UK Launches Trial Giving Volunteers Alternating Pfizer and AstraZeneca COVID-19 Vaccine Doses

"Backed by £7 million [$9.5 million] of government funding, the study will be the first in the world to determine the effects of using different vaccines for the first and second dose – for example, using Oxford University/AstraZeneca’s vaccine for the first dose, followed by Pfizer/BioNTech’s vaccine for the second", the department said in a press release.

The study is being run by the National Immunisation Schedule Evaluation Consortium and will also assess the effects of giving participants a mixed-vaccine regimen at varying intervals.

"This is a hugely important clinical trial that will provide us with more vital evidence on the safety of these vaccines when used in different ways", Nadhim Zahawi, the UK's minister for COVID-19 vaccine deployment, said in the press release.

The government said that there were no current plans to alter the UK's national COVID-19 vaccination programme, which sees individuals receive two shots of the same vaccine.

Russian vaccine manufacturers have also raised the possibility of conducting mixed-dose trials. Kirill Dmitriev, the CEO of the Russian Direct Investment Fund, said in early January that plans were in place to conduct mixed Sputnik V-AstraZeneca dosing regimen trials.