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Oxford academic dismisses idea of deliberately infecting volunteers with Covid-19 to test vaccine

Professor Sarah Gilbert said it would not be safe for them to do a so-called 'challenge trial' of Oxford University's Covid-19 vaccine candidate

Professor Sarah Gilbert said it would not be safe for them to do a so-called ‘challenge trial’ of Oxford University’s Covid-19 vaccine candidate 

An Oxford academic today dismissed the idea of deliberately infecting volunteers with Covid-19 to test the university’s experimental vaccine because no treatment currently exists to keep patients safe.

Hopes of ending the Covid-19 pandemic with a vaccine grew yesterday after data revealed Oxford’s jab was safe and provokes an immune reaction that lasts for at least two months.

It led the team to say it was ‘possible’ that the vaccine could be ready by December — but there are fears the roll-out of the jab will be held up due to a lack of data. 

The virus is not circulating as much as it was at the start of the trial, meaning volunteers may not naturally be exposed to the coronavirus, which has prompted calls for so-called ‘challenge trials’. 

But Professor Sarah Gilbert, who is leading the Oxford team, said it would not be safe for them to carry out a ‘challenge trial’ because there is no effective drug to save those who get severely sick.

While scientists globally are racing to find a cure for Covid-19, no drugs have been proven to stop the disease progressing once someone is infected. Two medicines — remdesivir and dexamethasone — have only been shown to reduce the risk of death in patients already hospitalised. 

But Professor Gilbert is still confident the jab, being mass-manufactured by pharma giant AstraZeneca, could be ready for the most vulnerable people by the end of the year.

The Oxford team initially hoped it would be ready by September when they began trials in April. Ministers have already bought 100million doses and hoped they could start vaccinating in the autumn. 

However, there are a number of hurdles to get through first, including proving the vaccine actually works. The results from the first phase, revealed yesterday in The Lancet, only show it has promise. 

But Professor Gilbert still has confidence the jab could be ready for the most vulnerable people by Christmas. Pictured: Elisa Granato being given the vaccine in April

But Professor Gilbert still has confidence the jab could be ready for the most vulnerable people by Christmas. Pictured: Elisa Granato being given the vaccine in April

But Professor Gilbert still has confidence the jab could be ready for the most vulnerable people by Christmas. Pictured: Elisa Granato being given the vaccine in April

The Oxford team had initially hoped it would be ready by September when they began trials in April (pictured)

The Oxford team had initially hoped it would be ready by September when they began trials in April (pictured)

The Oxford team had initially hoped it would be ready by September when they began trials in April (pictured)

Speaking on BBC Radio 4’s Today programme, Professor Gilbert said a challenge trial is not something that will be conducted by Oxford in the foreseeable future.

Challenge trials are commonly deployed by scientists trying to develop a vaccine and have been used in malaria, typhoid and flu.

But, unlike those illnesses, there is little to stop the participants falling seriously ill with the coronavirus.  

Professor Gilbert said: ‘It is something that’s done for a number of different vaccine development programmes for other respiratory viruses such as flu. 

‘But in order for it to happen you have to have a number of things in place and one of those is having an effective therapy for people who you deliberately infect as part of the challenge trial who maybe don’t clear the infection and at the moment we don’t have that effective therapy.

BRITAIN SIGNS DEALS WITH TWO PHARMA FIRMS FOR 90MILLION DOSES OF DIFFERENT COVID-19 VACCINES 

Britain has signed deals with two foreign pharmaceutical giants for 90million doses of different experimental coronavirus vaccines. 

Agreement has been reached for 30million doses from German firm BioNTech and the US company Pfizer, and 60million doses from France’s Valneva.

The figure is in addition to the 100million doses of vaccine that are being developed by Oxford University in partnership with AstraZeneca, as well as another at Imperial College London which started human trials in June.

Business Secretary Alok Sharma said the new agreements would ‘ensure the UK has the best chance possible of securing a vaccine that protects those most at risk’.

It is not clear exactly how much the Department of Health has paid for individual vaccines, but it announced in May a £131m fund to develop vaccine-making facilities.

And it has given Valneva – the French company supplying 90m vaccines – an undisclosed amount of money to expand its factory in Livingston, Scotland. 

But campaigners have been critical of the UK using its buying power to swoop over the heads of poorer countries and snap up promising jabs.

Heidi Chow from Global Justice Now said: ‘This UK-first approach exposes the government’s rhetoric on equitable global access to COVID-19 vaccines as mere lip-service. 

‘Buying up advanced supplies of unproven vaccines encourages other rich countries to do the same which will ultimately leave poorer countries without. The only way to beat this pandemic is through collaboration rather than competition.’

Roz Scourse, from Medecins Sans Frontieres, added: ‘This deal is the UK’s latest attempt to get first access to COVID-19 vaccines. 

‘Access to a successful vaccine should not be determined on who can pay the most, but on health needs and should prioritise health care workers and vulnerable populations worldwide. 

