J&J single shot sees 66% efficacy in moderate COVID-19, 85% in severe cases; shares fall

COVID-19 vaccine
(Kunal Mahto/iStock/Getty Images Plus/Getty Images)

Johnson & Johnson saw its shares fall 4% in early trading on the news that its one-shot COVID-19 vaccine saw 66% efficacy in moderate to severe disease, rising to 85% in severe disease.

That 66% headline hit J&J’s shares hard, but the data (published via a press release, so caveats abound until peer reviewed in a  journal) are better than they appear at first glance.

Breaking it down, the phase 3 trial of J&J’s one-and-done COVID-19 vaccine showed it was 72% effective in the U.S. in preventing severe to moderate COVID-19, but this fell to the 66% headline figure as its overall effectiveness was worse outside the U.S.: 66% in Latin America and 57% in South Africa, all coming 28 days post-vaccination.

The better news is that it was 85% effective overall in preventing severe disease and showed “(c)omplete protection against COVID-19 related hospitalization and death” after 28 days.

The data are based on 43,783 participants accruing 468 symptomatic cases of COVID-19, and the study found that protection was “generally consistent” across race and age groups, including adults over 60 years of age. (There were 13,610 in this bracket, important as this is the group at highest risk for severe disease and death.)

And the U.S. Big Pharma found efficacy against severe disease “increased over time,” with no cases in vaccinated participants reported after Day 49. It said in a call Friday morning that it now plots to file for an emergency usage authorization next week.

“There was a clear effect of the vaccine on COVID-19 cases requiring medical intervention (hospitalization, ICU admission, mechanical ventilation, extracorporeal membrane oxygenation (ECMO)), with no reported cases among participants who had received the Janssen COVID-19 vaccine, 28 days post-vaccination,” it said.

Safety data also looked clean, with overall fever rates at 9% and grade 3 fever at just 0.2%. Overall serious safety worries reported were higher in the placebo group as compared to the active vaccine candidate, with no anaphylaxis reported.

But while there is good news here, it has high numbers to beat out: Moderna, Pfizer-BioNTech and today Novavax have all seen around a 95% efficacy rate in the original SARS-CoV-02 variant and still shown up strong numbers in the so-called British variant, though the variant first seen from South Africa appears to be dragging that efficacy down to about 50%.

It appears on par with AstraZeneca and Oxford University's vaccine effort, which hit similar efficacy numbers. Analysts still see AZ and now J&J second in the vaccine race, with new technologies from Pfizer, Moderna and Novavax all leading the way (and all seeing their shares jump on the news).

But J&J only requires one shot to get these results, unlike the two needed for all its current rivals; it also appears to have fewer concerns over anaphylaxis seen with mRNA vaccines, and, with so many governments scrambling for limited doses and only giving one out of the two shots to most of the population in an effort to preserve precious supplies and maximize partial protection, a J&J shot will still prove an attractive option.

“These results are a testament to the extraordinary efforts of everyone involved in our COVID-19 vaccine candidate clinical program, and we are extremely grateful to the clinical trial staff and trial participants for their invaluable contributions,” said Mathai Mammen, M.D., Ph.D., global head of Janssen R&D.  

“Changing the trajectory of the pandemic will require mass vaccination to create herd immunity, and a single-dose regimen with fast onset of protection and ease of delivery and storage provides a potential solution to reaching as many people as possible. The ability to avoid hospitalizations and deaths would change the game in combating the pandemic.”

The future will be hitting the new and scarier variants that have been identified in the U.K., Brazil and South Africa. The so-called British variant appears to be more transmissible, but it’s still up for debate whether it is more deadly. It, however, to appears to be susceptible to vaccination. The South African variant is, however, something of a vaccine-buster, with data out from Novavax today showing its vaccine efficacy dropped from around 96% in the old variant to 49% when pitted in a trial against the strain from South Africa.

Future vaccination strategies will need to up their efficacy against these new and emerging strains.

J&J said its phase 3 study results “include efficacy against newly emerging strains of coronavirus, including some highly infectious variants present in the US, Latin America and South Africa,” although it has not released a breakdown of the data across variants.

It did say protection remained consistent “across all variants and regions studied, including South Africa where nearly all cases of COVID-19 (95%) were due to infection with a SARS-CoV-2 variant from the B.1.351 lineage.”

It continues to study a two-dose program in an ongoing phase 2.