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Johnson & Johnson's one-shot COVID-19 vaccine grants lasting response in early study

Riley Griffin, Bloomberg News on

Published in News & Features

Moncef Slaoui, the chief scientific adviser to the U.S.’s Operation Warp Speed vaccine development and distribution effort, said Wednesday that he anticipates J&J’s one-shot vaccine will show 80% to 85% effectiveness against COVID-19. J&J and its government partners can’t see the data for the time being, a standard measure to prevent bias.

Experts have said that a single-shot vaccine offers advantages: ease of distribution and administration. Vaccines from Moderna Inc., AstraZeneca Plc, and the Pfizer Inc.-BioNTech SE partnership all require two shots, which means repeat shipping and clinic visits. While Pfizer-BioNTech’s shot must be frozen, J&J’s shot can be stored at refrigerator temperatures for three months.

“A single dose is going to be so much more effective in the world,” Stoffels said. “We are very confident that it works,” but another trial J&J is conducting of its vaccine plus a booster shot “will give us a backup.”

The study released Wednesday also found that a second dose of J&J’s shot, administered two months later, led to a threefold increase in neutralizing antibodies. Stoffels said that’s positive news, as the drugmaker is still evaluating how long immunity from the single-shot will last, and whether higher antibody levels will be needed to combat new strains of the virus.

J&J kicked off the late-stage study of its two-dose vaccine regimen in November. Stoffels said the company is likely to finish enrolling the 30,000 participants before the end of first quarter, likely in March or April, and expects a data readout come summer.


The New Brunswick, New Jersey-based company’s vaccine candidate is made from a cold virus, called an adenovirus, that’s modified to make copies of the coronavirus’ spike protein, which the pathogen uses to enter cells.

Though the altered virus can’t replicate in humans, it induces an immune response that prepares the body for an actual COVID-19 infection. It was first developed with researchers at Harvard University who have spent years working on the adenovirus platform, which is also used in J&J’s Ebola vaccine, as well as its Zika, RSV, and HIV investigational vaccine candidates.

The NEJM report showed the vaccine was well-tolerated across all study participants. It also found that there was no difference in immunogencity between younger trial participants and the elderly, which is important given older populations are most vulnerable to the disease.

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