Johnson & Johnson single-dose vaccine is effective against Covid-19

Vaccine is 66 per cent effective overall, but less so against South African variant

Johnson & Johnson’s long-awaited single-shot vaccine appears to protect against Covid-19 with only one shot, the company announced.

J&J said that in the US and seven other countries, the single-shot vaccine was 66 per cent effective overall at preventing moderate to severe illness, and much more protective – 85 per cent – against the most serious symptoms.

That means it is not as strong as some two-shot rivals but still potentially helpful for a world in dire need of more doses.

US infectious disease specialist Anthony Fauci said the variations in effectiveness around the world underlined the need to vaccinate as many people as quickly as possible to prevent new variants from emerging.

“It’s really a wake-up call for us to be nimble and to be able to adjust, as this virus will continue for certain to evolve,” Dr Fauci said.

A high bar has been set by two authorised vaccines from Pfizer-BioNTech and Moderna, each of which was about 95 per cent effective in preventing symptomatic illness in pivotal trials when given in two doses.

Those trials, however, were conducted mainly in the US and before new variants emerged.

A single-dose vaccine would offer governments a simpler route to proving protection for more people. It costs about $10 per dose, so would be beneficial for poorer countries, and can be stored at regular fridge temperatures so distribution and handling is easier.

“We’re proud to have reached this critical milestone and our commitment to address this global health crisis continues with urgency for everyone, everywhere,” the company’s chief executive, Alex Gorsky, said.

The company is quickly expected to apply for a US emergency authorisation, and could therefore soon be the third vaccine available in the world's hardest-hit country.

“These top-line results with a single-shot Covid-19 vaccine candidate represent a promising moment, said J&J’s chief scientific officer, Paul Stoffels.

“The potential to significantly reduce the burden of severe disease, by providing an effective and well-tolerated vaccine with just one immunisation, is a critical component of the global public health response.

“A one-shot vaccine is considered by the World Health Organisation to be the best option in pandemic settings, enhancing access, distribution and compliance.”

The vaccine is made by the US company’s subsidiary Janssen, based in the Netherlands, and was trialled in Britain. The UK government has bought 30 million doses, while the EU has ordered 400 million doses.

There was some geographic variation in the J&J findings. The vaccine worked better in the US – 72 per cent effective against moderate to severe Covid – compared with 57 per cent in South Africa, where it was up against a more contagious variant of the virus.

“Gambling on one dose was certainly worthwhile,” said Dr Mathai Mammen, global research chief for J&J’s Janssen Pharmaceutical unit.

With vaccinations off to a rocky start globally, experts had been counting on a one-dose vaccine that would stretch scarce supplies and avoid the logistical difficulties of getting people to return for boosters.

But with some other competing vaccines shown to be 95 per cent effective after two doses, at question is whether somewhat less protection is an acceptable trade-off to get more shots in arms quickly.

The company said within a week it would file an application for emergency use in the US, and then abroad. It expects to supply 100 million doses to the US by June, and expects to have some ready to ship as soon as authorities give the green light.

These are preliminary findings from a study of 44,000 volunteers that is not yet complete. Researchers tracked illnesses starting 28 days after vaccination – about the time when, if participants were getting a two-dose variety instead, they would have needed another shot.

After day 28, no one who was vaccinated needed to go to hospital or died, regardless of whether they were exposed to “regular Covid or these particularly nasty variants”, Mr Mammen said. When the immunised were infected, their illness was milder.

The announcement came shortly after success was announced for another vaccine.

The Novavax vaccine trials showed it offers 89 per cent protection against coronavirus.

The product is due to be manufactured in Britain and appears to be effective against the original strain of coronavirus and a mutant strain first identified in Kent, south-east England.

The Novavax drug showed about 60 per cent effectiveness against the strain of Covid-19 first identified in South Africa, which has been problematic for scientists owing to concerns it may evade vaccines.

The UK secured access to 60 million Novavax doses, which will be available in the second half of this year if the vaccine is approved by the medicines regulator.

More than 15,000 people in the UK took part in the clinical trial, of whom 27 per cent were aged 65 or older. The study assessed how effective the vaccine was when transmission of Covid-19 was high in the UK, and with the variant strain first identified in England circulating widely.

Prof Paul Heath, Novavax’s clinical trial chief investigator, said the data showed science was able to respond to mutations.

Kate Bingham, the former head of the UK’s vaccine task force and the person who placed the orders for Novavax doses, said she was delighted but the next goal was to find an easier way to administer vaccines.

“Frankly, two injections delivered by healthcare professionals is not a good way of delivering vaccines,” she said. “We need to get vaccine formats that are much more scalable and distributable. So whether they’re pills or patches or nose sprays, we need to find better ways of delivering vaccines.”

Defeating the scourge, which has killed more than two million people worldwide, will require vaccinating billions, and the shots being rolled out in different countries so far all require two doses a few weeks apart for full protection. Early data is mixed on exactly how well all the different kinds work, but shots made by Pfizer-BioNTech and Moderna appear to be about 95 per cent protective after the second dose.

But amid shortages, some countries have advised delaying the second dose of certain vaccines with little data on how that would affect protection.

All Covid-19 vaccines train the body to recognise the new coronavirus, usually by spotting the spiky protein that coats it. But they are made in very different ways.

J&J’s shot uses a cold virus like a Trojan horse to carry the spike gene into the body, where cells make harmless copies of the protein to prime the immune system in case the real virus comes along.

Rival AstraZeneca makes a similar cold virus vaccine that requires two doses. Both the AstraZeneca and J&J vaccines can be stored in a refrigerator, making them easier to ship and to use in developing countries than the frozen kind made by Pfizer-BioNTech and Moderna.

It is not clear exactly how well the AstraZeneca version, being used in Britain and several other countries, works. Tests in Britain, South Africa and Brazil suggested two doses are about 70 per cent effective, although there are questions about how much protection older adults receive. An ongoing US study may provide more information.

J&J said its vaccine works consistently in a broad range of people. A third of participants were aged over 60, and more than 40 per cent had other conditions that put them at risk of severe Covid-19, such as obesity, diabetes and Aids.

J&J said the vaccine is safe, with reactions similar to other Covid-19 shots such as fever that occur when the immune system is revved up.

While it released few details, the company said there were no serious allergic reactions. But occasionally other Covid-19 vaccines trigger such reactions, which can be reversed if promptly treated – and authorities have warned people to be on the lookout, regardless of which type of vaccine is used.

J&J had hedged its bets with a study of a two-dose version of its vaccine, which is still under way.