An infectious disease expert on Saturday warned that Hong Kong could be hit by a double whammy in which its peak influenza seasons are dominated by two flu virus strains - one after another this year.

Speaking on a Commercial Radio programme, Ivan Hung, who's also a professor at the University of Hong Kong, said that influenza virus infections have rebounded to a relatively high level recently, as residents have low immunity to influenza after three years of the pandemic.

He said while the peak flu season dominated by the A subtype H3 virus strain ended last October, infections have continued this year and the SAR also has to contend with a peak season dominated by the A subtype H1 flu virus strain.

"In January we have already had the influenza peak season for the subtype H3 virus, and then starting in April and May, we had the peak season that's dominated by the subtype H1 virus.

“While the H1 virus-led inflections might ease from June and July, there's a chance that we might see the H3 virus making a comeback to form another small peak season from August and September,” he explained.

“But I think overall, the H3 virus-dominated peak season might be less serious compared with the one seen last year,” he added.

The infectious disease expert again called on parents to take their children to get a flu vaccine shot prior to the summer vacation, as there were many serious cases of children infected by the subtype H1 virus.

He also noted that the city’s Scientific Committee on Vaccine Preventable Diseases had recommended that the Department of Health increase the procurement of the nasal vaccine to raise vaccination rates, as young children were more willing to receive the nasal vaccine.

Separately, Hung predicted that the new Covid variant - KP.2 strain - that was discovered in the city’s sewage system, will replace the current prevalent variant - JN.1 - as the dominant Covid strain. But he said the new variant will not cause severe cases.