Epidemiology and Clinical Characteristics of Parainfluenza Virus Type 4 in Korean Children: a Single Center Study, 2015–2017

Seasonal epidemiological and clinical characteristics of pediatric patients with human parainfluenza virus infection by serotype: a retrospective study

“…Most previous epidemiological studies showed biennial epidemics of HPIV-1 and HPIV-2 in autumn [ 1 , 3 , 10 , 11 ]. In this study, HPIV-1 was epidemic in annual autumn in 2015–2017, consistent with previously reported results in Korean children in 2013–2017 [ 17 , 18 ]. Whereas, HPIV-1 infection was widespread from spring to autumn in 2018 and 2019, which was consistent with a Chinese study showing fluctuations without distinct seasonality of HPIV-1 [ 15 , 21 ].…”

“…In this study, it was reaffirmed that HPIV infection occurred mostly in young children, with a peak between spring and autumn, and caused a range of respiratory tract infections [ 1 , 3 , 8 , 10 ]. HPIV-3 was the most prevalent among the four serotypes, consistent to the previously reported results [ 10 , 11 , 15 , 17 – 19 ], and similar seasonal trends and clinical characteristics of HPIV-3 infection to those previously reported were identified: HPIV-3 was prevalent in spring and summer annually [ 1 , 3 , 8 – 11 , 15 , 17 – 19 ], patients infected by HPIV-3 tended to be younger than those infected by other serotypes [ 1 , 3 , 9 , 18 ], and croup was diagnosed infrequently [ 3 , 8 , 9 , 16 – 18 ]. Therefore, we can regard HPIV infections in spring and summer as non-specific URI or LRI rather than croup, caused by HPIV-3 in young children and infants.…”

“…Whereas, HPIV-1 infection was widespread from spring to autumn in 2018 and 2019, which was consistent with a Chinese study showing fluctuations without distinct seasonality of HPIV-1 [ 15 , 21 ]. The seasonality of HPIV-2 was more varied than that of HPIV-1: epidemics in biennial autumn, annual autumn, and annual winter were reported [ 1 , 3 , 9 – 11 , 17 , 18 , 22 ], and some studies failed to find a distinct seasonality of HPIV-2 [ 8 , 15 , 16 , 19 , 21 ]. In this study, HPIV-2 was prevalent in autumn as a whole; however, a regular seasonality could not be defined due to the lowest number of HPIV-2 identification among the four serotypes, clustered in 2015 and 2019.…”

“…In this study, HPIV-4 was prevalent in autumn as a whole; however, it was prevalent in spring in 2017 and the numbers of identification varied year to year. Nationwide studies for several years in the UK and USA reported annual epidemics of HPIV-4 in autumn [ 10 , 11 ], while Korean and Chinese studies with ≤ 5 years of study period reported fluctuating seasonal patterns of HPIV-4 [ 15 , 17 – 19 , 21 ]. As a result, the seasonality of HPIV types 1, 2, and 4 varied according to geographic area, study duration, patient number, and identification method in previous reports and this study.…”

Shift in Clinical Epidemiology of Human Parainfluenza Virus Type 3 and Respiratory Syncytial Virus B Infections in Korean Children Before and During the COVID-19 Pandemic: A Multicenter Retrospective Study

“…Considering the usual epidemic pattern of PIV3, which is predominant from late spring to summer, 11 12 the 2021 PIV3 outbreak was unusual and unpredictable. While there has been an increasing number of studies on RSV resurgence, 13 14 little has been reported about the epidemiologic changes in PIV during the COVID-19 pandemic.…”