Hong Kong might have grown accustomed to treating seasonal influenza as a temporary inconvenience rather than a public health menace as the virus comes and goes every year. But with a lower vaccination uptake and a raging and longer-than-expected summer outbreak this year, the same business-as-usual response is hardly the right defence. Members of the public, especially high-risk groups, should waste no time coming forward for the jabs as local health authorities put the city on alert.

Officials warned that the flu season could last longer than last year’s 18 weeks, noting that 16 weeks into the current outbreak, there were still no signs of it abating. In the four weeks to October 17, 10 to 12 per cent of respiratory samples tested positive for the virus, nearly double the baseline level. Hospitalisation rates have reached 0.4 to 0.7 per 10,000 people, two to three times the benchmark. The prolonged season is linked to a shift in dominant virus strains, according to the Centre for Health Protection.

The human cost is already evident. Some 472 flu outbreaks have been recorded in schools since September, affecting more than 2,800 persons. At least 25 severe paediatric cases requiring intensive care have been reported since the June outbreak, including an unvaccinated 12-year-old girl who died on October 20. In August, a seven-year-old boy who had received a 2025-26 flu jab and had been in good health also died of complications related to influenza A. At least 889 severe influenza cases among all ages have been reported during the season so far, including 596 deaths.

These are not abstract statistics. They underline the threats to the community and signal a public health system under sustained pressure. “The flu outbreak this year is actually not milder than last year’s … I hope everyone, the public, pays attention and does not underestimate the flu as being a very simple disease,” said Edwin Tsui Lok-kin, the Centre for Health Protection controller.

Given the effectiveness and availability of flu jabs, many of these infections and deaths could have been avoided. The authorities urged people to be on alert as early as June following an increase in flu activities in May. While more than 900,000 doses have been administered since the roll-out of the current programme last month, the coverage remains 10 per cent short of that from the same period last year. Vaccination rates fell across all age groups, with the 2-to-5 and 6-to-11 age brackets seeing a decline of nearly 5 percentage points, while community elderly vaccination rates fell by 1.8 percentage points. The situation is worrying.

According to the World Health Organization, there are around a billion cases of seasonal influenza annually, including 3 to 5 million cases of severe illness. While most people recover without treatment, the disease causes 290,000 to 650,000 respiratory deaths annually.

This is why there is no room for complacency and slackness when it comes to controlling infectious diseases. Experts say pregnant women, children under 5 years of age, older people and individuals with chronic medical conditions are more vulnerable as they are at greater risk of complications when infected.

The city was already warned last year of a prolonged summer flu outbreak that might overlap with the winter flu season. As the public health watchdog rightly noted, the community should not mistake flu for a mild disease. A seasonal outbreak that begins earlier, lasts longer and shifts between strains leaves more people exposed.

That makes timely vaccination all the more important. Official analyses showed that the rate of severe complications or death among unvaccinated children following influenza infection was about five times higher than that among vaccinated children. Among unvaccinated residents aged 65 years or older living in residential care homes for the elderly, the rate of severe complications was about four times higher than that among vaccinated residents.

Hong Kong is fortunate to have the medical infrastructure and expertise needed to curb the flu outbreak. What it lacks are individual will, a sense of urgency and actions for vaccination. The longer the delay, the greater the impact and losses for the community as a whole.