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How will the coronavirus vaccine trial work?

Volunteers are being recruited for the next two phases of clinical trials to help develop a coronavirus vaccine this year.

Work began in January on the vaccine, which uses a virus taken from chimpanzees and has been developed by the University of Oxford’s Jenner Institute and the Oxford Vaccine Group.

If it proves successful in human trials, up to 30 million doses for the UK could be available by September, the Government has said.

But what does the trial involve, and how will it work according to the Oxford Vaccine Group?

– What is the purpose of the study?

The trial will analyse whether healthy people can be protected from Covid-19 with the vaccine created by the Oxford Vaccine Group – ChAdOx1 nCoV-19.

It will allow researchers to assess the safety of the candidate, and its ability to generate an immune response.

– How does the study work?

Researchers want to recruit up to 10,260 people across the country for phases two and three of the study to see if there is a variation in how the immune systems responds to the vaccine in older people and children.

The volunteers will be randomly allocated to receive either the ChAdOx1 nCoV-19 vaccine or a licensed meningitis vaccine that will be used as a control for comparison.

The first phase of the trials involved 160 healthy volunteers aged between 18 and 55.

Coronavirus-related deaths in hospitals in England (PA Graphics)
Coronavirus-related deaths in hospitals in England (PA Graphics)

– Who can participate?

Researchers are seeking volunteers aged 56 and over, as well as children aged five to 12 for phase two, and people aged 18 and over for phase three.

They cannot have tested positive for Covid-19, must be in good health, not be pregnant or breastfeeding, and must not have previously taken part in a trial with an adenoviral vaccine or received any other coronavirus vaccines.

The trial is being conducted across the country, with sites in Bristol, Sheffield, London and Birmingham.

Vaccinations will take place in May and June this year.

– How will the trial work?

The dose used in the trial has been chosen based on previous experiences with other ChAdOx1 based vaccines.

Participants will not know whether they have received the Covid-19 vaccine or the control vaccine until the end of the trial.

Depending on which group they are allocated, some volunteers may have to attend up to 12 appointments over 12 months, while others will be limited to six.

Global coronavirus cases and deaths (PA Graphics)
Global coronavirus cases and deaths (PA Graphics)

– What happens next?

The participants will be given an e-diary to record any symptoms they experience in the seven days after receiving the vaccine.

They will also record if they feel unwell for the following three weeks.

The volunteers will attend a series of follow-up visits, during which blood samples will be taken to assess their immune response, and their observations checked.

If they develop Covid-19 symptoms during the study, they can contact a member of the clinical team, who will check if they have become infected with the virus.

If a participant becomes very unwell they will be reviewed by staff at the hospital.

– When will the results be available?

The statisticians will compare the number of infections in the control group with the number of infections in the vaccinated group.

Therefore, it is necessary for a small number of study participants to develop Covid-19.

How quickly researchers reach the numbers required depends on the levels of virus transmission in the community.

If transmission remains high, enough data may be available in a couple of months but if transmission levels drop, this could take up to six months.

– What is the vaccine?

ChAdOx1 nCoV-19 is made from ChAdOx1, which is a weakened version of a common cold virus (adenovirus) that 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 that will help stop Covid-19 from entering human cells and therefore prevent infection.

– What other trials are taking place?

Frontline health workers in the UK are able to participate in a global trial to test if the malaria drug touted by US president Donald Trump prevents coronavirus.

The testing of chloroquine or hydroxychloroquine is open to staff in Brighton and Oxford as part of an investigation led by the Bangkok-based Mahidol Oxford Tropical Medicine Research Unit (Moru).

Scientists say the drug has some “very serious” side-effects and there is no evidence that it prevents or treats the disease.

But those running the Moru trial have said chloroquine and hydroxychloroquine “could reduce the chances” of catching coronavirus.

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