Hong Kong's flu season may become a year-round virus due to mutation, warns expert. The city's current flu season, driven by a highly transmissible mutated virus strain and exacerbated by a cold snap, could be prolonged and overlap with the winter season, according to a leading infectious disease expert. David Hui Shu-cheong, a professor of respiratory medicine at the Chinese University of Hong Kong, suggests that the flu may become perennial, similar to the situation in Singapore. This would require the acquisition of vaccines designed for both northern and southern hemispheres. Hui explains that the summer influenza peak occurred around mid-October and is now gradually receding, but the process is complicated by the onset of cooler weather. Colder temperatures naturally increase the activity of the virus, which will affect the city as temperatures are expected to drop to as low as 13 degrees later this week due to a cold front moving across the coast of Guangdong. Hui warns that when people move indoors to avoid the cold, it creates conditions that could prolong the period of transmission, particularly in places like schools and elderly homes. The dominant strain, a variant of H3N2, has undergone an 'antigenic drift', involving seven mutations that primarily affect its transmissibility. UK data estimates that the mutated strain could infect 140 people for every 100 cases, up from 120 previously. This combination of factors may prevent the epidemic from receding within the usual six-to-eight-week time frame and extend the transmission period.
