[Flu Virus. Photo Credit to Freerange Stock]

The newly emerged influenza A H3N2 subclade K variant may escape this year’s vaccine in Canada, raising serious public health concerns.

H3N2 is a type of influenza A virus that causes seasonal flu, often occurring more severe in older people.

Subclade K represents a mutated version of the H3N2 influenza A strain that spreads more efficiently than earlier variants.

According to the World Health Organization (WHO), H3N2 virus has been most common in Central America, Oceania, and Northern and Western Africa.

“H3N2 can tend to be a little bit more severe; more importantly, our vaccines are not quite as good at dealing with that,” said Dr. James Dickinson, director of the Alberta Community Respiratory Viral Surveillance Program, expressing his concern.

Influenza viruses evolve through antigenic drift, a gradual accumulation of amino acid changes in surface proteins as they spread through the population.

Antonia Ho, a consultant in infectious diseases at Scotland’s University of Glasgow, further states that H3N2 had “acquired 7 new mutations over the summer,” which “means the virus is quite different to the H3N2 strain included in this year’s vaccine.”

Due to these ongoing changes, flu vaccines are updated every year to match the predicted virus types, based on the monitoring of the mutations and spread. 

 WHO experts identify the probable strains, and manufacturers produce vaccines months in advance.  

The spread of this disease is even more concerning when Dr. Wenqing Zhang, head of the World Health Organization’s Global Respiratory Threats Unit, says, “Since it emerged, it’s rapidly spreading and predominating in some countries so far in the Northern Hemisphere,”  

If protection against infection diminishes, the number of  flu cases may rise.

However, experts stress that the vaccine still provides important protection against severe illness. 

“Though seasons with poorly matched vaccines may be more severe, the important message is often ignored: even a poorly matched vaccine can reduce disease severity and outcomes,” says Seyed Moghadas, associate dean of research and graduate education and professor of computational epidemiology and vaccine science in the Faculty of Health.

This is because even if the vaccine may not be accurate, it still provides the body with an immune memory, an ability to recognize and respond faster to the virus. 

Researchers are also actively working on improving strain selection and investigating strategies such as delaying the vaccine production by three months to minimize the mismatches. 

“This is not the time to be flying blind into the respiratory virus season,” Danuta Skowronski cautions, stressing the need to be prepared against the new K variant. 

In addition to vaccination, public health authorities recommend basic prevention measures. 

Measures such as avoiding sick people, covering when coughing, and washing hands regularly can help slow the spread of germs, and prevent illnesses like flu. 

Although vaccines strengthen the body’s immune response to fight back the flu virus, it is important to recognize that simple prevention behaviors, supported by cooperation within the community, can significantly reduce the initial spread of the illness.