Embargoed until 5:30 p.m. EST, Wednesday, Nov. 1Per New England Journal of Medicine
CONTACT: Marguerite Beck, DirectorU.Va. Health System Media Relations804-924-5679[email protected]
SPREAD OF FLU IN FAMILIES REDUCED WITH ZANAMIVIR
CHARLOTTESVILLE, Va., November 1-- Families like to share a lot of things, but the flu shouldn't be one of them. A new study, published in the Nov. 2 issue of The New England Journal of Medicine, found that zanamivir can prevent the flu from making the rounds within a family when one member becomes infected.
"The close interaction of the typical family makes it easy for influenza to spread throughout a household," said Dr. Frederick Hayden, professor of internal medicine at the University of Virginia Health System and lead investigator of the study. "Because it can quickly reduce the transmission of the virus, inhaled zanamivir shows great promise as a way to curb this common domestic epidemic."
The double-blind, placebo-controlled clinical trial was designed to examine the effectiveness of zanamivir in preventing the spread of influenza A and B from one infected family member to other members. During the influenza season, ill individuals with suspected influenza were randomized to receive either treatment with zanamivir or placebo (10 mg twice daily for five days). Their well family members not infected with flu received the same blinded medication once daily for prevention of illness (10 mg once a day for ten days).
Results showed that zanamivir significantly reduced the risk of acquiring the flu by 79 percent. Out of 337 total families, 19 percent receiving placebo had one or more members who developed laboratory confirmed influenza during prophylaxis as compared with only four percent in the group receiving zanamivir.
"Families tell us that the spread of influenza in the household is a serious problem, and sometimes turns into weeks of illness that can significantly disrupt their day-to-day activities," Hayden said. "Vaccine is the primary means of influenza prevention, particularly for elderly and high risk individuals, but it takes several weeks for full responses to develop after immunization. This study shows that zanamivir provides rapid protection after exposure so that we may have an additional way to prevent the disruption that influenza can cause in families."
The most common side effects for both treatment and prophylaxis included respiratory illness (17 percent placebo vs. 10 percent zanamivir), headaches (10 percent vs. 9 percent) and nasal signs and symptoms (8 percent vs. 9 percent).
Health care professionals have been reluctant to use one anti-influenza agent for both treatment and prevention in the same household due to the resistance problems that were seen with the older drugs amantadine and rimantadine. However, in this study no resistance was observed with zanamivir.
Zanamivir, an inhaled neuraminidase inhibitor, received approval for treatment of influenza from the U.S. Food and Drug Administration (FDA) in 1999 and is currently approved to age seven. It is currently investigational for prevention and is under review by the FDA for this indication.
Influenza or flu is a viral infection that resides primarily in the lungs and typically causes significant disease that can be incapacitating. Flu affects approximately 25 million people each year in the U.S., the majority of whom are not vaccinated. During an average year, influenza causes over 20,000 excess deaths, results in as many as 300,000 hospitalizations, and is associated with combined direct and indirect healthcare costs of about $12 billion per year.
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