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
Health care workers who had received a dose of ChAdOx1 nCoV-19 were offered either ChAdOx1 nCoV-19 or mRNA-1273 9 to 12 weeks later. Levels of S-specific and RBD-specific IgG increased by a factor of 5 after ChAdOx1 nCoV-19 and by a factor of 115 to 125 after mRNA-1273.
— NEJM (@NEJM) July 14, 2021