J&J says single dose of coronavirus vaccine 66% effective in large trial

A single shot of a coronavirus vaccine developed by Johnson & Johnson protected volunteers enrolled in a sprawling, multicountry study from developing COVID-19, results disclosed by the company Friday showed.

The finding is a boost to a sputtering global immunization drive, adding another effective vaccine to a mix of shots already cleared for use in dozens of nations. J&J, one of the world’s largest drugmakers, expects it can produce 1 billion doses of its vaccine this year.

But the results indicate vaccination was only 66% effective in preventing moderate or severe COVID-19 compared to a saline injection used as placebo. Expectations were for a higher number, particularly after shots developed by Pfizer and Moderna were found to be more than 90% effective at preventing symptomatic COVID-19.

In the U.S., efficacy was stronger, at 72%. But in Latin America and in South Africa, where new, more infectious variants are circulating, protection from the vaccine appeared less robust, at 66% and 57% effective, respectively.

The data come one day after Novavax reported results from two studies of its vaccine that also showed diminished efficacy against the coronavirus variant first detected in South Africa. Taken together, the two data sets signal the urgency behind vaccination drives now ongoing.

Even with lower efficacy, though, J&J’s vaccine could still play an important role, as Friday’s data show one dose can be protective. Pfizer’s and Moderna’s vaccines are given via two doses, as are most others now authorized or in late-stage testing.

J&J’s vaccine can also be shipped and stored at refrigerator temperatures, rather than the ultra-cold temperatures required for Pfizer’s and Moderna’s.

An independent committee overseeing J&J’s trial estimated the vaccine’s efficacy after 468 participants in the company’s trial got either moderate or severe COVID-19. Study investigators calculated efficacy against just severe disease as 85%, and J&J noted protection increased over time.

No vaccinated participant in the study required hospitalization or intensive care starting 28 days after receiving their shot.

J&J said it will soon ask the Food and Drug Administration to clear its vaccine for emergency use in the U.S. The agency would then begin the painstaking work of reviewing and corroborating J&J’s data, as well as convene an advisory committee to independently assess the results.

Prior meetings to review Pfizer’s and Moderna’s results were largely positive, despite some wrangling over authorization language. The more modest efficacy of J&J’s shot, by comparison, could present thornier questions for the committee to consider, as will the effect of new variants on protection.

The FDA authorized both Pfizer’s and Moderna’s shots about a month after announcement of initial data.

U.S. government officials have previously said they hoped J&J’s vaccine could win authorization in February, although Paul Stoffels, the company’s chief scientific officer, said in a mid-January interview with Bloomberg that an FDA decision may not come until March.

Through “Operation Warp Speed,” the U.S. pre-ordered 100 million doses of J&J’s vaccines at a price of $10 each. Per the August 2020 contract, 12 million doses are due to be delivered by the end of February — critical reinforcements for an immunization effort that’s already short on supply and struggling with other rollout hurdles.

But production may have already hit a snag. In mid-January, The New York Times reported J&J has fallen two months behind schedule, putting its supply schedule in jeopardy.

J&J has contracted with Somerset, New Jersey-based Catalent and Baltimore, Maryland-headquartered Emergent Biosolutions to manufacture the shot. It’s also producing doses at its own plant in Leiden, Netherlands.

J&J’s vaccine uses a different technology than Pfizer’s and Moderna’s. Genetic instructions for the coronavirus’ telltale spike protein are written into the genome of a harmless virus known as adenovirus type 26. Once injected, the re-engineered virus enters cells and instructs them to produce the spike protein, thereby teaching the body’s immune system to recognize and resist infection. (J&J uses the same technology for its Ebola vaccine, which was approved in Europe last year.)

An earlier study showed vaccination spurs an immune response tuned to the coronavirus’ spike that’s roughly equal to what occurs during an actual infection. Side effects were generally mild or moderate in nature, usually fatigue, headache, general soreness and injection site pain.

In announcing the larger trial results Friday, J&J said an independent committee monitoring the study did not report any significant safety concerns. Overall the rate of fever among participants was 9%, with only 0.2% experiencing fever classified as Grade 3.

No anaphylactic reactions — a new point of interest after reports following vaccination with Pfizer’s and Moderna’s shots — were observed in J&J’s study.

Testing had been briefly halted in October after a participant fell sick with an unexplained illness, but regulators allowed the company to resume soon thereafter. Even with the delay, enrollment into the Phase 3 trial, which involved 43,783 volunteers, was completed in less than four months, faster than any study in J&J’s history.

Nearly 14,000 participants were over 60 years old — an important group as older adults typically experience worse outcomes from COVID-19 compared to other ages. Protection was consistent in this group, J&J said.

Nearly three-fifths of volunteers in the trial overall are White, 19% are Black or African American, 9% are Native American and 3% are Asian. Almost half, 45%, are Hispanic or Latino.

In the U.S., where 19,302 participants were enrolled, the trial included more people who identify as White, about 74%.

While Pfizer, Moderna and other developers reached the testing finish line before J&J, the company’s development efforts still rank among the speediest ever in clinical research. J&J began initial vaccine work in late January, and in March linked up with the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center. There, a team led by Daniel Barouch had been working for years on a vaccine design using the adenovirus type 26.

Researchers at the center, like their peers at other laboratories across the world, quickly pivoted to studying SARS-CoV-2, the new coronavirus. Studies in mice and monkeys soon followed and, by the end of July, the first trial in humans.

Data from that study convinced J&J that a single dose could be protective, rather than the two-dose, “prime-boost” regimens favored by others. The company did hedge its bet, however, starting in November a large study of a two-dose regimen. With the weaker-than-expected efficacy, that trial now becomes more consequential as a second shot could potentially improve on protection.

More study results from other vaccine developers are expected soon. AstraZeneca, which last month won a conditional approval in the U.K. for its shot, could have data from a larger U.S. trial shortly, and CureVac is also awaiting important trial results.