School opening dates predict pandemic influenza A(H1N1) outbreaks in the United States.
The opening of schools in the late summer of 2009 may have triggered the fall wave of pandemic influenza A(H1N1) in the United States. We found that an elevated percentage of outpatient visits for influenza-like illness occurred an average of 14 days after schools opened in the fall of 2009. The timing of these events was highly correlated (Spearman correlation coefficient, 0.62; P<.001). This result provides evidence that transmission in schools catalyzes community-wide transmission. School opening dates can be useful for future pandemic planning, and influenza mitigation strategies should be targeted at school populations before the influenza season.
Chao
Dennis L
DL
Center for Statistics and Quantitative Infectious Diseases, Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA. dchao@fhcrc.org
Halloran
M Elizabeth
ME
Longini
Ira M
IM
D005544:Forecasting / Q000379:methods*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D011153:Population; D012574:Schools; D018571:Sentinel Surveillance; D013997:Time Factors; D014481:United States / Q000453:epidemiology