Oxford Covid vaccine is 70% effective on average, new data shows

The Oxford University coronavirus vaccine has been found to be 70% effective on average.

The vaccine, which has been developed alongside pharmaceutical giant AstraZeneca, has now been submitted to the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) for approval.

Results from all studies pooled together show the vaccine was 70.4% effective, on average, in preventing Covid-19 after two doses were given.

Scientists noted there were no admissions to hospital or severe disease in people receiving the vaccine, saying this injection will help control the pandemic.

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.’

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.

This means 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.

Writing in The Lancet medical journal, scientists said more research is needed on how effective the vaccine is in older adults, who are at most risk of severe Covid-19.

Testing so far has been mostly restricted to people aged under 55, with work in older age groups still ongoing.

Researchers added while five cases of Covid-19 occurred in people aged over 55, the effectiveness of the vaccine in older age groups could not be assessed at the moment as there were too few cases.

Study author Dr Merryn Voysey, from the University of Oxford, said: ‘The results presented in this report provide the key findings from our first interim analysis.

‘In future analyses, with more data included as it becomes available, we will investigate differences in key subgroups such as older adults, various ethnicities, doses, timing of booster vaccines, and we will determine which immune responses equate to protection from infection or disease.’

In its product profile for coronavirus vaccines, the World Health Organisation sets 50% at its minimum effectiveness criteria.

Modern flu vaccines are usually between 40% and 60% effective and greatly reduce infection numbers among the population.

Flu rates are down 90% this year, due to a combination of an increased uptake in the vaccine, social distancing and better hygiene measures.

‘Control of the pandemic will only be achieved if the licensing, manufacturing and distribution of these vaccines can be achieved at an unprecedented scale and vaccination is rolled out to those who are vulnerable,’ added Professor Pollard.

‘Our findings indicate that our vaccine’s efficacy exceeds the thresholds set by health authorities and may have a potential public health impact.’

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.

This included 30 out of 5,807 (0.5%) cases in the vaccine group and 101 out of 5,829 (1.7%) cases in the control group, which equates to a vaccine efficacy of 70%.

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 further carried out a sub-analysis to better 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.

They concluded, 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.

But they said this data ‘provides a suggestion’ and more research is needed.

The Pfizer/BioNTech vaccine, which was approved by the UK last week and the first person in the world was given it this morning, is up to 95% effective.

But it is more difficult to administer logistically, as it must be stored at -70C and can only be moved four times.

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