RESUMEN
Background: The safety profiles of the Ad26.COV2.S and AZD1222 COVID-19 vaccines have not been described in a general population in Malawi. We present self-reported adverse reactions (AE) following receipt of these vaccines in Malawi as part of a phone-based syndromic surveillance survey. Method(s): We conducted phone-based syndromic surveillance surveys among adults (>=18 years) with verbal consent from July 2020 to April 2022. We used secure tablets through random digit dialing to randomly select mobile phone numbers and electronic data collection forms. Survey questions included whether the respondent had received at least one dose of the COVID-19 vaccines, whether they had experienced any AE following vaccination, and the severity of the AE. We used multivariable analysis to identify factors associated with self-reported adverse reactions post-COVID-19 vaccination. Result(s): A total of 11,924 (36.0%) out of 33,150 participants reported receiving at least one dose of either Ad26.COV2.S or AZD1222 between July-December 2021;65.1% were female. An estimated 49.2% of the vaccine recipients reported at least one AE, 90.6% of which were mild, and 2.6% were severe. About 16.9% (n=656) of respondents who received the first dose of AZD1222 had AE, while 50.2% (n=2,823) of those who received the second dose of AZD1222 and nearly all individuals (n=2,385) who received Ad26.COV2.S reported AE. Joint pain (45.5%), fever (26.7%), headache (26.1%), pain at the injection site (24.4%), and fatigue (16.6%) were among the commonly reported AE. Males were less likely to report an AE compared to females [Adjusted Odds Ratio (AOR) 0.81 95% confidence interval (CI) 0.75-0.88]. Older age was associated with reduced odds of an AE compared to those aged 18-24 years: 65 years+ (AOR 0.62, 95% CI 0.50- 0.77). The likelihood of reporting AE increased with education level: tertiary education AOR 2.63 95% CI 1.96-3.53. Respondents who thought COVID-19 vaccines were not safe were more likely to report post-vaccination adverse reactions than those who thought it was very safe (AOR 1.44, 95% CI 1.30-1.61). Conclusion(s): Ad26.COV2.S and AZD1222 vaccines are well-tolerated, with primarily mild and few severe AE among adults living in Malawi. Self-report of AE following COVID-19 vaccine receipt is associated with gender, age, education, and concern about the safety of the vaccines. Recognizing these associations is key when designing and implementing COVID-19 vaccination communication messages to increase vaccination coverage.