Johnson & Johnson COVID-19 Vaccine Trial Results Underscore Drug's Big Advantage

The first results of Johnson & Johnson's COVID-19 vaccine candidate are in, and while the efficacy numbers for the Phase 3 trial may not be the best out there, the shot does have one huge advantage over rival drugs from Pfizer, Moderna, and others. The so-called Janssen COVID-19 vaccine candidate proved to be 85-percent effective overall in preventing severe cases of coronavirus, but arguably equally important is the fact that it's a single shot vaccine, unlike most of the others currently being deployed.

Vaccine candidates from Pfizer, Moderna, and others require two shots for maximum effectiveness to be reached. The time between those doses being administered varies, but is usually 3-4 weeks in length.

It presents a significant logistics problem, especially given that – in the US for example – emergency authorization for use is based on that clinically-tested period being observed. It means healthcare providers must not only schedule those who have received their first dose of the vaccine for a second appointment, but make sure that the supply chain and other logistics for that second dose are managed correctly. It's proved to be a not-insignificant hurdle, with shortages of the drugs in some cases leading to delayed or missed second shots.

The Johnson & Johnson candidate, in contrast, requires just one shot. It can be shipped using the same cold chain system as existing vaccines – it's estimated to remain stable for two years at -4 degrees Fahrenheit, and can last for three months at temperatures between 36-46 degrees Fahrenheit – and the pharma company says it expects to sell it on a not-for-profit basis for emergency pandemic use.

The Phase 3 ENSEMBLE study is a randomized, double-blind, placebo-controlled clinical trial for adults 18 years or older. It consisted of over 19,300 participants in the US, almost 18,000 in Central and South America, and around 6,500 in South Africa, with a 45/55 female to male split, and broad ethnicity demographics.

"The vaccine candidate was 85 percent effective in preventing severe disease across all regions studied," Johnson & Johnson says, "28 days after vaccination in all adults 18 years and older. Efficacy against severe disease increased over time with no cases in vaccinated participants reported after day 49."

No cases of COVID-19 requiring hospitalization and things like mechanical ventilation were reported among those vaccinated, 28 days post-shot. Of the total 43,783 cohort in the study, 468 were observed with symptomatic cases of COVID-19.

The trial also saw infections with the SARS-CoV-2 Variant B.1.351 Lineage observed in South Africa.

"Among all participants from different geographies and including those infected with an emerging viral variant, Janssen's COVID-19 vaccine candidate was 66% effective overall in preventing moderate to severe COVID-19, 28 days after vaccination," the company reports. "The onset of protection was observed as early as day 14. The level of protection against moderate to severe COVID-19 infection was 72% in the United States, 66% in Latin America and 57% in South Africa, 28 days post-vaccination."

Johnson & Johnson says it plans to submit the Janssen COVID-19 vaccine candidate for emergency use authorization from the US FDA in February. Assuming that's granted, it is prepared to ship the drug immediately.