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Oseltamivir Ring Prophylaxis for Containment of 2009 H1N1 Influenza Outbreaks
free full text here : http://content.nejm.org/cgi/content/...t/362/23/2166?
ABSTRACT Background From June 22 through June 25, 2009, four outbreaks<sup> </sup>of infection with the pandemic influenza A (H1N1) virus occurred<sup> </sup>in Singapore military camps. We report the efficacy of ring<sup> </sup>chemoprophylaxis (geographically targeted containment by means<sup> </sup>of prophylaxis) with oseltamivir to control outbreaks of 2009<sup> </sup>H1N1 influenza in semiclosed environments.<sup> </sup>
Methods All personnel with suspected infection were tested and<sup> </sup>clinically isolated if infection was confirmed. In addition,<sup> </sup>we administered postexposure ring chemoprophylaxis with oseltamivir<sup> </sup>and segregated the affected military units to contain the spread<sup> </sup>of the virus. All personnel were screened three times weekly<sup> </sup>both for virologic infection, by means of nasopharyngeal swabs<sup> </sup>and reverse-transcriptase?polymerase-chain-reaction assay<sup> </sup>with sequencing, and for clinical symptoms, by means of questionnaires.<sup> </sup>
Results A total of 1175 personnel were at risk across the four<sup> </sup>sites, with 1100 receiving oseltamivir prophylaxis. A total<sup> </sup>of 75 personnel (6.4%) were infected before the intervention,<sup> </sup>and 7 (0.6%) after the intervention. There was a significant<sup> </sup>reduction in the overall reproductive number (the number of<sup> </sup>new cases attributable to the index case), from 1.91 (95% credible<sup> </sup>interval, 1.50 to 2.36) before the intervention to 0.11 (95%<sup> </sup>credible interval, 0.05 to 0.20) after the intervention. Three<sup> </sup>of the four outbreaks showed a significant reduction in the<sup> </sup>rate of infection after the intervention. Molecular analysis<sup> </sup>revealed that all four outbreaks were derived from the New York<sup> </sup>lineage of the 2009 H1N1 virus and that cases within each outbreak<sup> </sup>were due to transmission rather than unrelated episodes of infection.<sup> </sup>Of the 816 personnel treated with oseltamivir who were surveyed,<sup> </sup>63 (7.7%) reported mild, nonrespiratory side effects of the<sup> </sup>drug, with no severe adverse events.<sup> </sup>
Conclusions Oseltamivir ring chemoprophylaxis, together with<sup> </sup>prompt identification and isolation of infected personnel, was<sup> </sup>effective in reducing the impact of outbreaks of 2009 H1N1 influenza<sup> </sup>in semiclosed settings
free full text here : http://content.nejm.org/cgi/content/...t/362/23/2166?
ABSTRACT Background From June 22 through June 25, 2009, four outbreaks<sup> </sup>of infection with the pandemic influenza A (H1N1) virus occurred<sup> </sup>in Singapore military camps. We report the efficacy of ring<sup> </sup>chemoprophylaxis (geographically targeted containment by means<sup> </sup>of prophylaxis) with oseltamivir to control outbreaks of 2009<sup> </sup>H1N1 influenza in semiclosed environments.<sup> </sup>
Methods All personnel with suspected infection were tested and<sup> </sup>clinically isolated if infection was confirmed. In addition,<sup> </sup>we administered postexposure ring chemoprophylaxis with oseltamivir<sup> </sup>and segregated the affected military units to contain the spread<sup> </sup>of the virus. All personnel were screened three times weekly<sup> </sup>both for virologic infection, by means of nasopharyngeal swabs<sup> </sup>and reverse-transcriptase?polymerase-chain-reaction assay<sup> </sup>with sequencing, and for clinical symptoms, by means of questionnaires.<sup> </sup>
Results A total of 1175 personnel were at risk across the four<sup> </sup>sites, with 1100 receiving oseltamivir prophylaxis. A total<sup> </sup>of 75 personnel (6.4%) were infected before the intervention,<sup> </sup>and 7 (0.6%) after the intervention. There was a significant<sup> </sup>reduction in the overall reproductive number (the number of<sup> </sup>new cases attributable to the index case), from 1.91 (95% credible<sup> </sup>interval, 1.50 to 2.36) before the intervention to 0.11 (95%<sup> </sup>credible interval, 0.05 to 0.20) after the intervention. Three<sup> </sup>of the four outbreaks showed a significant reduction in the<sup> </sup>rate of infection after the intervention. Molecular analysis<sup> </sup>revealed that all four outbreaks were derived from the New York<sup> </sup>lineage of the 2009 H1N1 virus and that cases within each outbreak<sup> </sup>were due to transmission rather than unrelated episodes of infection.<sup> </sup>Of the 816 personnel treated with oseltamivir who were surveyed,<sup> </sup>63 (7.7%) reported mild, nonrespiratory side effects of the<sup> </sup>drug, with no severe adverse events.<sup> </sup>
Conclusions Oseltamivir ring chemoprophylaxis, together with<sup> </sup>prompt identification and isolation of infected personnel, was<sup> </sup>effective in reducing the impact of outbreaks of 2009 H1N1 influenza<sup> </sup>in semiclosed settings