Dear Editor,I read with interest the recent article by Kant et al. published in Drug Safety [1]. Kant et al. concluded that “The analysis of a large cohort provides important information about the rates of AEFIs across age groups, among brands of vaccines and between those with and without prior COVID-19 infection. Participants reported a high number of AEFIs in general, but the frequency of serious AEFIs was low.” We agree that COVID-19 vaccines might cause adverse effects. However, to interpret the data on the frequency of adverse events following immunization (AEFIs) it is necessary to recognize the local availability of COVID-19 vaccines. Limited availability of vaccines in some settings might also be associated with a low frequency of reported AEFIs. For example, the reported AEFI rate of COVID-19 vaccines increased after greater availability of vaccines was observed in Bangalore, India [2]. Additionally, the verification system for AEFIs should be discussed. There is a chance of under-reporting as well as over-reporting. In a vaccine recipient, a clinical problem after vaccination might or might not be associated with the COVID-19 vaccine. For example, a vaccine recipient might experience dengue-related thrombocytopenia, which might be wrongly interpreted as an AEFI [3].