Preventive program associated with reduced spread of H1N1 at summer camp

A targeted program of preventive antiviral medication, combined with the use of hand sanitisers and surface decontamination, was associated with containing the spread of the H1N1 virus in a summer camp setting, according to a report posted online today that will appear in the April print issue of Archives of Pediatrics and Adolescent Medicine, one of the JAMA/Archives journals.

Since spring 2009, millions of Americans have been infected with the novel influenza A(H1N1) virus and thousands of people have died, according to background information in the article. Children have been particularly vulnerable to this strain, which in an unusual turn of events continued to spread and cause disease throughout the summer of 2009. 'With large numbers of children from disparate locales coming together and living in communal settings, summer camps are uniquely suited to experience outbreaks of novel influenza A(H1N1) and potentially to contribute to the virus' ongoing spread during a period of the year when influenza typically is very uncommon,' the authors write.

With rare exceptions, the H1N1 virus has retained sensitivity to the antiviral medication oseltamivir phosphate. The drug has been proven to prevent the spread of seasonal flu in settings such as households and nursing homes. David W. Kimberlin, M.D., of the University of Alabama at Birmingham, and colleagues described targeted use of this drug for containing the spread of H1N1 at a boys' camp in Alabama in July 2009.

A total of 171 campers, 48 camp counsellors and 27 camp staff were involved in this program. Three campers tested positive for H1N1 during one of the camp's two-week sessions. These campers received oseltamivir and were immediately isolated and sent home. All campers and counsellors in the infected child's adjoining cabins took oseltamivir prophylactically (to prevent infection) for 10 days.

'Alcohol-based hand sanitiser was provided at each of the daily activities, in the boys' cabins and in the dining hall, and counsellors were educated by the medical staff on the spread of influenza and its prevention through good hand hygiene,' the authors write. 'All cabins, bathrooms and community sports equipment were sprayed or wiped down with disinfectant each day.'

No additional campers, counsellors or staff members became ill during the session and no campers tested positive for H1N1 after returning home. The three infected campers constituted an attack rate (the percentage of individuals who get sick out of the total population) of 1.8 percent.

The majority of staff and counsellors (51 of 65, or 78 percent) and about 31 percent of campers experienced one or more adverse events, such as nausea, vomiting or headache, from the medication. However, none of the adverse events resulted in discontinuation of the therapy.

'In conjunction with aggressive hand sanitisation and surface decontamination, a targeted approach to antiviral prophylaxis contained the spread of influenza in a summer camp setting,' the authors conclude. 'Additional controlled studies randomising camps to specific components of the interventions used here would be needed to fully understand the relative benefits of each.'