Incidence of acute diarrhoea among children (0-59 months old) in Thailand after introduction of rotavirus vaccine: a retrospective national database analysis (2014-2024).

Sailuenarm, Thanate; Phongsamart, Wanatpreeya; Bhunyakitikorn, Wichan; Doungngern, Pawinee; Lapphra, Keswadee; Wittawatmongkol, Orasri; Rungmaitree, Supattra; Lertamornkitti, Nichkamol et al. · Lancet Reg Health Southeast Asia · 2026

retrospective_cohort · Level III

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Abstract

Rotavirus vaccination has reduced incidence of childhood diarrhoea, but evidence from low- and middle-income countries remains limited. We evaluated diarrhoea incidence and hospitalisation rates among children aged 0-59 months after introduction of rotavirus vaccination in Thailand's national immunisation programme (February 2020-December 2024). We analysed aggregated national surveillance data (ICD-10-TM: A00-A09, K56.1) from Thailand's Health Data Centre (covering ≈90% of public health facilities), including inpatient, outpatient, and death records. Diarrhoea incidence and hospitalisation rates were assessed using Poisson regression to estimate incidence rate ratios (IRRs) among children 0-59 months of age with acute diarrhoea and among 0-11 months with intussusception. Vaccine impact was assessed by comparing pre-vaccination (2014-2019) and post-vaccination (2021-2024) periods, excluding the year 2020. Analyses were age-stratified as proxies for differential vaccine exposure across birth cohorts under the immunisation program. Individual-level demographic characteristics were not available. All-cause and rotavirus-associated diarrhoea incidence declined by 50.0% (IRR 0.50; 95% CI 0.39-0.63) and 52.0% (IRR 0.48; 95%CI 0.39-0.59), respectively, following rotavirus vaccine introduction. Hospitalisation for all-cause and rotavirus-associated diarrhoea decreased by 58.2% (IRR 0.42; 95% CI 0.30-0.58) and 49.0% (IRR 0.51; 95%CI 0.30-0.88), respectively, at 1-4 years post-vaccination. All-cause acute diarrhoea mortality did not differ significantly during pre- and post-vaccination periods (IRR 0.94; 95% CI 0.50-1.77); rotavirus-specific mortalities were too few to analyse. Following vaccine introduction, seasonal peaks between December and February became less pronounced. Intussusception rates remained stable during the post-vaccination period (IRR 1.03; 95% CI 0.82-1.29). This study demonstrated a significant decline in incidence and hospitalisation of all-cause and rotavirus-associated diarrhoea among children (0-59 months). Sustaining high coverage is essential to maximise public health benefits from vaccination. None.