General practitioners in Singapore have reported that they have been treating more flu patients with some more serious cases of flu over the past week.

At Killiney Medical Clinic, for example, Dr Clarence Yeo said he noticed a 10% – 20% increase in the number of serious flu cases this month.

Dr Yik Keng Yeong on the other hand, who practises at Tan & Yik Clinic & Surgery in Bishan, has also been witnessing an increase in flu cases. One unusual case, in particular, whereby a girl visited his clinic on Thursday – had the flu – and her fever had persisted for nine days.

A Tan Tock Seng Hospital spokesman also reported an increase in the number of influenza cases from May to last month at the hospital. However, the numbers seemed to have declined this month.

In the latest weekly infectious disease bulletin issued by the Ministry of Health (MOH), the cases of acute respiratory infection seen in polyclinics here have increased from about 2,500 daily in the week of 9 July to about 3,300 daily in the week of 16 July – although, the figures are comparable to last year's.

The MOH further added that the increase in the number of seasonal influenza cases is typically observed between April and July, and from November to January – coinciding with the winter influenza seasons in the Southern and Northern hemispheres, respectively.

Mutation in dominant flu strain in Hong Kong a cause for concern

There is also an unusually long flu outbreak in Hong Kong that has killed more than 200 people since May. A top infectious disease expert has warned that a mutation in a dominant flu strain might be the reason behind the surge of cases in Hong Kong this summer.

Professor Yuen Kwok-yung, chair professor in the University of Hong Kong's microbiology department called for radical change to be made in the current public health strategy.

The dominant strain influenza A H3N2 might have mutated in a way that made vaccines used in the past two years ineffective, he added.

This "antigenic variation" in the H3N2 virus was also recently found by Danish researchers.

"The importance of this mutant to this epidemic is still in doubt. But this is still one of the possibilities contributing to this outbreak," remarked Professor Yuen.

The public, especially elderly people in nursing homes and public outpatient clinics, have been advised to obtain a two-week dosage of antiviral drug Tamiflu.

People getting flu vaccinations should also use a medication named Imiquimod, as taking it together would extend the effectiveness of the vaccine by another 12 months.

Singapore's health experts agree on increasing flu vaccination uptake

Singapore's MOH has said that there is "no evidence" of any emerging virulent strain of influenza viruses circulating in Singapore. The current common circulating influenza viruses include H3N2, H1N1 and Influenza B.

However, Mount Elizabeth Novena Specialist Centre infectious disease specialist Leong Hoe Nam felt that the development in Hong Kong is a cause for concern as the H3N2 strain is a common factor between the two countries.

"Historically, all the H3N2 mutations come from Hong Kong or South China. And they occur every few years... Everything hinges on the Hong Kong scientists to confirm or refute the presence of a new mutated virus,” Dr Leong said, adding that in cities where people live in close proximity, there could be “an unprecedented spread of a new novel virus."

Adjunct Assistant Professor Angela Chow, head of the department of clinical epidemiology at Tan Tock Seng Hospital, said the Singapore population's level of immunity is "likely to be low", given that the influenza vaccination uptake rate in the country is low.

Dr Leong also noted that the vaccine uptake is "consistently at less than 10%".

"Coupled with the fact that this (H3N2) vaccine is not particularly effective (at about 30% – 40% effectiveness), the herd immunity falls further, and more people will be prone to it," he added.

Echoing Professor Yuen's advice, Dr Leong also recommended that people who are at risk should get vaccinated including diabetics, those with kidney failure and transplants, and those taking immuno-suppressing drugs such as steroids, as well as young children and the elderly. MIMS

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