A one-dose COVID-19 vaccine developed by Johnson & Johnson’s pharma division Janssen has demonstrated an overall efficacy of 66% in a phase 3 trial.
The phase 3 ENSEMBLE trial evaluated the efficacy and safety of the vaccine for protection against moderate-to-severe COVID-19.
The study was conducted in eight countries across three continents, with 44% of participants enrolled in the US, 41% in Central and South America and 15% in South Africa.
Across all participants from the different geographies, the vaccine was 66% effective overall in preventing moderate-to-severe COVID-19, 28 days after vaccination.
In the US, the efficacy rate was 72% while in Latin America and South Africa the vaccine was 66% and 57% effective, respectively.
In South Africa, J&J said that 95% of the COVID-19 cases observed in the study were caused by the newly discovered B.1.351 virus variant.
Although the vaccine is less effective against the B.1.351 variant that was first discovered in South Africa, J&J said that the jab was 85% effective in preventing severe disease across all regions studied.
Importantly, the one-dose shot could be rolled out with more ease and efficiency compared to other two-dose regimens.
“A one-shot vaccine is considered by the World Health Organization to be the best option in pandemic settings, enhancing access, distribution and compliance,” said Paul Stoffels, vice chairman of the executive committee and chief scientific officer of J&J.
“[An efficacy rate of] 85% in preventing severe COVID-19 disease and prevention of COVID-19-related medical interventions will potentially protect hundreds of millions of people from serious and fatal outcomes of COVID-19,” he added.
J&J’s vaccine is estimated to remain stable for two years at -20°C and for at least three months at +2-+8°C (standard refrigerator temperatures).
In a statement, the pharma giant added that it is planning to file for a US Emergency Use Authorisation (EUA) early next month.
Following authorisation, J&J will ‘immediately’ be able to start shipping doses of the COVID-19 vaccine.
J&J reached an agreement with the US government in August 2020 to supply 100 million doses of its COVID-19 vaccine.
Under the terms of the deal, the US Biomedical Advanced Research and Development Authority (BARDA) and the US Department of Defense are committing $1bn for the first 100 million doses.
The US government also has the option to purchase an additional 200 million doses under a subsequent agreement.
The European Commission also has an advanced purchase agreement with J&J for 200 million doses of the vaccine, which includes an option to secure up to 200 million additional doses after the initial supply.
In the UK, the government has also secured 30 million doses of J&J’s vaccine, which will be supplied on a not-for-profit basis during the emergency pandemic.