Johnson & Johnson says its single-shot vaccine is 66 percent effective in preventing moderate to severe COVID-19, 28 days after vaccination. The company reported its interim analysis of phase 3 trial data on 43,783 participants accruing 468 symptomatic COVID-19 cases.
The efficacy of the vaccine varied from region to region. The vaccine was reported to be 72 percent effective in the US, 66 percent in Latin America and a weaker response of 57 percent efficacy was seen in South Africa, where a worrisome variant is the predominant strain of the virus.
The phase 3 trial results found that Janssen's vaccine was 85 percent effective overall at preventing severe disease, which includes illnesses requiring hospitalisation and death. It highlighted that the efficacy increased after day 49 with no severe cases found in the vaccinated group.
Paul Stoffels, Vice Chairman of the Executive Committee and Chief Scientific Officer, Johnson & Johnson in a statement said, "The potential to significantly reduce the burden of severe disease, by providing an effective and well-tolerated vaccine with just one immunization, is a critical component of the global public health response."
No major side effects from the vaccine were reported, including severe allergic reactions, such as anaphylaxis. J&J's vaccine is of interest for India as well, as domestic vaccine maker Biological E has entered into an agreement with the pharma major to manufacture the drug substance and finished product of the vaccine.
The efficacy results for Belgium-based Janssen's vaccine are much lower than the already approved vaccines, however it crosses the efficacy threshold of 50 percent put by the US and WHO vaccine regulatory guidelines. The single shot vaccine may be more feasible logistically to roll out versus all the others needing two shots. This especially at a time when vaccine supplies are already dwindling.
The mRNA vaccines of Pfizer-Bio-NTech and Moderna have both shown above 95 percent efficacy and Oxford-Astrazeneca has reported above 70 percent efficacy. All three are two-dose vaccines.
Another vaccine maker Novavax released its first interim analysis of its COVID-19 vaccine on January 29, which showed 89 percent efficacy in Phase 3 trials in UK. Analysis of 62 confirmed COVID-19 cases efficacy by strain was calculated to be 95.6 percent against the original COVID-19 strain and 85.6 percent against the UK variant strain. Novavax vaccine also showed lower efficacy against South African strain in phase 2 trials.
J&J in a statement said that Janssen's single-dose vaccine is compatible with standard vaccine distribution channels. J&J's vaccine is estimated to remain stable for 3 months at regular refrigeration temperatures 2-8°C and for two years at -20°C.
Mathai Mammen, Global Head, Janssen Research & Development in a statement said, "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."
J&J intends to file for US emergency use authorisation in early February and expects to meet its 2021 supply commitments with the manufacturing timelines.
In India, J&J had earlier indicated that its tie-up with Biological E will allow for production of 400-500 million doses per year.
