Oxford researchers say having AstraZeneca then Pfizer vaccine is almost as potent as two shots of Pfizer.

Scientists in Oxford looked at the impact of a mix-and-match approach to vaccinations where people were given either the standard two shots of Oxford/AstraZeneca or Pfizer/BioNTech vaccine, or a combination of the two.

Mixed schedules involving Pfizer-BioNTech and Oxford-AstraZeneca generate strong immune response against SARS-CoV2 spike IgG protein

Doses administered four weeks apart; data for 12-week dose interval due soon.

Immune responses differed according to order of immunisation, with Oxford-AstraZeneca followed by Pfizer-BioNTech generating the better immune response out of the two mixed schedules.

University of Oxford-led Com-COV study report published on the Lancet pre-print server, that both ‘mixed’ schedules (Pfizer-BioNTech followed by Oxford-AstraZeneca, and Oxford-AstraZeneca followed by Pfizer-BioNTech) induced high concentrations of antibodies against the SARS-CoV2 spike IgG protein when doses were administered four weeks apart.

This means all possible vaccination schedules involving the Oxford-AstraZeneca and Pfizer-BioNTech vaccines could potentially be used against COVID-19.

‘The results show that when given at a four-week interval both mixed schedules induce an immune response that is above the threshold set by the standard schedule of the Oxford/AstraZeneca vaccine.

Note: That the order of vaccines made a difference, with an Oxford-AstraZeneca/Pfizer-BioNTech schedule inducing higher antibodies and T-cell responses than Pfizer-BioNTech/Oxford-AstraZeneca, and both of these inducing higher antibodies than the licensed, and highly effective ‘standard’ two-dose Oxford-AstraZeneca schedule.

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