Johnson & Johnson's single-shot vaccine proves effective in trial, but less so than Moderna, Pfizer

Johnson & Johnson COVID-19 Vaccine
Posted at 8:11 AM, Jan 29, 2021
and last updated 2021-01-29 17:59:12-05

Johnson & Johnson says its single-shot COVID-19 vaccine is effective in preventing severe cases of COVID-19, but not as well as the other two-shot vaccines that are already on the market.

The company released results from its Phase 3 trial on Friday, saying that it was 66% effective overall at preventing moderate to severe cases of the virus and 85% effective in preventing the most severe cases of COVID-19.

"The big number that is really important is that they had no cases of hospitalizations and deaths in their vaccine arm," said USF Health associate professor Dr. Michael Teng.

By contrast, two-shot vaccines made by Pfizer and Moderna were both more than 90% effective in preventing COVID-19. But Dr. Teng explains the difference in effectiveness between all the vaccines isn't something people should worry about. Instead, he says we have to keep our eye on the big picture, that with the vaccine, you're going to get immunity to the virus.

“If we weren’t spoiled by the mRNA vaccines, we would have been jumping up and down having a 72 percent efficacious vaccine, that’s a single shot, that’s cheap to produce, and relatively it's easy to produce. This is a fantastic vaccine," said Teng.

Results from safety data did not report any significant safety concerns or see any severe, life-threatening allergic reactions. The company explained the vaccine is estimated to last for two years at -4°F, at least three months of which can be at about refrigerator temperature.

Because the Johnson & Johnson shot only requires a single dose, a large supply of the vaccine could potentially solve some logistical problems in widespread distribution.

"You only have to go get it once," said Dr. Teng. "You don’t have to make an appointment for three or four weeks later. You don’t have to take off time from work to get another dose. You go in and get it once, and you’re done."

Johnson & Johnson also said that the vaccine candidate performed better in the U.S. than it did in South Africa, where a mutated form of the virus is spreading throughout the country. According to the Associated Press, the vaccine was 72% effective in preventing moderate to severe cases of COVID-19 in the U.S., while only 57% effective in South Africa.

The company says it plans to file for Emergency Use Authorization in early February and expects to have doses available to ship immediately. Johnson & Johnson has already committed to providing 100 million doses of the vaccine by June and could provide doses as soon as it is cleared by the CDC and FDA.