COVID-19 Vaccine Side Effects in Children Aged 5-11 years in Thailand

Abstract

This research was conducted with the objective to study the incidence of adverse outcomes from getting vaccines against Coronavirus 2019 (COVID-19) among children aged between 5 and 11 years with the method of a retrospective, cross-sectional study. The sample was from kindergarten 1 to elementary grade 6 students (along with their guardians) living in Thailand who received at least 1 dose of the vaccine regardless of the brand. The total number of participants was 1,232 people from the simple random sampling method of the schools-name list in Thailand.  The data were collected from April to May 2022 via an online questionnaire as Google form, then were analyzed by both descriptive and inferential statistics with t-test and binary logistic regression to compare the incidence of side effects from COVID-19 vaccine between two age-group; of 5- to 8-year-old (kindergarten 1 to elementary grade 3) and 9- to 11-year-old (elementary grade 4 to 6). The result showed that there were 865 participants (70.21% of the total participants) reported at least 1 symptom of the side effects after vaccine administration within a month. The three most frequent reports of symptoms were local site pain (40.50%), myalgia (26.87%), and fatigue (12.42%). The older group suffered from adverse effects more than the younger one with the report of 563 people (71.99%) and 302 people (67.11%) respectively; however, the outcome showed no statistical difference significantly between these two groups in general (adjusted OR 1.26, 95%CI 0.96-1.64). The severity was more predominant among students who received the third dose than the first two doses. There was one patient admitted to a hospital with the diagnosis of myocarditis after COVID-19 vaccination; nevertheless, no fatal was reported for this study.