What might be an emerging strain of flu resistant to the anti-viral drug Tamiflu could affect plans to respond to a bigger flu pandemic, one flu expert said.
In its last national flu report for the week ending Dec. 20, the Centers for Disease Control and Prevention noted that 64 of 65 samples of the influenza A H1N1 strain were resistant to oseltamivir, marketed as Tamiflu.
Dr. James A. Wilde of Medical College of Georgia, who sits on a statewide planning committee for pandemic flu, said he was concerned but not alarmed at this early evidence, which both the CDC and Dr. Wilde noted is from a very small number of samples.
Still, it reminded Dr. Wilde of a similar antiviral resistance that cropped up suddenly in another strain of influenza A, which became resistant to the adamantane antivirals.
"This was almost overnight," Dr. Wilde said. "The year before we had very low levels and all of a sudden we skyrocketed to 90 percent (resistant)."
At the end of last year's flu season, 10.9 percent of the influenza A H1N1 strains were resistant to Tamiflu, up from .7 percent from the previous flu season, the CDC reported.
The agency noted that it is too early to draw any conclusions about how widespread resistance might be.
The concern would come in the federal government's reliance on Tamiflu to respond to a flu pandemic, when a flu strain mutates enough to cause more widespread illness and result in greater hospitalizations and deaths.
Though Tamiflu is the recommended treatment for the sick, the federal plan calls for essential personnel such as policemen and firemen to take it as protection during a pandemic.
Moreover, the federal government is now urging hospitals and even small businesses to think about stockpiling Tamiflu to protect employees.
"One of the concerns would be if the current (influenza A) H1N1 mutates and the mutated version has the same resistance gene to Tamiflu that H1N1 does right now," Dr. Wilde said. "That would be a recipe for disaster. But it's also quite possible that whatever the pandemic strain is, it will be a strain that is sensitive to Tamiflu."
The bigger concern would be if the trend continues of first one flu strain becoming resistant to the existing antivirals, followed by a different strain, he said.
"We're going in a direction that is quite ominous," Dr. Wilde said.
Reach Tom Corwin at (706) 823-3213 or tom.corwin@augustachronicle.com.
IS IT FLU YET?
Although some community physicians reported a spate of positive flu cases from rapid tests last month, Dr. James Wilde of Medical College of Georgia said he doubts flu is really in the area.
The tests, which studies have shown to be between 55 percent to 90 percent accurate, often give false positives in the absence of a widespread prevalence of flu, he said.
The Centers for Disease Control and Prevention lists both Georgia and South Carolina as having a Sporadic level of flu activity.
GEORGIA: So far, the state has had only one lab confirmed case of flu, although there are seven among soldiers at Fort Benning, according to the Georgia Division of Public Health.
SOUTH CAROLINA: The state's Department of Health and Environmental Control listed one lab-confirmed case from Charleston County as of Dec. 20.
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