Dear Editor,
Nailya et al. [1] published their findings in Indian Journal of Microbiology, reporting the epidemiology dynamics of respiratory pathogens before and after the coronavirus disease 2019 (COVID-19) pandemic in Kazakhstan. In this study, we explored the impact of the COVID-19 pandemic on infection with Haemophilus parainfluenzae (H. parainfluenzae), one of the leading causes of respiratory tract infection in children, in Henan, China.
H. parainfluenzae is an opportunistic gram-negative, nonmotile pathogen transmitted by droplets of respiratory secretion and easily colonizes the human upper respiratory and urogenital tract [2]. In children under 5 years of age, H. parainfluenzae has been shown to induce systemic conditions such as endocarditis, meningitis, and septicemia. Previous studies presented that the incidence of H. parainfluenzae is increasing year by year, which may be related to the emergence of multidrug resistant strains resistant to β-lactam, cotrimoxazole, tetracycline, and so on. As the main pathogen of respiratory tract in children, H. parainfluenzae is one of the main causes of pneumonia in children [3]. Therefore, detecting and monitoring the changes of H. parainfluenzae infection in children is crucial for exploring control strategies and improve the survival.
Henan Children’s Hospital is a 3A pediatric hospital, which receives more than 10% of the total number of children in Henan province per year. From January 2016 to December 2021, a total of 2120 H. parainfluenzae positive samples were detected in the laboratory of Henan Children's Hospital, of which 91% were obtained from the respiratory tract of children (0–18 years). As shown, the number of H. parainfluenzae infections (Fig. 1A) and the permillage of positive of H. parainfluenzae (Fig. 1B) demonstrated an upward trend year by year before the first outbreak of the COVID-19 pandemic in Henan. In addition, there were two sharp drops of the number and permillage of H. parainfluenzae positive in January 2020 and July 2021, corresponding to outbreaks of the COVID-19 pandemic in Henan. Notably, the two declines in number of H. parainfluenzae infection and positive rate persisted into months after the end of the COVID-19 pandemic outbreaks. Therefore, epidemiological trend of H. parainfluenzae in children had indeed changed after the COVID-19 pandemic in Henan, which may be caused by measures taken in Henan Province, such as closing school, improving the awareness of wearing masks, reducing contact between children, maintaining ventilation, and paying attention to hand hygiene.
Fig. 1.
A The positive number of H. parainfluenzae infection among children aged 0–18 years during January 2016–December 2021. B The permillage of positive H. parainfluenzae infection in children aged 0–18 years during January 2016–December 2021
In addition, infection of H. parainfluenzae were evaluated in different age groups (n = 50 in 0–1 month, n = 1224 in 1 month–2 years, n = 586 in 2–5 years, n = 260 in 5–18 years) before and after the COVID-19 pandemic in this study. It was shown in Fig. 2A that the proportion of H. parainfluenzae infection was more than 88% in children under 5 years of age, indicating that the population of H. parainfluenzae infection is mainly under 5 years old (pre-school children). While, the number of H. parainfluenzae positive decreased after the COVID-19 pandemic in all age groups, with more pronounced change in those over 1 month. Moreover, the monthly number of H. parainfluenzae positive in each of the different age groups showed two sharp drops during the outbreaks of the COVID-19 pandemic in Henan (Fig. 2B). Thus, the epidemiological characteristics of H. parainfluenzae in children of different ages had been affected by the COVID-19 pandemic.
Fig. 2.
A The positive number of H. parainfluenzae infection in children from January 2016 to December 2021. B The positive number of H. parainfluenzae infection by month in four age group from January 2016 to December 2021
In conclusion, the COVID-19 pandemic affected the transmission of H. parainfluenzae in children, specifically referring to the marked decrease of H. parainfluenzae infection in children, especially in pre-school children aged from 1 month to 5 years.
Acknowledgements
This work was funded by the National Natural Science Foundation of China (32201237), China Postdoctoral Science Foundation (2020M672301), Scientific and technological projects of Henan province (222102310270, 222102310109), Henan medical science and technology program (LHGJ 20210618).
Declarations
Conflict of interest
The authors declare no conflicts of interest.
Footnotes
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Contributor Information
Xianwei Zhang, Email: zhangxw956658@126.com.
Wancun Zhang, Email: zhangwancun@126.com.
References
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