Flu Cases are Spiking and Cases Will Likely Continue to Rise

The flu arrived as expected, but infections are increasing more quickly than in past years.

During the past week alone, more than 19,000 people were hospitalized with influenza.

That number jumped by roughly 10,000 compared to the week before, according to the Centers for Disease Control and Prevention.

So far this season, an estimated 7.5 million people have caught the flu, and more than 3,100 deaths have been linked to the illness.

Health experts say the recent spike appears to be tied to a newer strain of influenza A (H3N2), known as subclade K. The strain first surfaced in Australia over the summer and has since spread widely.

Andrew Pekosz, a virologist at Johns Hopkins University, said that once this strain shows up in an area, a sharp increase in flu cases tends to follow.

New York has been hit particularly hard.

State health officials reported more than 71,000 cases last week, the highest weekly total ever recorded there.

High flu activity is also being reported in other parts of the country, especially across the Midwest, Northeast, and South.

Pekosz added that much of the national flu map is mostly red, meaning that infection levels are high and likely to keep rising in the coming weeks.

What’s Behind the Surge?

According to virologist Florian Krammer, there is no clear evidence that this new strain causes more severe illness or spreads more easily than past versions.

However, the virus is now better at slipping past existing immune defenses.

There have also been questions about how well this season’s flu vaccine matches the new strain. The vaccine formula was finalized last February, before the new strain appeared.

Even so, Krammer emphasized that the flu shot remains the best tool available for protection, even if it’s not a perfect match.

Early data from the U.K., where flu activity surged sooner than usual, suggests the vaccine is about 30 to 40 percent effective at preventing severe illness that leads to hospitalization.

Vaccines only work for people who get them, and in the U.S., just 42 percent of adults have received a flu shot so far this season.

That leaves a large portion of the population exposed.

Lisa Grohskopf, a medical officer with the CDC, said it is still worth getting vaccinated if you have not already done so.

She also pointed out other precautions can help lower your risk, such as wearing a mask on public transit or in crowded indoor spaces and healthcare settings.

Keeping some distance from others, especially if someone close to you is sick, can also reduce the chances of you catching the virus.

Grohskopf added that effective treatments are available if you do get infected, particularly when started within the first 48 hours. She emphasized the flu isn’t something you should take lightly.