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Posted on Jul 21 2020 by Jo Lehmann

Coronavirus: When will the Oxford trial vaccine really be available?

On Monday the University of Oxford announced that a coronavirus vaccine it developed appears safe and triggers an immune response. The trials involving 1,077 people showed the injection led to them making antibodies and T-cells that can fight coronavirus.

Kieran Breen, Head of Research at St Andrew's Healthcare explores what this announcement means and how much closer we are to getting a vaccine which is ready for public use.

"One of the key aims of the first phase of a trial for any medicine is to ensure that it is safe. So over 1,000 healthy people were administered two doses of an inactive form of the vaccine on day 1 and 28 days later.

These were then followed for a further 28 days and blood samples were taken. These were analysed for the presence of antibodies against the virus and also an immune cell response. In all cases, there was a positive reaction that means that the body recognised the inactive virus as “foreign” and reacted against it. There were very few side effects and these could be controlled by paracetamol.

This is really good news as it means that this form of the virus can generate an immune response which lasts for up to two months. So, the vaccine is safe and it is effective.

The next stage will be critical, as longer term monitoring will tell us whether this immune response is maintained and how strong it is. Normally in a drug trial, the early stages are carried out in people without a disease to assess the safety, termed “controls”, and then the drug is given to people with the condition to see whether it is effective in treating it.

However, it would not be ethical to infect these people with the coronavirus as, if the immune response that it has generated is not sufficient, they may actually develop COVID-19 with significant consequences.

So, the researchers will vaccinate a large number of people in countries where there is currently a high level of the virus (South Africa and Brazil) in order to determine whether there is a lower incidence of the disease among those vaccinated when compared with those who were not vaccinated. This will take a number of months and will involve a large number of people, so results will not be expected until later in the year.

The other factor to be considered is that all of the people who took part in this first trial were healthy adults aged 18–55 years. But, the groups who are likely to benefit most from the vaccine initially are those who were self-isolating during lockdown – the elderly or people who have conditions who would make them more susceptible to reacting to COVID-19. So, these will also be tested for safety of the vaccine over the coming months. Although younger healthy people had few side effects, we need to show that it is safe in the more vulnerable population before it is made available.

While I am cautiously optimistic about the results so far, I have previously seen drugs being very positive at an early stage, only to fall at a later hurdle. So we need to take this one step at a time.

Also, we need to consider that there are at least 20 other vaccines being tested, all of which use a slightly different approach and I look forward to seeing their results once they are published."