Can Flu Vaccine Protect Against H3N2 Virus? A Virologist Explains

H3N2 is not a new virus. It has been around since 1968. Why is it surging in India now? Dr Shahid Jameel explains.

Dr Shahid Jameel Decodes H3N2 virus, flu vaccines.

(Photo: FIT)

Video Editor: Pawan Kumar

The H3N2 flu virus is not a new one, in fact, it's been around since 1968. Why then, is India seeing a surge in cases of severe flu driven by this variant? Can seasonal flu vaccines help protect you from H3N2 too?

FIT speaks to renowned virologist, Dr Shahid Jameel to find out.

Why is H3N2 Spreading Now?

"People are worried because the H3N2 virus is a particularly troublesome virus when it comes to protection from the available vaccine, and protection from immunity that has developed simply due to exposure to other viruses," explains Dr Shahid Jameel.

But to understand this, let's take a closer look at the epidemiology of influenza virus.

Influenza viruses come in four different types A, B, C, D, says Dr Jameel.

It's mainly the A and B viruses that infect humans and cause disease, and within these there are multiple lineages.

"The H3N2 lineage was first seen in the 1968 pandemic of flu. This particular virus, the H3N2 has some genes that have come also from swine influenza too. So what people are calling this is the H3N2V or H3N2 variant virus."

Dr Shahid Jameel, Virologist

Why, then, are we seeing a surge in cases now?

This is because, "flu cases go up in cycles," says Dr Jameel. So the surge isn't necessarily unusual.

"For example, in India, using the latest data available from NCDC and also from WHO, one finds that 2015 was a big year for flu, and then it went down, and then 2019 again was a big year. 2022 was another big year."

Dr Shahid Jameel, Virologist

"So, it goes in three or four year cycles," he adds.

Can Flu Vaccines Help Prevent H3N2?

Flu vaccines have been around for decades now, but, Dr Jameel says, "historically, if you see flu vaccines haven't been that popular in India."

"Usually the reaction is how many vaccines will I take?" he says.

"There's this miscount section that vaccines protect against infection. Most vaccines don't. They protect against disease."

Dr Shahid Jameel, Virologist

Dr Jameel says, "yes, go ahead and take a vaccine. Don't take a chance."

However, he adds, "making the vaccine mandatory for everyone is not going to be a good policy decision."

"It's not a cheap vaccine. It'll cost anywhere from about ₹800 to ₹2000 depending upon which vaccine you take."

Dr Shahid Jameel, Virologist

"But above all, if you're in closed spaces, public transport, crowded places, wear a mask. It's an inexpensive way to protect yourself from infection," he adds.