Abstract:
Objective To investigate the epidemiological characteristics of human parainfluenza virus (HPIV) in Pudong New Area, Shanghai, and to provide a basis for the prevention and control of HPIV infections in this area.
Methods A total of 8 180 cases with acute respiratory infection (ARI)/influenza-like illness (ILI) attending the fever outpatient clinics, pediatric outpatient clinics, respiratory outpatient clinics, pediatric wards, emergency departments, respiratory wards, and intensive care units (ICUs) and other monitoring departments in 9 sentinel hospitals in Pudong New Area from 2017 to 2022 were selected as the research subjects, and their nasopharyngeal/ throat swabs were collected. Polymerase chain reaction (PCR) method was performed for testing the respiratory virus such as influenza virus, human adenovirus, human parainfluenza virus, respiratory syncytial virus (RSV), human enterovirus, rhinovirus, et al. HPIV serotypes were analyzed, and the detection rates of HPIV were compared between different times, seasons, and population groups.
Results The overall HPIV detection rate of ARI/ILI cases in Pudong New Area was 3.73% (305/8 180) in 2017‒2022, with HPIV-3 being the predominant serotype. The detection rate of HPIV decreased significantly in 2017‒2022, peaking at 7.66% (99/1 293) in 2017 and falling to 0.80% (13/1 617) in 2021. Statistically significant differences were observed in HPIV detection rates across different years (χ2trend=80.037, Ptrend<0.001). The detection rate was higher in 2017‒2019 than that in 2020‒2022 (χ2trend=38.990, Ptrend<0.001). HPIV exhibited seasonal patterns in 2017‒2019, with higher detection rates in summer and autumn and lower in spring and winter, whereas no seasonal patterns were observed in 2020‒2022. Children aged <6 years had the highest detection rate (7.07%, 139/1 967), followed by adults aged ≥60 years (4.78%, 85/1 779). Statistically significant differences were observed in the detection rates of HPIV among different age groups (χ2=111.210, P<0.001). Symptoms of HPIV infection were predominantly cough, fever, and runny nose in pre-school children, fever, cough, and sore throat in school-age children, and adults, and cough, expectoration, and fever in the elderly.
Conclusion The HPIV detection rate in Pudong New Area was low in 2017‒2022. The seasonal pattern of HPIV circulation in Pudong New Area disappeared in 2020‒2022 due to the influence of infectious disease epidemics. Young children and the elderly should be prioritized in HPIV prevention and control efforts.