NEW YORK (HealthDay News)—U.S. health officials have reported two human cases of “dual mutant” strains of H1N1 flu.
Unfortunately, the genetic changes appear to make the main flu antiviral, Tamiflu, less effective, noted researchers at the U.S. Centers for Disease Control and Prevention. The new analysis, published in the agency’s journal Emerging Infectious Diseases, describes the two worrisome mutations, which scientists have dubbed I223V and S247N.
The latest finding follows a report published last March in The Lancet by Hong Kong scientists that found the two mutations appeared to increase resistance to the flu treatment oseltamivir (Tamiflu).
Laboratory tests found that the mutated flu viruses were up to 16 times less sensitive to the antiviral, a smaller decrease than in some previous worrisome mutations, researchers led by Mira Patel, a senior scientist at the CDC, reported.
Still, the agency isn’t hitting the panic button right now.
“These mutated viruses retained sensitivity to other influenza medications, including a newer one, baloxavir marboxil. There are no immediate implications for changing clinical care decisions,” a CDC spokesperson told CBS News, and vaccination still offers protection against the mutated viruses.
Despite the “rapid spread of dual mutants to countries on different continents,” the CDC report added that these new flu strains remain rare for now.
Since they were first detected in a case sampled in the Canadian province of British Columbia in May 2023, 101 sequences have been submitted to the GISAID global virus database from Africa, Asia, Europe, North America and Oceania, CBS News reported.
The two cases in the United States were detected by laboratories at the Connecticut Department of Health and the University of Michigan last fall and winter.
“It is unknown how widely these mutated viruses will circulate in the upcoming season. It is important to continue monitoring the spread of these viruses and the evolution of these viruses,” the CDC spokesperson said.
Tamiflu is the most commonly prescribed flu treatment, according to the CDC. A study published in the journal Pediatrics last year found that the drug accounted for 99.8% of flu antivirals prescribed to children.
Doctors have also turned to Tamiflu to treat infected humans during an ongoing outbreak of bird flu on dairy farms this year, CBS News reported.
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2024-08-13 06:17:29
