Oxford, Pfizer test vaccine mix to boost protection
Trials are being planned in Britain to ‘‘mix and match’’ vaccines to see if combining the Oxford and Pfizer jabs produces a stronger immune response.
The head of the Vaccine Task Force said yesterday that if, as expected, the Oxford-astrazeneca vaccine were approved soon for use, small studies would be conducted in the new year to see if the two could be used together.
Instead of a first shot of the Pfizer vaccine followed by a booster three weeks later, the trials will look at using Pfizer for the first shot then Oxford for the second . . . or vice versa.
The hope is that the two approaches could complement each other. Kate Bingham, chairwoman of the Vaccine Task Force, responsible for buying Britain’s vaccines, said: ‘‘The idea is that you can maximize the strength of that immune response to protect people.’’
Both vaccines target the same ‘‘spike’’ protein on the coronavirus but they do so in different ways. The Oxford vaccine is based on a chimpanzee adenovirus, that carries genetic material into cells. The PfizerBiontech vaccine uses MRNA to interfere with their signals.
This means that they affect the immune system in different ways, with the Oxford vaccine producing more T-cells – a different arm of immunity from antibodies. Bingham explained: ‘‘Antibodies block the uptake of viruses into cells and the cellular T-cells identify those cells that have been infected and take them out. You ideally want to have both.’’
Clive Dix, deputy chairman of the task force, said that they were working on protocols. He anticipated that only small trials would be needed, involving blood tests after a month for immune responses. He said that having a combination of vaccines might make logistics easier.
Bingham, a venture capitalist, was speaking at the end of her tenure heading the group. She was brought in to secure a portfolio of vaccines for Britain, and was the first to strike a deal for the Pfizer vaccine.
She said that Britain gaining the first vaccine in use was in part because of the unusual decision to take it out of the hands of the civil service. ‘‘It’s been uncomfortable but bringing private sector experts into government to get the job done quickly has worked well,’’ she said.
‘‘The challenge has been working with people in government who have very little knowledge of what we’re doing. So, if you look at the numbers of scientists, or people with industrial experience in [the Department for Business, Energy and Industrial Strategy], they’re just not there.
‘‘It’s difficult getting business cases written, when people don’t automatically know what ’clinical trials’ means or what ’manufacturing’ means . . . a lot is lost between the lines because the people we are working with don’t get it.’’
As well as the Oxford and Pfizer vaccines, Britain has bought more than 200 million doses of five other vaccines, across a range of technologies.
The other vaccines use more conventional techniques, with better understood long-term safety and efficacy profiles. They include the Valneva vaccine, which uses an inactivated form of the virus and will be manufactured in Britain.