Oxford coronavirus vaccine trial only has a 50% chance of success, professor leading project warns

Oxford coronavirus vaccine trial only has a 50% chance of success, professor leading project warns

  • Government struck a deal for 100 million doses of the jab ‘as early as possible’
  • Ministers hoped a third of them would be ready to roll out for use in September 
  • But Prof Adrian Hill said the rapidly disappearing virus is creating problems
  • If volunteers don’t catch it, scientists can’t prove the vaccine makes a difference
  • Here’s how to help people impacted by Covid-19

By Tom Pyman For Mailonline

Published: | Updated:

A much-anticipated coronavirus vaccine trial only has a 50 per cent chance of success – because the disease is disappearing so rapidly, the professor leading the project has warned.

Just days ago, pharmaceutical giant AstraZeneca announced it, had the capacity to make one billion doses of Oxford University’s promising jab, with Britain striking a deal for 100 million ‘as early as possible’.

That came after ministers said they hoped a third of those would be ready for September, at which point, if proven effective, people would be allowed to go back to work and businesses given the green light to reopen and start rebuilding the economy.

Professor Adrian Hill, pictured, said: ‘We’re in the bizarre position of wanting Covid to stay, at least for a little while’

However, Professor Adrian Hill told the Telegraph the rapid disappearance of the virus itself in the UK has thrown doubt on the team’s ability to meet the deadline in four months’ time.

If Covid-19 is not spreading in the community, volunteers will find it difficult to catch, meaning scientists can’t prove whether the vaccine actually makes any difference. 

Some 10,000 people are being recruited to test the jab over the coming weeks, but Prof Hill said he expected fewer than 50 of those to catch the virus, and the results could be deemed useless if fewer than 20 test positive. 

‘We said earlier in the year that there was an 80 per cent chance of developing an effective vaccine by September,’ he told the paper.

‘But at the moment, there’s a 50 per cent chance that we get no result at all.

‘We’re in the bizarre position of wanting Covid to stay, at least for a little while. But cases are declining.’

Oxford University’s jab was known as ChAdOx1 nCoV but has now been called AZD1222

AstraZeneca has signed a deal to mass-produce Oxford University’s promising COVID-19 jab and has agreements to supply 400million doses already

Business Secretary Alok Sharma said earlier this month the Government is ambitiously hoping to be in a position to roll-out a mass vaccination programme in the Autumn of this year.

But top scientists dealt a blow to the hopes of millions of Britons longing for an end to the pandemic when they warned a working vaccine is unlikely to be ready until 2021.

Doubts have been cast about the jab – one of the front-runners in the world’s vaccine race – after studies on monkeys suggested it didn’t stop them getting infected.

The Oxford/AstraZeneca jab, now called AZD1222, is currently in trials on humans to prove it is safe and the team say it is progressing well.

Meanwhile, stock markets were sent into a frenzy this week after promising results that showed another experimental vaccine, made by US firm Moderna, could block the virus in humans.

Prof Hill urged caution ahead of plans next month for the university to release results of a first trial conducted on more than 1,000 volunteers during the disease’s peak in April. 


Developing a vaccine is a complex procedure which relies on a number of lengthy steps.

But researchers racing to develop one for COVID-19 – which threatens to keep entire nations in lockdown until it can be stopped – are breaking through this stages at an unprecedented pace, scientists say.

One vaccine for rotavirus, a virus that causes deadly diarrhoea in children, took 26 years to make, the Washington Post reported, and one of its creators called this ‘pretty typical’.

Scientists must first sequence the virus they want to make a vaccine against – meaning they deconstruct it to examine its internal workings.

This process was sped up because the Chinese officials who discovered the coronavirus SARS-CoV-2 mapped the virus and shared it worldwide for free at the very start of the outbreak.

Scientists also noticed that it is almost identical to the one that causes SARS, a similar illness which hit Asia in 2002/3. This saved time because researchers already knew which areas of the virus they could target, and some had already tried to make SARS vaccines, which could work as a blueprint for tackling COVID-19.

Trials, which begin after a vaccine is painstakingly designed and produced in a laboratory, also take a long time. First, scientists must repeatedly test the vaccine on animals such as mice or monkeys. 

If it proves to be safe, this must then go on to very small human trials, then incrementally larger ones as the safety and effectiveness of it is constantly monitored.

Often, human trials take months or even years so scientists can be absolutely certain the vaccine won’t have any damaging side effects.

If there are any hiccups the researchers may have to tweak the chemical make-up of the vaccine and start again.

If things go smoothly, the vaccine can progress to the manufacturing phase and be produced en masse and sold to the people or governments who need them.

Scientists have claimed they could have a vaccine ready for COVID-19 by September this year, a break-neck pace which critics say is unlikely.

Professor Robin Shattock, an immunity expert at Imperial College London, said: ‘It’s highly unlikely that a vaccine will be available for use by September. 

‘It will be critical to build the evidence base to show a vaccine works before it’s deployed. This takes time and is dependent on seeing a difference in the number of infections between active vaccine and a placebo. 

‘The lower the transmission rate in the UK, the longer it will take to generate such data.’  


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