Changes of parainfluenza virus infection in children before and after the COVID-19 pandemic in Henan, China

Infections of Streptococcus pneumoniae and Haemophilus influenza in children were affected by the COVID-19 pandemic, which were reported by Li et al.1Li Y. Guo Y. Duan Y. Changes in Streptococcus pneumoniae infection in children before and after the COVID-19 pandemic in Zhengzhou, China.J Infect. 2022; 85: e80-e81Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar and Zhou et al.2Zhou J. Zhao P. Nie M. Gao K. Yang J. Sun J. Changes of Haemophilus influenzae infection in children before and after the COVID-19 pandemic, Henan, China.J Infect. 2023; 86: 66-117Abstract Full Text Full Text PDF Scopus (14) Google Scholar in the journal of infection. Changed respiratory syncytial virus infection in children was also reported by Zhang et al.3Zhang M. Gao J. Guo Q. Zhang X. Zhang W. Changes of respiratory syncytial virus infection in children before and after the COVID-19 pandemic in Henan, China.J Infect. 2022; 86: 154-225Abstract Full Text Full Text PDF Scopus (3) Google Scholar However, the epidemiological features of parainfluenza virus (PIV) have not been reported. Here, we reported the changes of PIV infections in children before and after the COVID-19 pandemic in Henan, China. Parainfluenza virus is an enveloped, negative-sense, single-stranded RNA virus belonging to the Paramyxoviridae family,4Marcink T.C. Porotto M. Moscona A. Parainfluenza virus entry at the onset of infection.Adv Virus Res. 2021; 111: 1-29Crossref PubMed Scopus (2) Google Scholar which has influence on young children especially children under 5 years old.5Pan Y. Zhang Y. Shi W. Peng X. Cui S. Zhang D. et al.Human parainfluenza virus infection in severe acute respiratory infection cases in Beijing, 2014-2016: a molecular epidemiological study.Influenza Other Respir Viruses. 2017; 11: 564-568Crossref PubMed Scopus (22) Google Scholar As one of the most common pathogens of acute lower respiratory tract infection (ALRI), 13% of ALRI, 4–14% of ALRI hospital admissions, and 4% of childhood ALRI mortality were attributed to PIV.6Wang X. Li Y. Deloria-Knoll M. Madhi S.A. Cohen C. Arguelles V. et al.Global burden of acute lower respiratory infection associated with human parainfluenza virus in children younger than 5 years for 2018: a systematic review and meta-analysis.Lancet Glob Health. 2021; 9: e1077-e1087Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar Statistically, PIV coinfection with other viruses and atypical bacteria could induce more serious clinical manifestations than single infection.7Zhong P. Zhang H. Chen X. Lv F. Clinical characteristics of the lower respiratory tract infection caused by a single infection or coinfection of the human parainfluenza virus in children.J Med Virol. 2019; 91: 1625-1632Crossref PubMed Scopus (12) Google Scholar Spring and early summer are the common epidemic seasons of PIV.8Li Y. Reeves R.M. Wang X. Bassat Q. Abdullah Brooks W. Cohen C. et al.Global patterns in monthly activity of influenza virus, respiratory syncytial virus, parainfluenza virus, and metapneumovirus: a systematic analysis.Lancet Glob Health. 2019; 7: e1031-e1045Abstract Full Text Full Text PDF PubMed Scopus (169) Google Scholar The non-pharmaceutical interventions implemented to control the COVID-19 pandemic have affected the transmission of other respiratory viruses, such as respiratory syncytial virus.9Williams T.C. Sinha I. Barr I.G. Zambon M. Transmission of paediatric respiratory syncytial virus and influenza in the wake of the COVID-19 pandemic.Euro Surveill. 2021; 26Crossref Scopus (32) Google Scholar Measures such as wearing masks, keeping social distance, limiting crowd gathering and restricting outdoor activities could also influence the prevalence of pediatric PIV epidemics. Therefore, retrospectively analyzing the changes of PIV infections before and after the COVID-19 pandemic could provide insights for the prevention and control of PIV infection in children. To assess the impact of the COVID-19 pandemic on the epidemiological characteristics of children with PIV infection, we analyzed the data in Henan Children’s Hospital from January 2018 to December 2022. A total of 152,840 children were included (n = 46,510 in 2018, n = 42,529 in 2019, n = 25,390 in 2020, n = 24,636 in 2021, n = 13,775 in 2022) with IgM testing records for PIV detection. As shown in Fig. 1A, both number of total cases and PIV-positive cases decreased in 2020, 2021, and 2022, compared to 2018 and 2019. The positive rate in 2020 showed obvious shrink trend, whereas it raised in 2021 (Fig. 1B). We also conducted analysis of the monthly distribution of PIV infection from 2018 to 2022 (Fig. 1C). Our data showed that spring and summer were the common seasons of pediatric PIV infection in the pre-pandemic period (2018 and 2019), while the detection rate of PIV infection peaked in December in 2020 and January in 2021 after the pandemic. The positive rate reduced to the minimum during the three COVID-19 outbreaks, when the city was lockdown. These results suggest that the COVID-19 pandemic has a significant impact on the epidemiological characteristics of PIV infections among children. Furthermore, PIV positive number and rates were evaluated in six age groups (0–28 days, 29 days-1 year, 1–3 years, 3–7 years, 7–12 years, 12–18 years) as shown in Fig. 2. The PIV-positive children concentrated in 3–7 years old, and were rare in infants and puberty. The positive number decreased in each age groups (except 12–18 years) after the COVID-19 pandemic compared to 2018 and 2019 (Fig. 2A). The 3–7 y group accounting for the highest positive rate showed an obvious downward trend in 2020, even though it rebounded in 2021 and 2022, it was still lower than the pre-epidemic level. Positive rates of 7–12 y and 12–18 y groups post-pandemic grew and higher than the pre-pandemic period (Fig. 2B), which indicated that the COVID-19 pandemic might result the increasing PIV susceptible age. These results suggest that the COVID-19 pandemic may also affect the age distribution of PIV infections among children. In conclusion, the COVID-19 pandemic had changed the epidemiological characteristics of pediatric PIV infections. Intermittent outbreaks of the COVID-19 pandemic had significantly reduced PIV infection cases and the season distribution of PIV prevalence. The preschoolers aged in 3–7 years old should be the primary focus in the continuous surveillance of PIV infection, and close monitoring of children over 7 years old is also of significance. Continuous monitoring of PIV infection will be helpful for the prevention and control of related infectious diseases. The authors declare no conflict of interests. This work was supported by grants from the National Natural Science Foundation of China (31900116) and the Medical Science and Technology Projects of Henan Province (LHGJ20190955).