Post-holiday flu surge warning

Cheng Wong

Hong Kong travelers returning from overseas after the Christmas holiday may bring seasonal flu viruses back to the SAR, potentially leading to a mid-January flu peak, warns respiratory medicine expert David Hui Shu-cheong.

However, he said the city is unlikely to face a major Covid-19 outbreak, suggesting that the SAR will not undergo a simultaneous surge of both viruses.

Hui, the chairman of the Department of Medicine and Therapeutics at Chinese University of Hong Kong, said on a TV program yesterday that children below two and seniors older than 65 remain at higher risk.

"According to the latest surveillance data from the Centre for Health Protection, the average consultation rates for flu-like illness among both sentinel general outpatient and private medical practitioner clinics have increased compared to the previous week," Hui said.

"This indicates a high likelihood that flu cases will continue to rise."

He said the current positive 1.35 percent was below the 4.94 percent baseline threshold, but suggested it will hit that level within a few weeks.

The threshold, set by the CHP, is based on data from the past years' non-seasonal periods, allowing the authority to assess the local situation and determine when the city enters the flu season.

Whether it will last up to seven months like last winter's flu peak, Hui said, remains to be seen.

As H1N1 has been circulating in the city throughout 2024, "a significant outbreak is unlikely to happen," he said. "But we are not sure whether it will be followed by a surge in H3N2, which could prolong the flu season since the community lacks immunity to H3N2."

Given a five-percent increase in the city's flu vaccination rate compared to the same period last year, the overall situation should not be worse than before, Hui said.

He added that 31 severe pediatric flu cases had been recorded in the first seven months of 2024, and that children aged two to five are 6.4 times more likely to experience complications or death from infection compared to their vaccinated peers. He urged parents to be aware and vaccinate their children promptly.

Hong Kong currently provides a quadrivalent flu vaccine designed to protect against four different flu viruses - H1N1, H3N2 and two influenza B viruses.

Hui also observed that fewer people are wearing face masks this winter, so he urged people to step up protective measures.

"When I shop in the mall, I estimate that less than 20 percent of people are wearing masks, compared to about 40 to 50 percent in previous years."

Wearing masks properly and maintaining strict hand hygiene at all times are effective in preventing respiratory infections, he said.

Hui urged high-risk groups such as the elderly and those suffering chronic diseases to get Covid shots to make up for their weaker immune system response.

"Even after vaccination, antibodies do not last long and may drop to very low levels after four months," he said. "Additionally, the T-cell response, which helps prevent severe cases and death, will also decline over time in these high-risk groups."

As of November 19, JN 1 Covid-19 vaccines are offered to eligible persons 12 and above. XBB Covid vaccines are available for those aged 6 months to 11 years.

cheng.wong@singtaonewscorp.com