[Effectiveness of Lanzhou lamp rotavirus vaccine against rotavirus gastroenteritis in children based on propensity score matching test negative case-control design].

<b>Objective:</b> To evaluate the vaccine effectiveness (VE) of the Lanzhou lamb rotavirus vaccine (LLR) against rotavirus gastroenteritis (RVGE) in children using a propensity score-matched (PSM) test-negative case-control design. <b>Methods:</b> Based on electronic health records from medical institutions and the National Immunization Program Information System, demographic information, disease diagnoses, rotavirus pathogen test results, and rotavirus vaccination details (vaccine type, number of doses, dates) were collected for acute gastroenteritis cases aged 2 months to 4 years in Chaoyang District (Beijing), Guangdong Province, and Wuhan City (Hubei Province) from 2020 to 2024. Patients were divided into a case group (rotavirus-positive) and a control group (rotavirus-negative) based on etiological test results, and vaccination proportions were calculated for each group. To reduce effects of confounding factors, a PSM test-negative case-control design was employed. The VE of LLR against different clinical outcomes was calculated using a conditional logistic regression model, and the VE of LLR against healthcare visits for rotavirus infection across different age groups was calculated using a multivariate logistic regression model. <b>Results:</b> A total of 16 460 children with acute gastroenteritis aged 2 months to 4 years were collected, with an age [<i>M</i> (<i>Q</i>₁, <i>Q</i>₃)] of 1.4 (0.7, 2.7) years, and 9 713 (59.01%) were male. The number of children who received 1, 2, and 3 doses of LLR was 2 391 (14.53%), 894 (5.43%), and 180 (1.09%) cases, respectively. There were 1 799 cases (10.93%) in the case group. Among them, the majority were from Hubei Province (953 cases, 52.97%), with a visiting age of 2-4 years (947 cases, 52.64%), males (1 082 cases, 60.14%), in the outpatient department (1 430 cases, 79.49%), with a visiting month of April (574 cases, 18.73%), and with 0 doses of vaccination (1 523 cases, 84.66%). There were statistically significant differences in province, age, case type, month of visit and dose of vaccination between the case and the control groups (<i>P</i><0.001). After PSM matching, the VE (95%<i>CI</i>) of 1-dose and 2-dose LLR against the RVGE visits were 55.66% (45.83%-63.71%) and 59.37% (45.48%-69.72%), respectively, and for RVGE hospitalizations were 63.87% (38.96%-78.62%) and 82.95% (58.37%-93.01%), respectively. Multivariate logistic regression models analysis showed that among the RVGE visits, the VE of children aged 2 months to 1 year and 1 to 2 years after one dose of LLR was greater than that of children aged 2-4 years [54.96% (16.42%-78.62%) vs 59.29% (45.69%-69.98%) vs 49.53% (37.22%-59.75%), all <i>P</i><0.001]. <b>Conclusions:</b> LLR has a good protective effect on children aged 2 months to 4 years. Two doses provide better protection against rotavirus infection, especially for hospitalized patients with RVGE and children under 2 years old.