A paediatrician is reminding parents of young children to get them vaccinated against flu, saying population immunity against the virus decreased during the Covid pandemic.

Speaking on RTHK's Hong Kong Today programme, Professor Patrick Ip, from the Department of Paediatrics at the University of Hong Kong, described the situation in Hong Kong as challenging, saying there had already been two flu peaks this year. He said Covid infection control measures had had a knock-on effect on immunity.

"Probably because of all those infection control measures earlier, the immunity of our children and our population have been quite different. So now when we are returning to schools, we are actually facing quite a number of outbreaks," Ip said.

Ip also said that the flu cases seen in youngsters tended to be more serious.

"We probably realise that in the past, before Covid, usually when children got an influenza infection, it would be relatively mild and with symptoms for roughly around three-to-four days - and most of those admissions to hospitals would only require a short stay, " he said.

"But during the post-Covid period, what we are facing is children with a little bit more severe influenza than before. Many of them need to stay in hospital for a much longer period, maybe up to one week, with more severe symptoms. Sometimes even more complications."

Ip said these complications were particularly worse among children who had never been vaccinated, leaving them at risk of more severe complications like pneumonia or even encephalopathy affecting their brain.

Ip said the new flu vaccine would be available from the end of this month.