Abstract:
Objective To understand the protective effect of pentavalent rotavirus (RV) vaccine in preventing infectious diarrhea among infants and young children, and to provide a basis for formulating prevention and control strategies for this population.
Methods A retrospective cohort study was conducted to follow up resident children born in Pinghu City from January 2019 to June 2021 for two years. Data on morbidity and pentavalent RV vaccine inoculation were collected to analyze the incidence density of rotavirus infection among children inoculated with different doses of the pentavalent RV vaccine, and to calculate the vaccine protection rate.
Results A total of 5 141 resident children were surveyed, with a RV vaccination rate of 31.63% and a full vaccination rate of 30.83%. There were 154 cases of RV infection, with an incidence density of 1 392.69/100 000 person-years. Among the 875 migrant children (17.02%), the full vaccination rate was 20.46%, while among the 4 266 local children (82.98%), the full vaccination rate was 32.96%. The difference in full vaccination rate between migrant children and local children was statistically significant (χ2=53.209, P<0.001). The proportions of boys and girls were 51.94% and 48.06%, respectively, with a full vaccination rate of 29.74% and 32.01%, respectively; and the difference was not statistically significant (χ2=3.111, P=0.078). The proportions of children with normal birth weight and abnormal birth weight were 91.56% and 8.44%, respectively, with a full vaccination rate of 31.82% and 20.05%, respectingly; and the difference was statistically significant (χ2=25.852, P<0.001). Among the 3 515 children who were not vaccinated with the pentavalent RV vaccine, 118 of which were infected, with an incidence density of 1 503.32/100 000 person-years (with an incidence rate of 3.36%). Among the 41 children who were partially vaccinated (received only 1-2 doses), the incidence density was 1 058.54/100 000 person-years (with an incidence rate of 2.44%). Among the 1 585 fully vaccinated children, 35 of which were infected, with an incidence density of 1 123.96/100 000 person-years (with an incidence rate of 2.21%); and the difference in incidence rate was statistically significant (χ2=4.988, P=0.026). The protection rate for partial vaccination was 28.00% (95%CI:22.00%‒33.50%), while for full vaccination was 35.10% (95%CI: 29.80%‒40.00%).
Conclusion Pentavalent RV vaccination can effectively prevent rotavirus infection in infants and young children, in which the full vaccination is more effective than partial vaccination. It is recommended to strengthen the monitoring of circulating RV strains in the city, develop more targeted vaccines, and increase the RV vaccine coverage rate and full vaccination rate among infants and young children through the expansion of the national immunization program and enhancement of public education, so as to effectively reduce the incidence of infectious diarrhea in infants and young children.