Johnson & Johnson begins final phase of single-shot COVID-19 vaccine study

Johnson & Johnson is beginning a huge final study to try to prove if a single-dose COVID-19 vaccine can protect against the coronavirus.

The study starting Wednesday will be one of the world's largest coronavirus vaccine studies so far, testing the shot in 60,000 volunteers in the United States, South Africa, Argentina, Brazil, Chile, Colombia, Mexico and Peru.

In August, Canada signed a deal with a subsidiary of New Jersey-based drug conglomerate Johnson & Johnson to secure up to 38 million doses of the company's potential vaccine.

A handful of other vaccines in the U.S. including shots made by Moderna Inc. and Pfizer Inc. and some in other countries are already in final-stage testing. Hopes are high that answers about at least one candidate being tested in the U.S. could come by year's end, maybe sooner.

However, U.S. health officials insist the race for a vaccine isn't cutting corners.

"We want to do everything we can without sacrificing safety or efficacy we're not going to do that to make sure that we end up with vaccines that are going to save lives," Dr. Francis Collins, director of the National Institutes of Health (NIH), told reporters.

But many vaccine specialists question whether the Food and Drug Administration (FDA) will stick to that goal under intense pressure from the current U.S. administration. President Donald Trump has consistently presented a faster timeline for a new vaccine than experts say is adequate to fully test the candidates.

"We feel cautiously optimistic that we will be able to have a safe and effective vaccine, although there is never a guarantee of that," Dr. Anthony Fauci, infectious disease chief at NIH, told a Senate committee on Wednesday.

But Trump is pushing for a faster timeline than many experts say is adequate to fully test the candidates. On Wednesday, he tweeted a link to news about the new Johnson & Johnson vaccine study and said the FDA"must move quickly."

"President Trump is still trying to sabotage the work of our scientists and public health experts for his own political ends," Sen. Patty Murray, a Democrat from Washington, said before ticking off examples of pressure on the FDA.

FDA commissioner Stephen Hahn pledged that career scientists, not politicians, will decide whether any coronavirus vaccine meets clearly stated standards that it works and is safe.

"Science will guide our decisions. FDA will not permit any pressure from anyone to change that," Hahn said. "I will put the interest of the American people above anything else."

As for the testing of vaccine candidates, Faucisaid: "There is no cutting corners."

'Build public confidence'

Meanwhile, testing of still another experimental vaccine, made by AstraZeneca, remains on hold in the U.S. as officials examine a safety question, even though studies have resumed in other countries.

Earlier this week, Vice-President Mike Pence urged state governors to "do your part to build public confidence that it will be a safe and effective vaccine."

Fauci added in the call to governors that he is confident in "a tried-and-true process" that has checks and balances built in, including an independent board evaluating the progress of each vaccine trial, as well as "the integrity of the FDA."

A recording of the call was provided to The Associated Press.

Even if the FDA were to allow emergency use of a vaccine by year's end, supplies would be limited and given first to vulnerable groups, such as health workers. Most Americans aren't likely to receive a vaccine until sometime next year.

The Centers for Disease Control and Prevention (CDC) wants states to get ready now to roll out vaccinations, which will present enormous logistical challenges. On Wednesday, the CDC was set to announce distribution of $200 million US in congressionally approved funds to help begin setting up operations.

Health and Human Services Secretary Alex Azar said the COVID-19 vaccine campaign will build on longstanding co-operation between the federal government and the states on immunizations.

Johnson & Johnson's vaccine is made with slightly different technology than others in late-stage testing, modelled on an Ebola vaccine the company created.

Unlike the three other vaccines that started late-stage testing in the U.S., it requires only one shot, not two. Despite a later start to testing than some of its competitors, Dr. Paul Stoffels, Johnson & Johnson's chief scientific officer, told reporters that the study was large enough to yield answers possibly by early next year.