LAUSR

Background. Human coronaviruses (HCoV) OC43, 229E, NL63 and HKU1 commonly cause upper respiratory tract infections, but can also cause severe lower respiratory tract disease. Increased use of diagnostic assays for respiratory viruses has facilitated detection and, since 2014, voluntary reporting of HCoV to the National Respiratory and Enteric Virus Surveillance System (NREVSS). Methods. We reviewed weekly aggregate test results for HCoV OC43, 229E, NL63 and HKU1 voluntarily reported to NREVSS by U.S. hospital and clinical laboratories from July 1, 2014‒April 30, 2017. Laboratories reporting any HCoV result using PCR were included, and the weekly percentage of positive HCoV tests by type was calculated. For a subset of HCoV detections reported to NREVSS via the Public Health laboratory Interoperability Project (PHLIP), which collects individual-level demographic data, we described age distribution and sex. Age distribution by HCoV type was compared using the Kruskal–Wallis test. Results. 154 laboratories, across all 9 U.S. census divisions, reported 834,742 tests for HCoV; 18,514 (2.2%) were positive for HCoV-OC43, 8,363 (1.0%) for HCoV-NL63, 6,828 (0.8%) for HCoV-229E, and 5,170 (0.6%) for HCoV-HKU1. The percentage of tests positive for HCoV generally peaked between December and March (Figure 1). HCoV-OC43 showed distinct annual peaks with variation in magnitude by year. HCoV-HKU1 and NL63 had similar patterns, each with notable peaks during winter 2016 compared with 2015 or 2017. HCoV-229E showed a discernable peak in 2017 compared with the previous 2 years. Of 20,533 individuals with HCoV test results reported via PHLIP, 1,589 (7.7%) tested positive for any HCoV; 50% of HCoV-positive individuals were male, and the median age was 22 (range 0–96) years. Age distribution differed between HCoV types (P < 0.01, Figure 2). Conclusion. Over approximately 3 seasons, peak positivity for HCoV occurred during winter months, and annual differences in circulation by HCoV type were observed. Continued testing and surveillance for HCoV will allow for further characterization of circulation trends over time and by geographic region, and improved understanding of the contribution of HCoV to the winter respiratory virus season.