Flu Virus Mutation May Weaken Effectiveness Of Current Vaccine

Chuck Bednar for redOrbit.com – Your Universe Online
The influenza virus circulating throughout the US this year has mutated, and as a result, the currently-available vaccine is less effective in combating the illness, the Centers for Disease Control and Prevention (CDC) said in an advisory to doctors issued on Wednesday.
According to Maggie Fox of NBC News, the majority of cases this year are being caused by the H3N2 strain, which is one of the influenza types the current vaccine is designed to protect against. However, health care officials said that this H3N2 strain has mutated so that less than half of the cases match the version included in the flu shot.
Specifically, the CDC reported that influenza viral characterization data has indicated that 48 percent of the H3N2 viruses collected and analyzed from October 1 through November 22 were “antigenically ‘like’ the 2014-2015 influenza A (H3N2) vaccine component,” and that 52 percent had “drifted” or mutated from the vaccine virus.
“In past seasons during which predominant circulating influenza viruses have been antigenically drifted, decreased vaccine effectiveness has been observed,” the agency said, noting that vaccination has still been found to “provide some protection against drifted viruses.” Getting vaccinated could still “reduce the likelihood of severe outcomes such as hospitalization and death” and “will offer protection against circulating influenza strains that have not undergone significant antigenic drift from the vaccine viruses (such as influenza A (H1N1) and B viruses),” the CDC added.
However, as a result of the drifted influenza A (H3N2) viruses, the health advisory suggested the use of neuraminidase inhibitor antiviral medications alongside flu shots to help treat and prevent the illness. Specifically, they mentioned the prescription antiviral medications oseltamivir (Tamiflu) and zanamivir (Relenza), as their use has previously been linked with reducing the risk of severe influenza-related health problems.
The CDC said that these antivirals should be used as soon after the onset of flu-like symptoms as possible. Officials with the disease-prevention center noted that clinical trials and observational data have linked early antiviral treatment to a shortened duration of fever and other symptoms, a reduced chance of pneumonia or other complications in both children and adults, and a decreased risk of death in hospitalized influenza patients.
“The flu is bad, and you want to do anything you can to prevent getting it and to prevent giving it to other people. The vaccine isn’t perfect, but it’s the best protection we have for prevention,” New York City-based pediatrician Dr. Lisa Thebner told CNN.com’s Debra Goldschmidt. When asked if people should be concerned, the doctor added that they “should always be concerned about the flu.”
While Goldschmidt said that the latest flu outbreak data from the CDC indicates that flu activity in the US is currently low, the agency said it had “increased slightly” in most parts of the country as of November 22. A total of 12,337 people were hospitalized with flu-related illness and 149 children died during the 2012-2013 flu season. Ninety percent of those children had not been vaccinated, according to the CNN.com reporter.
In January of this year, Lawrence LeBlond reported on the 2013-2014 flu season. During that time, H1N1 was the dominant strain. He also reported that H3N2 was the dominant strain during the 2012-2013 flu season.
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