Sars less serious for children

Many children are wearing protective masks

The deadly virus Sars may have a less serious effect on young children compared with teenagers and adults, research suggests.

A team from the Chinese University of Hong Kong have come to the preliminary conclusion after studying the first 10 children with Sars who received treatment during the early phase of the epidemic in Hong Kong.

Five were teenagers, and five pre-teen. The youngest was just 18 months old.

Our preliminary observations suggest that younger children possibly develop a milder form of disease and tend to run a less aggressive clinical course

Professor Tai Fai Fok

There have been no childhood deaths from Sars up to 25 April.

The researchers found that teenage patients presented with symptoms similar to adult cases.

All the teenagers examined by the researchers had respiratory symptoms that were so severe that they had to be given oxygen.

Other symptoms included muscle ache, shivers and difficulty with breathing.

SARS WORLDWIDE

Known death tolls:

World: 812

Mainland China: 348

Hong Kong: 298

Taiwan: 84

Singapore: 32

Canada: 38

Source: WHO/local authorities

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However, younger children had much more mild symptoms such as a cough and runny nose.

And unlike the older patients, none of the younger children had shivers or muscle pains.

They also regained full health much more quickly.

Lead researcher Professor Tai Fai Fok said: "Our preliminary observations suggest that younger children possibly develop a milder form of disease and tend to run a less aggressive clinical course."

Professor Fok said the reason why younger children seemed to be less affected was unclear.

However, he said it was possible that they were protected by antibodies produced by their immune system to fight previous infections which tend to be more common in childhood.

These antibodies gradually disappear as the child gets older and remains infection-free.

"Another, more likely, explanation is that it seems that in adults much of the lung damage associated with Sars is due to the reaction of the immune system to the infection.

"In younger children this reaction may not be as vigorous as in adults because their immune system is still developing."

The research is published on the website of The Lancet medical journal.