Real World Data Demonstrating Increased Reactogenicity in Adults Receiving Heterologous Compared to Homologous Prime-Boost COVID-19 Vaccination: March-May 2021, England
24 Pages Posted: 13 Jul 2021
Date Written: July 6, 2021
Adults receiving heterologous prime-boost COVID-19 immunisation schedules with mRNA (Pfizer-BioNTech) or adenoviral-vector (ChAdOx1-S/nCOV-19) vaccines had higher reactogenicity rates and were more likely to seek medical attention after their second dose than homologous schedules. Reactogenicity rates were generally higher among ≤50 than >50 year-olds and in adults with prior symptomatic or confirmed COVID-19. Adults receiving heterologous schedules because of severe first-dose reactions had lower reactogenicity after the second dose following ChAdOx1-S/Pfizer-BioNTech (93.4%[90.5-98.1] vs. 48%[41.0-57.7]) but not Pfizer-BioNTech/ChAdOx1-S (91.7%[77.5-98.2] vs. 75.0%[57.8-87.9]).
Note: Funding: This surveillance was internally funded by PHE and did not receive any specific grant funding from agencies in the public, commercial or not-for-profit sectors.
Declaration of Interests: The authors declare no conflict of interests
Ethics Approval Statement: PHE has legal permission, provided by Regulation 3 of The Health Service (Control of Patient Information) Regulations 2002, to process patient confidential information for national surveillance of communicable diseases and as such, individual patient consent is not required to access records. Individual patient consent was obtained by those who completed the questionnaire.
Keywords: Reactogenicity, heterologous schedule, COVID-19 vaccine
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