‘Despite what the UK has been saying about the need to ensure equitable access to COVID-19 vaccines globally, what these secretive deals will actually do is use up initial supplies of vaccines, undermining allocation according to need.’

‘We will need everything to be done safely before we can start to do challenge trials and ethics would require having an effective treatment.’

Scores of experts have called for controversial challenge trials during the pandemic as a way of speeding up the hunt for a vaccine. 

A group of 100 leading scientists recently wrote an open letter to the US National Institutes of Health saying the benefits of bringing a vaccine to the masses outweighs the risk to trialists’ health.

The group called for healthy people to be purposely infected because it could rapidly accelerate studies on experimental jabs which are struggling to recruit volunteers.

With falling Covid-19 infection rates in some parts of the world, including Europe, there are concerns trial results will take too long to come out. 

Professor Gilbert has previously said low transmission rates in the UK mean there is ‘little chance’ of trials in the country proving the vaccine is efficient.

It has led Oxford to take their vaccine trial to South Africa and Brazil, two countries where cases of Covid-19 are accelerating. 

However, Professor Gilbert said: ‘The end of the year target for getting vaccine rollout is a possibility but there’s absolutely no certainty because we need three things.’

Those three things are the results from phase three trials, the ability for manufacturers to produce large quantities of the virus, and regulators to approve the vaccine. 

‘The regulators have to agree under emergency-use licensure. The regulators are in control of how long that decision will take,’ Professor Gilbert said.

‘Those three things have to happen before we see large numbers of people being vaccinated.’ 

Data from Oxford University’s phase one trial were published yesterday after huge anticipation, and showed the jab is safe and provokes an immune reaction that lasts for at least two months.

The Covid-19 vaccine, named AZD1222, had been given to 543 people out of a group of 1,077.

The other half were given a meningitis jab so their reactions could be compared and scientists could be sure the effects of the coronavirus jab weren’t random.

Researchers wanted to find out whether the vaccine boosted either of two types of immunity — antibodies, which are disease-fighting substances; and T-cell immunity, with T cells able to produce antibodies and also to attack viruses themselves.

The vaccine produced ‘strong’ responses on both accounts, the study found. More than 91 per cent of volunteers injected produced an immune response against the coronavirus that lasted a month or more.

Immune responses remained strong for at least 56 days, according to results in The Lancet. But it won’t be licensed for human use yet because it has not been proven to work. 

If the vaccine is given to the public it is likely to be in two doses given close together, developers said, because that seems to strengthen the body’s response. 

Professor Gilbert admitted today that although Oxford University’s vaccine — called AZD1222 — has shown promise, there is a need to find ‘long-term answers’.

Scientists haven’t quantified the level of immune response that a vaccine will need to provoke in order for it to actually protect against Covid-19. 

Professor Gilbert said: ‘As more vaccines go into phase three trials and we start to see how effective different vaccines are, we’ll have a lot more information about the level of antibody and T-cell responses that are needed to protect people, and we need to see some vaccines that don’t work particularly well in order to really understand what level of immunity to get to for a vaccine that does work well .’   

Crucially, nobody suffered any bad side effects from the vaccine and it is stimulating the immune system as scientists hoped.

Some people developed headaches, tiredness and pain in their arm after they were given the jab, but scientists claimed none of the side effects were severe. 

Professor Adrian Hill, director of the Jenner Institute at Oxford, said: ‘It’s possible there’ll be a vaccine being used by the end of the year.

‘What that needs is enough cases in the probably about 50,000 people who will be in trials by six weeks’ time, including the very large US trial, and to have an adequate incidence.

‘But of course the vaccine has to work. Even if it worked by early November, it might be a little before that, you might have emergency use authorisation in a month and then you would be deploying in December.

‘So it’s possible but we certainly can’t guarantee it – that depends on incidence of the disease, as I said earlier.’

However Prime Minister Boris Johnson yesterday tried to temper expectations when he admitted he wasn’t totally confident there would even be a vaccine by the end of next year.

Speaking on Sky News, Mr Johnson said: ‘I wish I could say that I was 100 per cent confident we’ll get a vaccine for Covid-19.

‘Obviously I’m hopeful — I’ve got my fingers crossed — but to say I’m 100 per cent confident that we’ll get a vaccine this year, or indeed next year is, alas, just an exaggeration — we’re not there yet.

‘If you talk to the scientists they think the sheer weight of international effort is going to produce something. They’re pretty confident that we’ll get some sort of treatments some sort of vaccines that will really make a difference.

‘But can I tell you that I’m 100 per cent confident? No.

‘That’s why we’ve got to continue with our current approach – maintaining the social distancing measures… we’ve got to continue to do all the sensible things; washing our hands. All those basic things.’

Mr Johnson added: ‘It may be that the vaccine is going to come riding over the hill like the cavalry but we just can’t count on it right now.’

Oxford University’s vaccine is already being manufactured by pharmaceutical giant AstraZeneca and the UK Government has ordered 100million doses ahead of time.   

