Assessment of border control measures and community containment measures used in Japan during the early stages of Pandemic (H1N1) 2009

Abstract

Background: In the early stages of Pandemic (H1N1) 2009, border control measures were taken by quarantine stations to block the entry of infected individuals into Japan and community containment measures were implemented to prevent the spreading. The objectives of this study were to describe these measures and the characteristics of infected individuals, and to assess the measures' effectiveness.

Methodology/principal findings: Border control and community containment measures implemented from April to June (Period I: April 28-May 21, Period II: May 22-June 18) 2009 were described. Number of individuals identified and disease characteristics were analyzed. For entry screening, a health declaration form and an infrared thermoscanner were used to detect symptomatic passengers. Passengers indicated for the rapid influenza test underwent the test followed by RT-PCR. Patients positive for H1N1 were isolated, and close contacts were quarantined. Entry cards were handed out to all asymptomatic passengers informing them about how to contact a health center in case they developed symptoms. Nine individuals were identified by entry screening and 1 during quarantine to have Pandemic (H1N1) 2009. Health monitoring by health centers was performed in period I for passengers arriving from affected countries and in period II for those who had come into contact with the individuals identified by entry screening. Health monitoring identified 3 infected individuals among 129,546 in Period I and 5 among 746 in Period II. Enhanced surveillance, which included mandatory reporting of details of the infected individuals, identified 812 individuals, 141 (18%) of whom had a history of international travel. Twenty-four of these 141 passengers picked up by enhanced surveillance had been developing symptoms on entry and were missed at screening.

Conclusion/significance: Symptomatic passengers were detected by the various entry screening measures put in place. Enhanced surveillance provided data for the improvement of public health measures in future pandemics.

Figure 1. Flow of each measure to identify infected individuals in Japan during the period April 28–June 18 and the number of individuals infected with Pandemic (H1N1) 2009 with international travel histories within 7 days of onset (n = 151).

Note: n is the number of individuals identified with Pandemic (H1N1) 2009 by each measure: 10 for Border Control Measures at Narita International Airport (4 from entry screening and 1 from quarantine in period I, 5 from entry screening in period II); 141 for Community Containment Measures (3 from health monitoring in period I, 5 from health monitoring and 133 from mandatory reporting in period II). The 24 missed cases are not shown as it is not known whether they were identified by health monitoring or enhanced surveillance. *Affected countries: Mexico, mainland U.S., Canada. **MHLW: Ministry of Health, Labour and Welfare of Japan.