Rotavirus vaccines have substantially decreased rotavirus hospitalizations in countries where they have been implemented. In some high- and middle-income countries, a low-level of increased risk of intussusception, a type of acute bowel obstruction, has been detected following rotavirus vaccination. However, no increased risk of intussusception was found in India, South Africa, or a network of 7 other African countries. We assessed the association between a 2-dose monovalent rotavirus vaccine (Rotarix) and intussusception in 3 early-adopter low-income Asian countries -- Afghanistan, Myanmar, and Pakistan. Children <12 months of age admitted to a sentinel surveillance hospital with Brighton level 1 intussusception were eligible for enrollment. We collected information about each child's vaccination status and used the self-controlled case series method to calculate the relative incidence of intussusception 1-7 days, 8-21 days, and 1-21 days following each dose of vaccine and derived confidence intervals with bootstrapping. Of the 585 children meeting the analytic criteria, the median age at intussusception symptom onset was 24 weeks (IQR: 19-29). Overall, 494 (84 %) children received the first Rotarix dose and 398 (68 %) received the second dose. There was no increased intussusception risk during any of the risk periods following the first (1-7 days: 1.01 (95 %CI: 0.39, 2.60); 8-21 days: 1.37 (95 %CI: 0.81, 2.32); 1-21 days: 1.28 (95 %CI: 0.78, 2.11)) or second (1-7 days: 0.81 (95 %CI: 0.42, 1.54); 8-21 days: 0.77 (95 %CI: 0.53, 1.16); 1-21 days: 0.78 (95 %CI: 0.53, 1.16)) rotavirus vaccine dose. Our findings are consistent with other data showing no increased intussusception risk with rotavirus vaccination in low-income countries and add to the growing body of evidence demonstrating safety of rotavirus vaccines.

BACKGROUND: Afghanistan introduced monovalent rotavirus vaccine (Rotarix) into its national immunisation schedule in January, 2018. While post-licensure studies have shown substantial declines in rotavirus gastroenteritis cases and deaths globally, there is little evidence of rotavirus vaccine effectiveness and impact from low-income countries in Asia. We aimed to evaluate the effectiveness of the Rotarix vaccine and the impact of Rotarix vaccine on rotavirus gastroenteritis hospitalisations (ie, hospital admissions) among children younger than 5 years in Afghanistan. METHODS: We used a test-negative case-control design embedded in an active sentinel surveillance platform to evaluate vaccine effectiveness. Children born on or after Jan 1, 2018, who had documentation of their rotavirus vaccination status and who were admitted for acute gastroenteritis at one of four sentinel hospitals from May, 2018 to December, 2021 were eligible to be included. We used an unconditional logistic regression model to estimate vaccine effectiveness and 95% CIs for a complete series of doses compared with no rotavirus vaccine doses among patients admitted with acute gastroenteritis. Vaccine effectiveness against hospitalisation was calculated as (1 - [odds of being vaccinated in cases] / [odds of being vaccinated in controls]) × 100%. We compared pre-vaccine (2013-15) and post-vaccine (2019-21) surveillance data from two sites to calculate vaccine impact. FINDINGS: The vaccine effectiveness analysis included 1172 cases and 2173 controls. Approximately 2108 (63·0%) of 3345 cases and controls were male, 1237 (37·0%) were female, and 2171 (65·0%) were aged 6-11 months. Two doses of Rotarix were 45% (95% CI 22-62) effective against rotavirus hospitalisation in children aged 6-59 months, adjusting for age, severity, admission year, and rotavirus season. Rotavirus positivity decreased from 51% pre-vaccine to 39% post-vaccine, resulting in a 39% adjusted reduction in rotavirus positivity among children younger than 5 years admitted with acute gastroenteritis. INTERPRETATION: Rotarix showed moderate effectiveness in preventing rotavirus gastroenteritis hospitalisations, consistent with findings in other low-income countries. These findings support the continued administration of the rotavirus vaccine in Afghanistan. FUNDING: Gavi, the Vaccine Alliance. TRANSLATION: For the Dari translation of the abstract see Supplementary Materials section.

INTRODUCTION: Latin American countries were among the first to adopt rotavirus vaccines into national immunization programs; we reviewed one decade of their experience with rotavirus vaccination. Areas covered: We systematically reviewed manuscripts published January 1990-January 2018 to assess rotavirus vaccine effectiveness (VE) via meta-analysis; describe trends in rotavirus and acute gastroenteritis (AGE)-associated hospitalizations and mortality before and after vaccine introduction; and estimate annual hospitalizations and deaths averted by rotavirus vaccination in Latin American and Caribbean children <5 years. Rotavirus vaccines demonstrated VE against rotavirus hospitalization of 76% (95% CI: 58-87) in low-mortality countries and 67% (95% CI: 54-76) in high-mortality countries for children <1 year of age. Reductions of 64.0% (IQR: 49.9-69.2) were observed in rotavirus hospitalizations, 32.8% (IQR 29.0-40.3) in AGE hospitalizations, and 53.5% (IQR: 40.4-57.1) in AGE-related mortalities in children <5 years. In 2015, an estimated 125,000 rotavirus-associated hospitalizations and 800 rotavirus-related deaths were prevented in countries that implemented rotavirus vaccines. Expert Commentary: Rotavirus vaccines remain an effective tool against diarrheal disease. The continued success of rotavirus vaccines provides evidence for adoption in Latin American and Caribbean countries that have not yet introduced it, and improvement within those with low coverage.