The trial results of Johnson & Johnson’s Covid-19 vaccine are “extremely encouraging” and suggest that a single dose can be effective, experts have said.
The single-shot vaccine – developed by Johnson & Johnson’s pharmaceutical arm Janssen – is 66% effective overall at preventing moderate to severe coronavirus 28 days after vaccination, results show.
Some 30 million doses of the vaccine have been ordered by the UK, with deliveries expected in the second half of this year if the jab is approved by regulators.
Professor Kevin Marsh, co-lead of the Covid 19 team at the African Academy of Sciences, and Professor of Tropical Medicine at the University of Oxford, said the results were “extremely encouraging”.
He said: “It is possible that some people will look at the overall reported efficacy of 66% in preventing moderate to severe Covid-19 and focus on comparisons with potentially higher ‘top line’ efficacy reported for some other vaccines.
“This would be a mistake. The real headline result is that a single-shot vaccine, capable of easy long-term storage and administration, provided complete protection against hospitalisation and death.”
The new vaccine was tested in a clinical trial involving 43,783 people, during which time 468 Covid-19 cases were recorded.
Johnson & Johnson plans to file for regulatory approval in the US next week, followed shortly by applying for approval in Europe and the UK.
Dr Alexander Edwards, associate professor in biomedical technology at the Reading School of Pharmacy, University of Reading, said the “exciting” element of the vaccine’s trial was that it assessed a single dose, rather than two.
He said: “There has been great debate about one vs two doses and timing of doses for the first few vaccines to be rolled out.
“Hopefully, whilst this is a different product, this trial starts to provide evidence that single-dose vaccination can be protective. ”
Dr Edwards said the results did not mean that a second dose was not needed for other vaccines, adding: “People must still make every effort to complete a full course of two doses for those vaccines.”
Janssen is continuing trials into two doses of its vaccine to see whether this produces an even higher efficacy.
Dr Sheuli Porkess, chair of the policy and communications group at the Faculty of Pharmaceutical Medicine, said: “We look forward to seeing the outcome of regulatory review of the J&J vaccine, with many others still in development.
“As with all vaccines that are approved by the Medicines and Healthcare products Regulatory Agency, this vaccine would need to demonstrate rigorous safety and quality standards enabling widespread use.
“Effectiveness and safety monitoring would be continued following use of the vaccine in practice.”