Emergence of Dual Mutant H1N1 Flu Strains in US Sparks Concern

Emergence of Dual Mutant H1N1 Flu Strains in US Sparks Concern

United States: The Centers for Disease Control and Prevention (CDC) announced on Wednesday that at least two cases of “dual mutant” strains of H1N1 influenza have been identified in US patients. These strains exhibit genetic alterations that may diminish the efficacy of the primary antiviral medication used by hospitals for flu treatment.

The CDC’s Emerging Infectious Diseases journal published an analysis this week detailing these new H1N1 strains, marked by the mutations I223V and S247N, which modify crucial surface proteins of the virus. The mutations were initially examined by scientists in Hong Kong, whose laboratory experiments, published in March, indicated an increased resistance of the H1N1 virus to the antiviral drug oseltamivir, commercially known as Tamiflu by Roche, as highlighted by ABC News.

The exact impact of these mutations on oseltamivir’s real-world effectiveness remains uncertain. Laboratory results showed that the mutated viruses were up to 16 times less responsive to the antiviral, which is a smaller reduction compared to some previous concerning mutations.

“These mutated viruses still respond to other anti-influenza medications, including a newer drug, baloxavir marboxil. There are no immediate changes required for clinical care decisions,” a CDC spokesperson stated in an email. The spokesperson also affirmed that flu vaccinations continue to provide protection against viruses carrying these mutations.

Global Spread of Dual Mutants

Despite the “swift dissemination of dual mutants across countries on different continents,” the CDC’s report indicates that these mutations are currently rare. Since their initial detection in British Columbia, Canada, in May 2023, a total of 101 sequences have been logged in the global virus database GISAID from regions including Africa, Asia, Europe, North America, and Oceania, representing less than 1% of flu virus sequences during that period.

“However, these data might not accurately reflect the actual proportion of circulating viruses due to varying surveillance and sequencing strategies in different countries,” the authors noted, as per the reports by ABC News.

The two U.S. cases were identified by laboratories at the Connecticut Department of Health and the University of Michigan during the past fall and winter seasons.

“It remains unknown how extensively these mutated viruses will spread in the upcoming season. Continuous monitoring of their spread and evolution is crucial,” the CDC spokesperson emphasized.

Predominance of Oseltamivir

The CDC has had a standing for monitoring for potential flu virus mutations as a foundation for resistance to oseltamivir, the most prescribed flu treatment to date. A study conducted last year to determine oseltamivir peak plasma concentrations found that oseltamivir was responsible for 99. It also reported that it sold 8 percent of flu antiviral drugs given to children.

According to CDC, providers should initiate oseltamivir as early as possible in severe influenza cases or in any patient admitted with the flu or those with comorbidity. However, oseltamivir, also known as Tamiflu has been in used to treat affected humans that fall prey to the ongoing H5N1 bird flue outbreak in dairy farms this year.

This is not a new phenomenon that has not been witnessed in other countries before. Authorities responsible for health have previously monitored similar threats to the efficacy of treatments for the flu. For example, prior to being displaced by the H1N1 strain involved in 2009, pandemic flu, such as another H1N1 resistant to oseltamivir, emerged in Europe and Japan in 2007 and 2008. This strain carried the H275Y mutation and was up to thousands of times less sensitive to oseltamivir in laboratory tests than other seasonal viruses, as per ABC.

In general, the discovery of such dual mutants of H1N1 infection may become a future problem. However, constant monitoring of H1N1 infection and continuous research on top of it MUST continue in order to prevent a subsequent outbreak.

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