During the severe acute respiratory syndrome (SARS) outbreak in Singapore, there was concern that SARS could spread rapidly in schools. Since SARS patients are infectious only when febrile, twice daily temperature monitoring of all schoolchildren from 6 to 16 years of age was made mandatory in Singapore during the period 30 April to 25 July 2003. All pupils were issued with a personal thermometer and trained to take their own temperatures under the supervision of teachers. Students were not allowed to attend school if their temperature reading was >37.8°C for students ⩽12 years old or >37.5°C for students >12 years old.¹ As a consequence of this policy, some otherwise asymptomatic children were turned away from school because of high temperatures.

The objectives of this study were to determine the incidence and causes for persistently high temperature readings in asymptomatic Singapore schoolchildren.

PATIENTS AND METHODS

All asymptomatic children who had (a) persistently increased temperature readings (defined as ⩾2 temperature readings above the cut-off temperatures per week for >2 consecutive weeks) and (b) no contact history with SARS and/or travel history to a country with SARS within the previous 10 days, were identified by the Ministry of Education and referred to the Ministry of Health for evaluation.

All students were seen by a panel of three doctors and a dental officer, and their temperature logs studied. All children were investigated with full blood count, peripheral blood film, C reactive protein, erythrocyte sedimentation rate, urine microscopy, and chest radiograph. Additional tests were performed if indicated. The panel of three doctors discussed each case and assigned a final diagnosis.

RESULTS

A total of 499 778 children had mandatory temperature screening in the period 30 April to 25 July 2003, of which 67 students fulfilled referral criteria. The referral rate was 1.07 children per 100 000 children-weeks of screening.

Table 1⇓ summarises the demographic characteristics and diagnoses of these students. The majority (89.5%) did not have an identifiable pathological cause and were classified as normal variants with high basal body temperatures. Of these, 12 (20.0%) had infrequent (high temperature readings <30% of all readings) while 11 (18.3%) had frequent temperature spikes (high temperature readings >70% of all readings) respectively. There was no relation between the occurrence of the temperature spike and the time of day. None of the children had SARS by clinical assessment based on the WHO case definition.² Of the six children with a pathological cause, their high temperatures settled with treatment.

All 67 children were followed up for three months and all have remained well. None required hospitalisation and none were diagnosed with a life threatening illness.

DISCUSSION

This is a large scale nationwide study involving nearly 500 000 children. To our knowledge, this is the first community study on asymptomatic children with persistently increased body temperatures. Only 9.0% of the children referred had an identifiable pathological cause. The pathologies were mild, ranging from dental to respiratory infections.

Parents whose children have persistently increased temperatures as high as 38.2°C on screening but are otherwise well with no abnormalities on medical review can be reassured that their children are healthy with no serious pathologies. We postulate that these children have high basal body temperatures secondary to decreased thermoregulatory abilities.

None of the Singapore children diagnosed with SARS were detected through school temperature screening. As was observed with temperature screening of travellers at points of entry into a country, there were only two SARS cases detected among 36 million travellers screened in Hong Kong;³ our experience with mandatory temperature monitoring in schools is that it is of low yield. However, temperature monitoring procedures have a very powerful psychological effect of reassuring parents and the public that schools are safe during a SARS outbreak. This is an important consideration which cannot be discounted. With the simplification and streamlining of procedures to reduce inconvenience to students and schools, temperature monitoring remains a useful community response in the event of an outbreak.