Heterologous Oxford–AstraZeneca and BioNTech/Pfizer Vaccination induce increased levels of neutralizing antibody compared to 2 doses of Oxford–AstraZeneca.

Immune responses against SARS-CoV-2 variants after heterologous and homologous ChAdOx1 nCoV-19/BNT162b2 vaccination – Nature Medicine

Heterologous ChAdOx1 nCoV-19 and mRNA-1273 Vaccination – New England Journal of Medicine

Related: [Preprint] Mixing Covid jabs has good immune response, study finds – “The Com-Cov trial looked at the efficacy of either two doses of Pfizer, two of AstraZeneca, or one of them followed by the other. All combinations worked well, priming the immune system”. AND Phase 2 RCT: Immunogenicity and reactogenicity of a Pfizer-BioNTech booster in patients that have received a single dose of AstraZeneca vaccine – “BNT162b2 (Pfizer) given as a second dose in individuals prime vaccinated with ChAdOx1-S (AstraZeneca) induced a robust immune response, with an acceptable and manageable reactogenicity profile”. AND RCT: Mixing 2 different Covid vaccines is associated with increased risk of side effects.

Commentary on Twitter

Mix and match vaccines?
2 doses AZ vs AZ and then Pfizer:
"BNT162b2 induced significantly higher frequencies of spike-specific CD4+ and CD8+ T cells and, in particular, high titers of neutralizing antibodies against the B.1.1.7, B.1.351 and P.1 variants" https://t.co/53J2erWVMy pic.twitter.com/aEmqMlhEar

— Eric Topol (@EricTopol) July 14, 2021