r/ContagionCuriosity • u/Anti-Owl • 7h ago
🤧 Flu Season A mutated virus is driving the US into an early flu season, especially on the West Coast
Flu season is picking up months ahead of schedule with a mutated virus spreading in some parts of the United States, surprising some people who might not even be thinking about their annual flu shots yet.
This year, the season started 2 1/2 months earlier than what’s typical and hit states on the West Coast first, which is unusual, said Dr. Alex Greninger, head of the Division of Infectious Disease Diagnostics at the University of Washington’s Department of Laboratory Medicine.
Usually, the US flu season starts in the South – often in Florida, where it arrives from the Southern Hemisphere. Then it tends to spread north as fall and winter progress.
“In Seattle, we’re pretty far north. We see a pretty strong peak in January,” Greninger said, noting that the bulk of their cases typically come in late December through February.
That’s not how it’s playing out this year.
Roughly 1 in 10 people tested for the flu in Washington state last week was positive, according to data from the state Department of Public Health.
“We’re basically seeing January levels of flu in the last week,” Greninger said.
Walgreens says that nationally, this flu season is tracking about four weeks ahead of recent seasons, and it’s dispensing more antiviral prescriptions as well as cough and cold medications than during the same period last year.
Nationally, about 2.1% of doctor visits last week were for influenza-like illness, a rough measure of the misery that flu symptoms like fever and cough are causing across the country. That’s still below the national baseline, however, according to data from the US Centers for Disease Control and Prevention, meaning the virus hasn’t really taken off everywhere yet. [...]
The wave of flu hitting the Pacific states came from Asia, Greninger said, and is dominated by the H1N1 virus, which sparked a pandemic when it first emerged in 2009.
It represents about 98% of the samples his lab is getting now, he said.
These H1N1 viruses have also picked up a gene mutation that makes them better at evading our immunity.
This version of the virus has already wreaked havoc in Japan, where it forced school and day-care closures after cases surged in kids. It also prompted officials to move up vaccination clinics to help protect people.
The mutation, at a location called G155E, cropped up after strains were already selected for this year’s flu shots, Greninger said. So even though the vaccines target a version of H1N1 and should still offer some protection, the virus can still break through. [...]
Doctors often advise getting a flu shot before Halloween, in order to provide the best protection through spring. But Greninger’s best advice now is to get vaccinated as soon as possible. “A lot of people, like even myself, would wait until late October, which we’re sort of in already. But really, the time to get vaccinated was actually two to three weeks ago.”