Hong Kong could face a “relatively severe” summer influenza outbreak this year, health authorities have warned, as the percentage of positive cases has already exceeded the peak of the previous season and flu activity continues to rise.
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The Centre for Health Protection said on Thursday evening that at least 451 outbreaks had been reported in schools so far since the start of the school year in September.
Among them, 43 cases occurred in kindergartens or childcare centres, 244 were recorded in primary schools and 164 in secondary schools.
The latest surveillance data showed that 12.02 per cent of respiratory specimens tested positive for seasonal flu viruses during the week of October 5 to October 11, up from 9.70 per cent the previous week. The figure also surpassed the winter flu season’s peak of 10.54 per cent recorded earlier this year.
Edwin Tsui Lok-kin, controller of the Centre for Health Protection, said that the emergence of a summer influenza season in September was uncommon, as it typically occurred between July and August and lasted for six to 18 weeks.
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He added that the protective immunity generated by the last seasonal influenza vaccination would have waned, as most people received their jabs more than nine months ago.
“Coupled with the fact that the new seasonal influenza vaccines for this season have only recently become available on the market and some people have not yet received this year’s vaccine, this year’s summer influenza outbreak is expected to be relatively severe,” he warned.