Johnson & Johnson's COVID-19 vaccine is 85% effective against severe cases, and 66% effective overall per trial data

Darrell Etherington
·2-min read
SPAIN - 2021/01/27: In this photo illustration a medical syringe seen displayed in front of the Johnson & Johnson logo. (Photo Illustration by Thiago Prud锚ncio/SOPA Images/LightRocket via Getty Images)

Another COVID-19 vaccine is almost ready to begin being distributed -- a single-shot inoculation made by Johnson & Johnson's Janssen Pharmaceuticals subsidiary. The company just released an efficacy report based on data from its Phase 3 trial, which found that the new vaccine is 66% effective overall in preventing moderate to severe incarnations of COVID-19 in those who received the jab, and 85% effective in preventing severe disease.

Those numbers aren't as impressive as the reported figures for the Moderna and Pfizer/BioNTech vaccines that are already being distributed via emergency FDA approval, both of which reported 90+% efficacy. But Johnson & Johnson's vaccine is a single shot rather than a two-course treatment, which should make it much easier to distribute much more quickly. The vaccine also showed 100% efficacy in preventing hospitalization or death among participants in the trial, 28 days after vaccination, which is a key measure when considering the broader impact of COVID-19 on healthcare resources. Efficacy varied by region, with the jab proving 72% effective in the U.S. across moderate and severe cases versus 66% globally.

It's also important to note that Johnson & Johnson's Phase 3 trial is happening amid the emergence of new strains of the virus, including much more contagious versions like the U.K. and South African variants. At the time that both Moderna and BioNTech released their trial data, these variants hadn't yet emerged or been confirmed by pandemic researchers.

Johnson & Johnson's vaccine uses a modified version of a common cold virus to deliver DNA that provides a person's body with instructions on building a replica of the spike protein that SARS-CoV-2 uses to attach to cells. The modified adenovirus can't replicate in human cells, however, meaning it won't lead to illness -- only an immune response that can later be employed to combat contracting the virus that leads to COVID-19. This adenovirus method is much more proven in terms of use in human patients versus the mRNA method that the other vaccines currently in use employ.

All of which is to say, despite headline numbers that appear to fall short relative to the data we've seen from Moderna and Pfizer, this Johnson & Johnson report is actually very encouraging. The company says it expects to file a request for an Emergency Use Approval (EUA) from the FDA in February, which could see it begin to be distributed next month, adding yet another weapon in the arsenal to combat the global pandemic.