The Oxford coronavirus vaccine is more effective at longer prime-boost intervals, with a single dose having an efficacy rate of 76% from 22- up to 90-days post vaccination, researchers at the University of Oxford have found.

Additionally, the Oxford vaccine may be effective in reducing transmission of coronavirus. Based on swabs obtained from volunteers in the UK, there was a 67% reduction in positive tests among those who had been vaccinated.

Professor Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial, and co-author, said in a press release: “These new data provide an important verification of the interim data that was used by more than 25 regulators including the MHRA and EMA to grant the vaccine emergency use authorisation.

“It also supports the policy recommendation made by the Joint Committee on Vaccination and Immunisation (JCVI) for a 12-week prime-boost interval, as they look for the optimal approach to roll out, and reassures us that people are protected from 22 days after a single dose of the vaccine.”

Based on these findings, the dosing interval, rather than the dosing level, has a greater impact on vaccine efficacy. Previous research on other vaccines such as influenza, Ebola, and malaria have also shown increased efficacy with longer prime-boost intervals.

At the same time, Oxford University is leading the first trial to investigate dosing with alternative vaccines for the initial ‘prime’ vaccination to the follow-up ‘booster’ vaccination. The study is conducted by the National Immunisation Schedule Evaluation Consortium (NISEC), and is backed by £7 million of government funding from the Vaccines Taskforce. 

Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator on the trial said in a press release, “If we do show that these vaccines can be used interchangeably in the same schedule this will greatly increase the flexibility of vaccine delivery, and could provide clues as to how to increase the breadth of protection against new virus strains.

“This is a tremendously exciting study that will provide information vital to the roll out of vaccines in the UK and globally. We call on those aged 50 years and above who have not yet received a COVID-19 vaccine to visit the website to find out more about the study and see if there is a study site near them,” Professor Snape added.

The World Health Organisation (WHO) has recently announced that it backs the use of the Oxford vaccine, even with the presence of new variants of Covid-19. While some countries have advised against the use of the Oxford vaccine for over-65s, the WHO believes that the vaccine is suitable for this age group.

As of 9 February, over 13 million people in the UK have received their first dose of the coronavirus vaccine, while more than half a million have gotten their second dose, according to data from the government.


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