Hong Kong paediatrician urges parents to vaccinate children as temperatures fall

A Hong Kong paediatric expert has called on parents to arrange influenza vaccinations for their children ahead of cooler temperatures next week, warning of a double whammy of overlapping summer and winter flu seasons.

The city has recorded 29 cases of severe paediatric influenza infection this flu season, two of which were fatal.

Dr Mike Kwan Yat-wah, former president of the Asian Society for Paediatric Infectious Diseases, warned on Saturday that the city could see a longer flu season with the winter and summer waves overlapping.

“Cold weather makes it easier for viruses to spread, mainly because lower temperatures toughen up the envelope, and the respiratory droplet particles are finer and smaller in dry weather. They can travel farther and can remain suspended in the air for a longer period,” he said in a radio interview.

“Meanwhile, many different kinds of viruses are active in winter, apart from influenza, such as the respiratory syncytial virus and Covid-19 … if one contracts different kinds of viruses at the same time, the condition is more serious and may require a longer hospitalisation.”

Temperatures are expected to drop to as low as 18 degrees Celsius (64.4 Fahrenheit) on Tuesday as a cold front hits the city early next week.

Kwan said children and the elderly could develop severe symptoms such as low blood pressure or inflammation in multiple organs after catching the flu due to a “cytokine storm”.

“When our body comes into contact with these pathogens, it triggers an immune response. When such a response is excessively intense, it can suddenly trigger an inflammation of multiple organs, causing the condition to rapidly deteriorate,” he said.

Kwan said a vaccine would lower the risk of a cytokine storm by introducing a very low dose of antigens under controlled conditions to stimulate the body to generate an immune response. As a result, when people encounter this pathogen again, their bodies can mount a very rapid and appropriate immune response to control the disease, he said.

Kwan also called on residents to improve their personal hygiene, such as washing their hands before touching their eyes, nose and mouth, and to refrain from going to work or school when feeling unwell and to see a doctor immediately.

“Many parents thought a stomach ache was caused by gastrointestinal problems, but a stomach ache along with constant nausea would be a symptom of myocarditis,” he said.

If residents caught the flu and were prescribed Tamiflu – an antiviral medication to treat influenza – they must finish the whole prescription, even when the symptoms had improved, Kwan said.

He added that a second-generation antiviral drug only required one dose, which could help patients with lower drug compliance or caring difficulty.

According to the Centre for Health Protection, as of October 25, only 27.5 per cent of children aged six months to five years, 36.4 per cent of children aged six to 11 and 26.7 per cent of children aged 12 to 17 had received seasonal influenza vaccination through government vaccination programmes.