Effectiveness of Lanzhou lamb rotavirus vaccine in preventing gastroenteritis among children younger than 5 years of age.

BACKGROUND

Lanzhou Lamb rotavirus (LLR) vaccine was licensed in China in 2000. It was the only vaccine available in private market before 2018. However, the data about the post-marketing effectiveness is very limited. To assess the vaccine effectiveness (VE), we conducted a case-control study based on the hospital surveillance system in Beijing from 2015 to 2017.

METHODS

Seven hospitals located in seven districts in Beijing, from October 1, 2015, to March 31, 2017, were included. The VE of LLR vaccine was assessed in laboratory-confirmed rotavirus infection among children younger than five years old through a case-control design, using rotavirus-negative cases as controls. LLR vaccination was documented from a vaccination registry. VE was estimated adjusting for age group, gender, study site, the month of illness onset and interval days between illness onset to sampling through a logistic regression model.

RESULTS

A total of 598 cases and 1766 controls were included in this study. The vaccine average coverage rate during 2015-2017 among children younger than five years old was 10.8% in Beijing. The adjusted VE for LLR vaccine of 1 dose versus 0 dose was 34.9% (95%CI, 5.3-55.3). We also obtained the adjusted VE of 87.7% (95%CI, 32.7-97.8) for patients with the severity score ≥11, 36.2% (95%CI, 4.7-57.3) for children of 2-35 months age group and 40.8% (95%CI, 7.8-61.9) against G9 rotavirus infection. Vaccinated cases were less likely to have watery stool (OR = 0.42) and have diarrhea longer than 5 days (OR = 0.47) than unvaccinated cases.

DISCUSSION

LLR vaccine conferred protection against rotavirus disease. Children who were vaccinated presented with less severe clinical manifestations. An immunization schedule of receiving all three doses in the first year should be preferred.