J&J candidate isn’t quite as strong as two-dose competitors, all of the world’s COVID-19 vaccines have been tested differently, making comparisons nearly impossible. While it wouldn’t be surprising if one dose turns out to be a little weaker than two doses, policymakers will decide if that’s an acceptable trade-off to get more people vaccinated faster.

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. That vaccine is made with similar technology as J&J’s but initially was developed as a two-dose option until beginning a one-dose test in the fall.

If the FDA clears the J&J shot for U.S. use, it won’t 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 be producing around a billion doses by the end of the year.


With files from Lauran Neergaard and Matthew Perrone of the Associated Press

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