Varicella outbreak at nursery school under routine immunization in Japan in 2017 and 2018 and vaccine effectiveness.

Background: In Japan, routine administration to one-year-old children of two-dose immunization for varicella was introduced in October 2014. Object The object of this study was to report outbreaks of varicella under routine immunization at a nursery school and in its surrounding area using data of surrounding areas from the (Nursery) School Absenteeism Surveillance System. Then, we measured the effectiveness of routine two-dose immunization for varicella to onset.

Susceptibility of nursery teachers to measles, rubella, varicella and mumps in Japan.

Background: A guideline published in 2018 by the Ministry of Health, Labour and Welfare stipulated confirmation of the vaccine history of nursery staff members.

Object: This study was conducted to elucidate nursery teachers' vaccine and infection histories for measles, mumps, rubella, and varicella through survey responses.

Method: After sending questionnaires through the mail to 5000 nursery teachers in November 2022, we received responses through December 2022.

Nursery school absenteeism surveillance system and infection control measures in nursery schools.

Introduction: The Nursery School Absenteeism Surveillance System (NSASSy), which includes 40% of all nursery schools in Japan, has a degree of effectiveness that is difficult to prove: nursery schools and areas without NSASSy cannot be evaluated for their incidence of infectious diseases as precisely as those with NSASSy. Instead, we examine nursery school countermeasures against infectious diseases by considering the endogeneity bias of NSASSy.

Method: After sending questionnaires to 500 Tokyo metropolitan and nearby nursery schools in November 2022, we received their responses through the end of 2022.