Researchers confirm Oxford/ AstraZeneca Covid vaccine is safe and effective

Researchers have confirmed that the Oxford/ AstraZeneca Covid vaccine is safe and effective as well as providing good protection.

Prime minister Boris Johnson visits the Jenner Institute in Oxford where scientists are developing a Covid 19 vaccine. (Pic: Getty Images)

According to the scientist leading the study, Oxford University's Covid-19 vaccine "has a good safety record and efficacy" and could help control the pandemic.

The news comes as phase three data was published.

Interim results from pooled studies show the vaccine was 70.4% effective, on average, in preventing coronavirus after two doses were given.

For people given two full doses of the jab in one study, the vaccine was 62.1% effective. In a study where people received a half dose followed by a full dose, the vaccine was 90% effective.

The overall efficacy of 70.4% is based on 11,636 volunteers across the United Kingdom and Brazil, and combined across three groups of people vaccinated.

Data for the vaccine has been submitted to the UK's Medicines and Healthcare products Regulatory Agency (MHRA) for approval.

Professor Andrew Pollard, director of the Oxford Vaccine Group and chief investigator of the Oxford vaccine trial, said: "Today we have published the interim analysis of the phase three trial and show that this new vaccine has a good safety record and efficacy against the coronavirus.

"We are hugely grateful to our trial volunteers for working with us over the past eight months to bring us to this milestone."

Writing in the peer-reviewed medical journal, The Lancet, researchers said there were no admissions to hospital or severe disease in people receiving the vaccine.

However, they said more detail is needed on how effective the vaccine is in older adults - those at most risk of severe Covid-19.

The data in The Lancet analysis was mostly restricted to people aged 55 and under, with work in older age groups still ongoing.

Professor Sarah Gilbert, professor of vaccinology at the University of Oxford, said: "Following the demonstration of vaccine efficacy in many preclinical studies, we now have clear evidence of efficacy in the trial results presented in a peer-reviewed publication today.

"Now under regulatory review, we hope that this vaccine will shortly be in use to start saving lives."

In the study, there were 131 cases of Covid-19 in the 11,636 people taking part.

When breaking this down based on vaccine dose, those who received two full doses of the vaccine saw a vaccine efficacy of 62.1%, based on 27 out of 4,440 cases in the vaccine group, and 71 out of 4,455 cases in the control group.

In the group where people received a half dose followed by a full dose, vaccine efficacy was 90%, based on three out of 1,367 cases in the vaccine group, and 30 out of 1,374 cases in the control group.

Researchers carried out a sub-analysis to understand whether the difference between 62% efficacy and 90% was to do with the dose or other factors such as age and time between vaccine dose.

The researchers concluded that, irrespective of age or time between doses, the people given the half dose followed by the full dose had better odds of protection against Covid-19.

However, they said this data "provides a suggestion" and more research is needed as further cases are identified.

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