Scientists Test a New COVID-19 Vaccine Question: Mixing Different Doses

The Wall Street Journal reports that scientists are wondering whether mixing COVID-19 vaccine doses from different manufacturers could improve immune response. Researchers say heterologous prime-boost vaccination could enable the immune system to fight an invader in multiple ways, and perhaps reduce the odds of the immune system repelling a vaccine with the second of two shots under a conventional approach. This strategy has been deployed successfully in the past with Ebola, malaria, and other infectious diseases. The hope with COVID-19 is that mix-and-match dosing not only will offer more protection against emerging variants, but also mitigate supply shortages by giving administrators additional options when patients present for the second part of their inoculation. The University of Oxford is enlisting volunteers for a study that will evaluate a dual combination of the AstraZeneca vaccine, which it helped develop, and the Pfizer-BioNTech vaccine. AstraZeneca also plans to investigate how its product works in combination with the Sputnik V vaccine from Russia.