Researchers at the University of Oxford, UK, will start testing what happens when they give people a mix of different COVID-19 vaccines.
Amid the scarcity of vaccine supplies and the threat of emerging variants of the coronavirus, such an approach may provide an answer for both, according to a statement. The study, which will include more than 800 volunteers across England 50 years of age or older, is the first to look at a mixed approach to the COVID-19 vaccination.
Some participants will receive a first dose of the Oxford-AstraZeneca vaccine followed by a second dose of the same vaccine or the Pfizer vaccine; and some will receive the Pfizer vaccine followed by a second dose of the same vaccine or the Oxford-AstraZeneca vaccine.
Related: Quick guide: COVID-19 vaccines in use and how they work
Some participants will receive the two doses four weeks apart and others will receive the vaccines 12 weeks apart (which is in line with the UK policy to vaccinate as many people as possible and postpone the second dose by 12 weeks). Participants will periodically give blood samples and researchers will test the impact of the mixture and the combination on their immune responses and will also test for any adverse reactions.
“Given the inevitable challenges of immunizing large numbers of the population against COVID-19 and the potential global supply constraints, there are definite advantages to having data that could support a more flexible immunization program, if necessary and if approved by the regulator. medicines, “Dr. Jonathan Van-Tam, the deputy chief physician and senior officer responsible for the study, said in the statement. “It is also possible that when combining vaccines, the immune response can be increased, giving even higher levels of antibodies that last longer; unless this is evaluated in a clinical trial, we simply will not know.”
The Oxford-AstraZeneca and Pfizer vaccines were developed using two different approaches; to stimulate the immune system, the former uses a weakened adenovirus to deliver the genes of the spike protein and the latter uses messenger RNA encased in a nanoparticle.
It is not yet clear whether the administration of two very different vaccines would bring any benefit. The closest data we have to this is about the Russian vaccine Sputnik V, which was 91% effective in preventing COVID-19 and uses two slightly different versions of its vaccine for its two separate doses, according to the Associated Press. Still, both versions were developed using the same adenovirus-based technology.
If the study really shows that a combined approach is of great benefit, it will still be formally reviewed for safety and efficacy by the Medicines and Health Products Regulatory Agency (MHRA) before such an approach is adopted to vaccinate the rest to the public.
Currently, guidelines in the UK and the USA say that COVID-19 vaccines should not be used interchangeably unless the same type of vaccine is not available for a person’s second dose or if the person’s vaccine is unknown. received as the first dose, according to the AP.
The mix-and-match test is conducted by the UK National Immunization Schedule Assessment Consortium with government funding and will last for 13 months.
Originally published on Live Science.