A deal has been secured for a further 90million doses of two types of experimental jab being developed in France and Germany, it was revealed yesterday.

Agreement has been reached for 30million doses from German firm BioNTech and the US company Pfizer, and 60million doses from France’s Valneva. 

Britain is shoring up stocks of vaccines in development all over the world in its spread-betting approach in the hope that at least one of them will pay off.   

HOW MIGHT THE CORONAVIRUS VACCINE WORK? 

Human trials of the coronavirus vaccine candidate being developed at the University of Oxford are looking promising. 

It is thought that early results indicate the jab could provide double protection – generating an immune response which stimulates the body to produce both antibodies and ‘killer T-cells’.

But what does the vaccine do, how does it work, and what happens next? 

What is the vaccine? 

The vaccine – called AZD1222 – uses a weakened version of a common cold virus (adenovirus) which causes infections in chimpanzees. It has been genetically changed so it is impossible for it to grow in humans. 

Researchers hope their version will make the body recognise and develop an immune response to the spike protein – recognisable in images of the virus – that will help stop Covid-19 from entering human cells and therefore prevent infection. 

What do the early results suggest? 

The researchers published the results of their Phase 1 clinical trials in The Lancet on July 20.

They revealed that the Covid-19 vaccine had been given to 543 people out of a group of 1,077. The other half were given a meningitis jab so their reactions could be compared and scientists could be sure the effects of the coronavirus jab weren’t random.

Researchers wanted to find out whether the vaccine boosted either of two types of immunity — antibodies, which are disease-fighting substances; and T-cell immunity, with T cells able to produce antibodies and also to attack viruses themselves. 

The vaccine produced ‘strong’ responses on both accounts, the study found.

It showed that the T cell response aimed at the spike protein that appears on the outside of the coronavirus was ‘markedly increased’ in people who had had the jab, in tests of 43 of the participants. These responses peaked after 14 days and then declined before the end-point of the trial at 56 days.

Antibody immunity, on the other hand, peaked after four weeks and remained high by day 56, the point at which the last measurement was taken, meaning it may well last for even longer.

After 28 days, up to 100 per cent of a group of 35 people still had a strong enough ‘neutralising’ immune response to destroy the virus, researchers found.

A neutralising response means the immune system is able to destroy the virus and make it unable to infect the body.

The researchers could not test this on more people because they didn’t have enough time, they explained. 

It is not yet known whether the Oxford vaccine candidate provides long-term immunity. 

How are the trials progressing? 

More than 4,000 participants are already enrolled in the UK, with enrolment of a further 10,000 people planned as researchers test the ChAdOx1 nCoV-19 vaccine. 

Trials are also taking place in South Africa and Brazil and it is hoped an effective vaccine could be ready later this year. 

This trial aims to assess how well people across a broad range of ages could be protected from Covid-19. 

It will also provide valuable information on safety aspects of the vaccine and its ability to generate good immune responses against the virus. 

Do enough people in the UK have Covid-19 in order for trials to show efficacy? 

Professor Sarah Gilbert, who is leading the Oxford research, has said low transmission rates in the UK mean there is ‘little chance’ of trials in the country proving the effectiveness of a coronavirus vaccine. 

A sufficient number of volunteers have to be exposed to the virus to see whether a vaccine protects them or not. 

However, if their chances of being in contact with an infected person are low, it will take a long time to demonstrate the efficacy of a vaccine candidate. 

What can be done to combat this? 

Researchers have started trialling the vaccine in countries where there is a higher infection rate. 

But some are calling for challenge trials, which involve deliberately exposing people to the virus after giving them the vaccine. 

A number of prominent scientists, including Nobel laureates, are calling for volunteers to be exposed to coronavirus after receiving a vaccine to see if it offers protection. 

They have signed an open letter to the head of the US National Institutes of Health (NIH), saying these challenge trials could accelerate vaccine development. 

The signatories, who include Adrian Hill, director of the Jenner Institute at Oxford where the vaccine was developed, are calling on the NIH, its allies, international funders, and world bodies like the World Health Organization, to undertake immediate preparations for human challenge trials. 

They suggest this should involve supporting safe and reliable production of the virus and any biocontainment facilities necessary to house participants. 

The authors write: ‘If challenge trials can safely and effectively speed the vaccine development process, there is a formidable presumption in favour of their use, which would require a very compelling ethical justification to overcome.’ 

In the letter the signatories also set out principles for a challenge trial, including an ethical and scientific review. 

If a successful vaccine is developed, can it be manufactured to scale? 

Production of the vaccine has already been scaled up ahead of the trial to prepare as early as possible for potential future deployment. 

AstraZeneca has reached an agreement with Europe’s Inclusive Vaccines Alliance (IVA) to supply up to 400 million doses of the University of Oxford’s Covid-19 vaccine at no profit, with deliveries starting by the end of 2020. 

The British Government has agreed to pay for up to 100 million doses, adding that 30 million may be ready for UK citizens by September.

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