In a pandemic caused by a new strain of flu virus, new vaccines would need to be developed to cope with changes the virus creates to escape immune detection in host animals. But vaccines take six months or longer to develop and produce in quantity. In the event of an influenza pandemic, when a virulent new form of the flu virus emerges and poses a global health threat, antiviral drugs are viewed as a stopgap, a way to buy time while new vaccines are developed and rushed into production.
The last flu pandemic was in 1968. The influenza pandemic of 1918 was a global tragedy, claiming 21 million lives - more than died in battle in World War I. One billion people - nearly half of the earth's population at the time - were infected.
The new study of Japanese children portrays what might happen in a pandemic as the immune system of a child, never before exposed to a flu virus, mirrors the adult human immune system exposed to the new, more virulent forms of flu virus at the root of pandemics.
"Most of the children we looked at are younger than 3 years old," Kawaoka explains. "They're encountering the flu virus for the first time. In this respect, our population of patients might be considered comparable to one experiencing pandemic influenza in the absence of pre-existing immunity."
The study of 50 Japanese children with influenza, says Kawaoka, suggests that oseltamivir-resistant viruses arise frequently in children treated with the drug.
"We don't know how virulent these viruses are, but they can be a source of another infection, possibly by resistant viruses," he says.
Oseltamivir is a well-known drug and is widely used in Japan. Its use in the United States is restricted, primarily because of cost.
Kawaoka emphasized that while the emergence of resistant flu virus was worrisome, the compound oseltamivir is still a valuable therapeutic drug.
"This is still a good compound," he says. "As with any antiviPage: 1 2 3 Related biology news :1
Contact: Yoshihiro Kawaoka
University of Wisconsin-Madison
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