Although we did not detect other HCoV types, all HCoV types were detected previously in Brazil in samples collected during 2006-2008 (3,6) . The absence of detection of 229E, OC43, and NL63 HCoV might have resulted from the seasonality and natural viral year cycle or from the characteristics of the children studied This may be the oldest collection of human samples in which HKU1 has been detected. To our knowledge, the oldest previous sample positive for HCoV-HKU1 was detected in children in Finland during 1996-1998, without an exact date specifi ed (7) . Retrospective studies also have been conducted in the United States and Greece that showed the HKU1 virus in different countries in Europe and North America before its discovery (8, 9) . We have confi rmed the circulation of HKU1 coronaviruses in children in Brazil in 1995.