TY - JOUR AU - Dowell, Scott F. AU - Whitney, Cynthia G. AU - Wright, Carolyn AU - Rose, Charles E. AU - Schuchat, Anne T1 - Seasonal Patterns of Invasive Pneumococcal Disease T2 - Emerging Infectious Disease journal PY - 2003 VL - 9 IS - 5 SP - 574 SN - 1080-6059 AB - Pneumococcal infections increase each winter, a phenomenon that has not been well explained. We conducted population-based active surveillance for all cases of invasive pneumococcal disease in seven states; plotted annualized weekly rates by geographic location, age, and latitude; and assessed correlations by time-series analysis. In all geographic areas, invasive pneumococcal disease exhibited a distinct winter seasonality, including an increase among children in the fall preceding that for adults and a sharp spike in incidence among adults each year between December 24 and January 7. Pneumococcal disease correlated inversely with temperature (r –0.82 with a 1-week lag; p<0.0001), but paradoxically the coldest states had the lowest rates, and no threshold temperature could be identified. The pattern of disease correlated directly with the sinusoidal variations in photoperiod (r +0.85 with a 5-week lag; p<0.0001). Seemingly unrelated seasonal phenomena were also somewhat correlated. The reproducible seasonal patterns in varied geographic locations are consistent with the hypothesis that nationwide seasonal changes such as photoperiod-dependent variation in host susceptibility may underlie pneumococcal seasonality, but caution is indicated in assigning causality as a result of such correlations. KW - Streptococcus pneumoniae KW - seasons KW - pneumonia KW - weather KW - infection KW - communicable disease KW - temperature KW - photoperiod KW - child KW - research KW - United States DO - 10.3201/eid0905.020556 UR - https://wwwnc.cdc.gov/eid/article/9/5/02-0556_article ER - End of Reference