Implementation of SARS-CoV2 Monitoring and Screening test using RT-PCR in Okinawa prefecture, Japan, 2021

Abstract

Objectives: To provide evidence on RT-PCR testing in order to implement effective RT-PCR testing by demonstrating that the positivity rates of monitoring and screening tests vary depending on the subject and the level of contact.

Design: Retrospective epidemiological analysis

Setting: RT-PCR monitoring projects and screening tests in School PCR Projects conducted in Okinawa Prefecture.

Participants: Workers in high-risk work areas, local residents, and airline passengers to/from Okinawa prefecture. School-aged children categorized into close contacts and contacts. RT-PCR monitoring tests and screening tests are 656265 and 26000, respectively.

Main outcome measures: Percent positives in RT-PCR monitoring tests and a proportion of the positives in close contacts among the positives in all contacts in screening tests in School PCR Projects.

Results: The highest and second-highest positivity rates in RT-PCR monitoring tests were 3.65% (95%Confidence Interval: 3.25-4.10%) in Free inspection service for restaurant employee project 2.67% (95%CI: 2.60-2.73%) in Inexpensive testing subsidy program, respectively. The order of the highest percentage of the positives in close contacts among the positive in all contacts by school type is as follows: 26.0% (95%CI: 16.6-37.2%) in after school children’s clubs, 17.0% (95%CI: 7.7-30.8%) in high school, 16.1% (95%CI: 7.6-28.3%) in elementary school, 15.2% (95%CI: 5.1-31.9%) in junior high school, excluding special support schools, nursery schools, and kindergarten, due to data scarcity.

Conclusion:  

Increasing access to testing for restaurant employees and residents who wish to be tested will contribute to the efficient detection of infected individuals. Additionally, expanding these testing spots can reduce the burden on medical institutions due to the visits to the emergency room for testing. Secondary infection risks are much higher at after-school children's clubs, whereas those at elementary school remain low even after summer vacations. To prepare for a future outbreak, infection control measures should be placed on this school type.