Centre for Health Protection: Hong Kong has entered flu season, and COVID-19 activity is trending upward.

Dr. Ō Ka-wing of the Communicable Disease Branch of the Centre for Health Protection said that the level of seasonal influenza activity has continued to rise over the past few weeks. The latest data show that two indicators—namely, the influenza virus positivity rate from laboratory surveillance and the influenza-related hospitalization rate in public hospitals—have both exceeded the baseline levels, so Hong Kong has entered the influenza season.

He said that figures from last week showed the influenza positivity rate was 6.69%, exceeding the baseline level of 4.94%. Among the positive samples, about 60% were influenza A(H3), followed by influenza A(H1), accounting for around 20%, and influenza B also accounted for around 20%. The influenza-related hospitalization rate in public hospitals is also on an upward trend. It rose from the end of May and reached 0.38 cases per 10,000 people last week, exceeding the baseline level of 0.27 cases per 10,000 people.

In addition, the number of influenza outbreak cases in residential care homes and schools has increased. A total of 46 outbreak cases were recorded last week, higher than the average of 24 outbreak cases per week in the previous four weeks. Among the influenza outbreak cases, around 70% occurred in schools, and of those, 70% occurred in primary schools.

As for severe and fatal cases, the number of severe adult cases rose from an average of 8.6 cases per week in May to 23 cases last week. Of these, 70% were elderly people, and about 60% had not received this season’s influenza vaccine. This week, so far there have been 2 severe pediatric cases, including 1 influenza A(H1) case and 1 influenza A(H3) case. Up to now this year, there have been 10 severe pediatric cases, with no fatalities reported so far.

Ō said that Hong Kong has entered the influenza season. At present, influenza A(H3) is the main circulating strain. Elderly people, young children, and people with chronic illnesses are high-risk groups. It is expected that influenza activity will further increase over the coming weeks. Accordingly, the relevant hospitalization figures, influenza outbreaks in residential care homes and schools, and severe cases may also increase, and the Centre will closely monitor the situation.

As for COVID-19, since May this year, overall COVID-19 activity has continued to trend upward. Among respiratory specimens collected by the Public Health Laboratory Services, the positivity rate for COVID-19 testing increased from below 1% per week before the end of May to 6% last week. The virus strains currently most prevalent in the community are still the JN.1 descendant lineages that have been circulating locally over the past one and a half years, including NB.1.8.1 and XFG. Laboratory surveillance has so far not found an unusual increase in the proportion of other variant virus strains.

Regarding severe COVID-19 cases, from May to June 27, the Centre recorded a total of 23 severe or fatal adult cases, including 2 fatal cases. During the same period, 2 severe pediatric cases were recorded, and both children had not received the initial doses of the COVID-19 vaccine. In addition, the number of reported COVID-19 outbreak cases in residential care homes and schools in recent days has also increased—from an average of 1 outbreak per week from May to mid-June, to 6 outbreaks last week. In recent weeks, the outbreaks have mainly occurred in residential care homes.