Courtesy The Times (UK)

Oxford University scientists said that they had created a vaccine for the world” as trial results showed that their jab worked well enough to apply immediately for regulatory approval.

The vaccine involves two injections, administered about a month apart. The results suggest that using a lower first dose — which was done by accident — could increase efficacy to 90 per cent. That finding relied, however, on limited data and may be amended.

Overall, a trial involving 24,000 people suggested that the vaccine was about 70 per cent effective. It prevented severe disease and there are promising early signs that it might also block transmission of the virus. No dangerous side-effects were reported and the medical regulator has begun to review safety and efficacy data.

Britain has ordered 100 million doses. Astrazeneca, the drug company that is working with the university, said yesterday that four million of those would be ready to be sent to care homes, GP clinics and other vaccination centres by the end of the year.

I think we have a highly effective, safe vaccine,” Sir Mene Pangalos, the head of research and development at Astrazeneca, which is based in Cambridge, said. Our job now is as rapidly as possible to work with regulators around the world.”

Three of the six vaccines of which Britain has secured supplies — from Oxford, Pfizer and Moderna — have now produced encouraging final-stage results. Altogether, they could supply 145 million doses, enough to immunise the entire country.

The Oxford vaccine can be stored in a normal fridge, unlike Pfizer’s, which must be kept at minus 70C. It is also considerably cheaper, costing a few pounds per dose.

The first doses could be administered before Christmas.

Boris Johnson hailed the announcement as incredibly exciting”. Matt Hancock, the health secretary, said that it could facilitate a return to normal life by Easter. I’m booking my tickets to Wimbledon,” one official said.

The Duke of Cambridge said he had called the Oxford researchers to congratulate them. He told them: I’m so thrilled that you’ve cracked it.”

Andrew Pollard, director of the Oxford Vaccine Group, said: We have a vaccine for the world . . . this is an incredibly exciting moment for human health. We’ve got a vaccine which is highly effective. It prevents severe disease and hospitalisation . . . because the vaccine can be stored at fridge temperatures, it can be distributed using the normal immunisation distribution system.”

Professor Pollard said that it was already being manufactured at ten sites around the world.

The headline result of 70 per cent effectiveness is less impressive than Pfizer’s results, released this month, of more than 90 per cent. However, the Oxford vaccine also achieved a 90 per cent success rate because of a lucky break. A dosing error during trials in the spring meant that volunteers were initially given half the amount of the vaccine that 500 participants of earlier trials had received.

When the volunteers experienced much milder side-effects than expected, researchers discovered their mistake and gave a booster full dose. Those who enrolled later received the full amount from the start. Trial results found that the correct” dosage had a 62 per cent efficacy rate, but the accidental” level was 90 per cent effective. The 70 per cent figure comes from combining the sub-group results.

Sarah Gilbert, a professor of vaccinology at Oxford and one of the team leaders, said that a lower initial dose might better resemble a natural infection. She added: What we’ve always tried to do with the vaccine is fool the immune system into thinking that there’s a dangerous infection there that it needs to respond to, but in a very safe way — so we get the immune response and we get the immune memory, and that’s there, waiting and ready if the pathogen itself is then encountered.

It could be that by giving a small amount of the vaccine to start with and following up with a big amount, that’s a better way of kicking the immune system into action.”

The overall findings are based on trials carried out in Britain and Brazil involving 24,000 people. About a quarter were older than 55 but the data does not yet show how effective the jab is at protecting high-risk groups. It is also uncertain how long protection will last.

Professor Pollard said using a lower first dose could mean that stockpiles of the vaccine would stretch further.

Researchers said there were also lower rates of asymptomatic infection in the vaccinated groups. This would make it the first trial to answer the key question of whether the vaccine stops transmission as well as illness.

The Oxford vaccine works on a different principle from Pfizer’s. It uses a harmless chimpanzee virus to ferry a portion of the coronavirus genetic code into people’s cells. This makes the cells churn out fragments of the surface of the coronavirus, training the immune system to fend off the real pathogen.Coronavirus