Estimating rotavirus vaccine effectiveness in Japan using a screening method

Area of Science:

• Pediatrics
• Infectious Diseases
• Vaccinology

Background:

• Rotavirus gastroenteritis presents a substantial global health challenge.
• Rotavirus vaccines have been available in Japan since 2011, but their coverage and effectiveness remain unevaluated.
• Lack of a national vaccination registry complicates coverage assessment.

Purpose of the Study:

• To evaluate rotavirus vaccine coverage and effectiveness in Japan.
• To assess the impact of financial support on vaccination uptake.
• To provide the first comprehensive analysis since vaccine introduction.

Main Methods:

• Estimating vaccination coverage using manufacturer supply, financial support data, and target population size.
• Identifying rotavirus gastroenteritis cases through medical record review in six major hospitals.
• Investigating patient vaccination status via medical records and guardian interviews.
• Determining vaccine effectiveness using a screening method.

Main Results:

• Vaccination coverage showed an upward trend and was doubled in areas with subsidized vaccination fees.
• In the 2012/13 season, Saga Prefecture reported 14.9% vaccination coverage.
• Vaccine effectiveness was estimated at 69.5% for clinically diagnosed cases and 88.8% for hospitalized cases.

Conclusions:

• Rotavirus vaccination coverage is increasing in Japan, influenced by financial incentives.
• The rotavirus vaccine exhibits high effectiveness in preventing gastroenteritis.
• This study provides crucial data on vaccine impact in Japan, informing public health strategies.