Flu cases reached nearly 19 million last week across the United States, with flu related deaths spiking.
After an early start to the season in places like Louisiana and Puerto Rico, the virus is nationwide. According to the CDC, as of early February the number of infections of flu B and flu A are about equal. The hospitalization rate for flu infections is 35.5 per 100,000, which is normal at this stage of the season. The percentage of influenza and pneumonia deaths is at 7.1%, falling just below the epidemic threshold of 7.2%.
The group suffering the most from this flu season is children. An increase of pediatric deaths in recent weeks brought the total to 78 this season.
What’s Behind Most of the Flu Cases?
Usually by this point in the flu season, we’re discussing which A strain of the flu is causing more cases.
The 2009 outbreak was caused by a mutated H1N1 strain known as swine flu. In 2017, an H3N2 strain of the flu caused another dangerous outbreak.
But, it’s not so simple this year. While an A strain (H1N1) has been prominent, a B strain (B/Victoria) has also been behind millions of cases. This year’s flu season began differently than most, with the B strain affecting more younger people than usual. Normally, the B strain doesn’t come around until the end of flu season.
Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases, said, “Flu B has a predilection for striking children. We’re seeing lots of children and more young adults at the present time. That’s a reflection of the dominance of flu B.”
Lynette Brammer is the leader of the CDC’s domestic influenza surveillance team. Brammer said the early and unusual dominance of flu B may be due to the lack of B viruses circulating in previous seasons.
“The Victorias (flu B) have been changing, and I think it got to the point where there wasn’t a lot of population immunity to them,” Brammer said.
It’s Possible to Catch the Flu Twice This Season
While the flu season may have started with the rare flu B, flu A has finally become the dominant strain.
Since a second flu strain is becoming dominant, there’s a much higher chance people could catch the flu twice this season. If a person caught flu B earlier in the season, they could still catch the A strain that’s circulating. Schaffner said this pattern of flu B, then flu A striking, is unusual.
Last year, two flu A strains struck back-to-back. If a person already had the first strain, the chances of them catching the second A strain is unlikely.
That’s because the two strains share some characteristics and the immune system has a memory. A person would likely already have the antibodies to defend another A strain after the first infection.
Although, the same does not pertain to flu B and flu A striking back-to-back, Schaffner said. This means a person can catch both strains in a single flu season.
According to the CDC, both the B/Victoria and the A (H1N1) strains affect children and younger people most. This adds a heightened risk for children catching the flu this year.
“Influenza B – particularly the B/Victoria that are out there – don’t tend to impact the elderly very much,” Brammer said. “But they do impact kids, particularly school-age kids.”
Although both strains typically affect younger people, anyone can catch either strain.
Scott Epperson is an epidemiologist who tracks flu activity for the CDC. “Influenza can be severe for anyone, whether it’s influenza B, influenza A,” said Epperson. He added that the number of hospitalizations remains close to what we’ve had in recent years.
Epperson also said it’s difficult to see how this flu season is going to play out with the two strains.
How Can I Stay Free of the Flu?
We are now in peak flu season, but it’s not too late to receive a flu shot. The vaccine is built to fight both the A and B strains expected to be most prominent that year.
There are also other ways to help prevent the virus. Make sure to wash your hands regularly, which is one of the best ways to protect against it, according to Dr. Molly Fleece, an assistant professor in the Division of Infectious Diseases at the University of Alabama.
Fleece said if you do catch the flu, cough or sneeze into a tissue or sleeve and don’t touch your face with unwashed hands. “Try to stay home for 24 hours after your last fever has resolved, without medication that could mask a fever.”
Do you still need to receive a flu shot? Have any other questions about this flu season? Passport Health can help. Give us a call at , or book an appointment online for more information about the virus.
Written for Passport Health by Elle Johnson. Elle Johnson is a senior multimedia journalism student at the University of South Carolina. Johnson is graduating with a bachelor’s degree in December and is a freelance writer in her free time.