According to a group of industry and academic investigators, Infants less than one year of age were four times more likely to receive anti-viral treatment (AVT) during the H1N1 2009 pandemic flu season compared with the three pre-pandemic seasons of 2006-2007, 2007-2008, and 2008-2009).
The use of AVT was associated with reduced risk for Influenza (INF)-related complications and hospitalization.
A retrospective analysis of a database of more than 124 million covered lives identified 19,666 infants <1 year with influenza, including 9680 infants from the pandemic and 9986 infants from the 2006-2009 seasons combined.
During the pandemic, complication rates were lower than during the pre-pandemic years (51.9 vs 60.4 per 100 person-months; odds ratio [OR] 0.91, P
=0.005). And AVT use was more frequent (33.0% vs 7.4%), with a shorter mean duration of treatment (6.2 vs 7.5 days). Onset of diagnosis to initiation of AVT was quicker in the pandemic compared to pre-pandemic years (mean 0.3 +/-1.8 vs 0.7 +/-3.2 days); overall, 98.4% received AVT within 48 hours of INF onset. According to the researchers, oseltamivir accounted for 99% and 89% of treatment courses during the pandemic and pre-pandemic years, respectively. The use of AVT was shown to reduce the risk of INF-related complications by 12% (adjusted odds ratio [aOR] 0.88) and 39% (aOR 0.61) during the pandemic and pre-pandemic years, respectively, and by 20% overall (aOR 0.80). Finally, hospitalization occurred in 3.35% of infants <1 year of age with INF diagnosis. AVT also reduced hospitalization risk overall by 23% (aOR=0.77).