Reactogenicity after heterologous and homologous COVID-19 prime-boost vaccination regimens: descriptive interim results of a comparative observational cohort study

Abstract

Background Due to safety signals after vaccination with COVID-19 vector vaccines, several states recommended to complete the primary immunization series in individuals having received one dose of ChAdOx1 (AstraZeneca) with an mRNA vaccine. However, data on safety and reactogenicity of this heterologous regimen are still scarce. The aim of this study was therefore to compare the reactogenicity and the frequency of medical consultations after boost vaccination in a heterologous regimen with ChAdOx1 and mRNA-vaccines (BNT162b2, BioNTech/Pfizer or mRNA-1273, Moderna) to homologous regimens with ChAdOx1 or mRNA-vaccines, respectively. Methods In an observational cohort study reactogenicity and safety were assessed 14–19 days (short-term) and 40 to 56 days (long-term) after the boost vaccination using web-based surveys. In the short-term survey solicited and unsolicited reactions were assessed, while the long-term survey focussed on health problems leading to medical consultation after the vaccination, including those that were not suspected to be vaccine-related. Results In total, 9146 participants completed at least one of the surveys (ChAdOx1/ChAdOx1: n = 552, ChAdOx1/mRNA: n = 2382, mRNA/mRNA: n = 6212). In the short-term survey, 86% with ChAdOx1/mRNA regimen reported at least one reaction, in the ChAdOx1/ChAdOx1 and mRNA/mRNA cohorts 58% and 76%, respectively (age and sex adjusted p < 0.0001). In the long-term survey, comparable proportions of individuals reported medical consultation (ChAdOx1/ChAdOx1 vs. ChAdOx1/mRNA vs. mRNA/mRNA: 15% vs. 18% vs. 16%, age and sex adjusted p = 0.398). Female gender was associated with a higher reactogenicity and more medical consultations. Younger age was associated with a higher reactogenicity, whereas elderly people reported more medical consultations. Conclusion Although the short-term reactogenicity was higher with the heterologous regimen than with the homologous regimens, other factors such as higher efficacy and limited resources during the pandemic may prevail in recommending specific regimens.

Adverse Reactions after Booster SARS-CoV-2 Vaccination Have Less Impact on Antibody Response than after Basic Vaccination Scheme

“…Another potential mechanism of this phenomenon is that older people show a greater tolerance for pain and disease symptoms acquired through life [ 18 ]. We found that after the heterologous booster vaccination, there were more symptomatic patients than after the homologous 3rd dose, which corresponds to what is described in the literature [ 19 , 20 ]. According to a recent study, spike-specific CD8 T-cell levels after heterologous vaccination were significantly higher than after homologous regimens [ 21 ].…”

Safety Profile of Homologous and Heterologous Booster COVID-19 Vaccines in Physicians in Quito-Ecuador: A Cross-Sectional Study

“…They reported similar frequencies of adverse reactions during the first eight days after the second and third vaccination. They also found that the incidence of adverse reactions was significantly higher in heterologous vaccination compared to homologous vaccination [ 26 ], which is consistent with our results and several others that have been reported [ 27 , 28 , 29 ].…”

Sex-disaggregated outcomes of adverse events after COVID-19 vaccination: A Dutch cohort study and review of the literature

“…Nearly all articles reported a higher incidence of AEFIs in females compared to males with the exception of four articles which found an opposite outcome, for most of which no clear reason could be identified other than a possible skewed distribution of the sexes and age groups in the studies ( 17 , 18 , 80 , 85 ). Of the 21 articles which reported a OR of any adverse reaction for sex, the median OR was 1.93 (range: 0.85-3.45, IQR 1.49-2.50) using males as reference group ( Supplementary Table S8 ) ( 2 , 6 , 13 , 22 , 24 , 25 , 34 , 43 , 45 – 47 , 52 , 54 , 56 , 61 , 63 , 66 , 68 , 79 , 81 , 85 ). Similarly, females had a median 1.96 times higher odds of reporting a local reaction compared to males (range: 1.02-2.90, IQR1.85-2.54) ( 22 , 32 , 42 , 54 , 76 ).…”