Many mild infections not reported, so fatality rate was overestimated
By
Lee Hui Chieh
Health Minister Khaw Boon Wan (far left) at yesterday's update on the H1N1 flu virus in Singapore stressed the need to remain vigilant despite the downgrading of the alert level here. -- ST PHOTO: DESMOND LIM
THE reason that Singapore will soon lower its flu pandemic alert lies in a tale of an American high school - and how it signalled to the authorities that the virus may not be as severe as they had thought.
About two weeks ago, an unusually large number of about 100 students and staff members sought medical attention from the school nurse in one day, including six students and a teacher who had travelled to Mexico.
RAMPED-UP measures taken to contain the Influenza A (H1N1) virus were 'not a wasted effort', said Health Minister Khaw Boon Wan yesterday.
From today, temperature screening at schools, offices and mass public events can cease, and hospital patients can have two visitors at a time, instead of just one, amid other easing of rules.
TWELVE people, including six foreigners, have been placed under home quarantine orders since the rule to isolate those who had been to Mexico recently kicked in on Monday.
Four received their orders just yesterday while two will be allowed to venture out of their homes from Thursday.
This prompted St Francis Preparatory School in Queens, New York to survey all its 2,600 students and 220 staff members.
It found out that more than 600 people were suffering from a flu-like illness, many more than those who had actually sought help.
And most of these were likely to have caught the new Influenza A (H1N1) strain, based on test results from some of them.
Tests on viral samples from 50 of those who were ill found that 88 per cent - 43 students and one teacher - were positive for the new flu strain.
'This gives you an indication that if you had the resources to sample all the people, you might actually get a lot more patients,' said Dr Lyn James, director of the Health Ministry's communicable diseases division, who related the events to reporters yesterday.
New York's Department of Health, for example, estimated that the city has hosted more than 1,000 cases, though its official report to the World Health Organisation was less than 100 cases.
Such under-reporting of the total number of people stricken by the new flu strain could have created the impression of it being more deadly than it actually was, Dr James said.
An initial estimate of the death rate in Mexico - where all but two of the 44 deaths from the new flu strain have now occurred - put it at about 6 per cent of all those who became ill.
But experts now believe it is lower than that because many mild cases would have gone unreported, she said.
Read the full story in Thursday's edition of The Straits Times.
