Objective: An epidemic of severe acute respiratory syndrome (SARS) hit Beijing, China, between March and July 2003 with an attack rate of 1.9 per 10 thousand. (2,521 cases). To control the epidemic of SARS, a total of 30,173 residents were quarantined either in their residence or in quarantine sites. In order to understand the personal need of being quarantined and to estimate the risk of developing SARS during the quarantine period, a survey on the quarantined residents of Haidian District, Beijing, China was carried out.
Methods: 33 precincts in Haidian District divided into five groups (7 in north, 6 in south, 7 in west, 6 in east and 7 in central of Haidian District) according to the location of the precincts were involved. The director of Center of Disease Control and Prevention of Haidian District was asked to select 1 precinct from each group according to the workload of the precinct quarantine officers. From those 5 precincts we obtained lists of all quarantined persons from the precinct quarantine officers. All quarantinees were asked to complete a self-administered questionnaire. The SARS patients were diagnosed and verified according to the diagnosis criteria released by Chinese Ministry of Health which was equivalent to the SARS 'probable case' definition of WHO. All SARS cases had been reported to the relative authorities.
Results: By May 23, 2003, 5,186 persons had been quarantined in Haidian district, accounting for 0.23% of all residents. 1,028 of sampled quarantined residents completed the questionnaire. Of those who completed the questionnaire, 2.3% (95% CI: 1.5% - 3.5%) developed SARS while under quarantine. The median quarantine period was 14 days (range 1 day to 28 days). 61% of the quarantinees had a direct contact history with SARS patients, and all secondary SARS patients developed through contact to these quarantinees. The remaining 39% quarantinees who did not have a direct contact history with SARS patients had not developed SARS during the period under quarantine. 37% of the quarantees had direct contact during original patients' symptomatic period with an AR of 6.3%. Persons who looked after the illed SARS patient(s) during their symptomatic period, had an highest attack rate of 31% (95% CI: 20% - 44%). 63% (95% CI: 60% - 66%) of the total quarantined persons did not have direct contact with a SARS patient during his/her symptomatic period, with an attack rate of 0% (95% CI: 0% - 0.73%).
Conclusion: Only those persons having direct contact with ill SARS patients need to be under quarantine. The overall cost for quarantine on SARS prevention could be reduced by as much as 63% if the quarantine program was limited to this group. No evidence was found that SARS patient was infective during the incubation period.