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 method of schools’ name lists 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.