• severe acute respiratory syndrome
• SARS

Since SARS (severe acute respiratory syndrome) came to Singapore, our lives have changed considerably. Fear has taken over, resulting in irrational handling and panic reactions by some, while others reacted as non-believers. It is the human response to the unknown, and the fear for the future.

In our Department of Paediatrics, as well as other departments at the National University Hospital, extensive measures have been taken (the “no risk” policy), trying to prevent further spread of the disease. Apart from extensive anti-infectious measures (gloves, masks, changing clothes, isolation procedures, etc) we divided our medical staff in two teams, who are not allowed to have any direct contact with each other, switching every two weeks to take over patient care. This would allow us, if SARS started spreading, to save at least half of our medical staff (as it seems the incubation period of SARS is within two weeks). Furthermore, parents and children avoid coming to the hospital as far as possible, resulting in empty waiting rooms and outpatient clinics. All teaching activities and research projects have been stopped for several weeks.

On the other hand, and in contrast with our colleagues in Hong Kong, we have not been able to identify any case of SARS in a child at the National University Hospital, although extensive and detailed search has become a routine procedure for all of us, especially in those children with fever and/or respiratory symptoms. Does this mean that SARS is mainly an adult and adolescent disease in Singapore? It seems to be, although no validated diagnostic test of SARS has so far become available, and diagnosis is merely based on history and clinical picture (that is, a diffuse pneumonia with fever, progressing rapidly to acute respiratory distress syndrome). Or can it be that SARS in children has a different clinical picture, including a less severe disease or an atypical presentation (that is, acute diarrhoea) or even an asymptomatic carrier state? We do not know and we will only know when a sensitive and specific diagnostic test becomes available.

There is now evidence that SARS could be the result of a novel coronavirus infection. If SARS is caused by a coronavirus, does this mean that children can be the source of SARS? Again, we do not know, but it has been shown that other coronaviruses can be detected in children.¹ However, the question remains as to why SARS affects mainly adults (at least in Singapore). Several explanations are possible. Moreover, other infections are known to cause more severe symptoms in adults, such as Varicella, Mycoplasma pneumoniae, or Chlamydia pneumoniae. Could it be that SARS is like a kind of “booster” pneumonia, needing previous contacts (and immunological priming), or does it need some co-infection (possibly Chlamydia pneumoniae), or a specific immunological condition of its host? Another reason may be that children have limited contact with the virus, as most SARS patients are infected within the hospitals (85%), and children visit hospitals less than adults, especially since the outbreak. The latter explanation however seems more unlikely, as a number of SARS patients, with children of their own, spread the disease to adult members in their family, without affecting their children.

A lot of work still needs to be done on childhood SARS, and research can only start meaningfully once an extensively validated diagnostic test becomes available. This is what we are impatiently waiting for, because once the test becomes available, our lives can hopefully change back to normal again, and fear of the unknown (that is, can children be healthy carriers of the SARS virus?) will be considerably lessened.