Children suspicious of severe bacterial infection in PICU are a frequent challenge for pediatricians, which if not handle with timely appropriate treatment would result in poor prognosis [6]. Bacterial infections in PICU include community acquired infection (CAI) and hospital acquired infection (HAI). This study collected data from patients with community-acquired bacterial infections admitted to PICUs in 6 representative medical centers from different regions of mainland China in 2019 and 2021.
This is a retrospective study based on infection distribution in the PICU of six medical centers and it revealed a decrease in the total number of children's hospitalizations in 2021 compared to 2019. Studies have reported that quarantine prevention and control measures reduce COVID-19 cases. The timing of prevention and control strategies is strongly associated with the trending decline in the epidemic growth rate of COVID-19 cases [7–9]. While quarantine measures are implemented to contain the spread of COVID-19, the incidence of acute respiratory illnesses, respiratory syncytial virus and influenza acute respiratory illnesses in children also decreased [1]. The medical centers involved in this study were under the epidemic prevention and control measures in 2020. Thus, after 2020, the behavioral patterns of the people in 2021 have changed greatly from those in 2019. This conclusions of this study are consistent with previous reports that the number of hospitalizations reduced in 2021 as compared to 2019 might also be attributable to nationwide prevention and control measures, including control of the movement of people, mass disinfection, suspension of classes, work, and maximum use of masks and other protective measures. It should also be taken into consideration that the epidemic prevention and control measures have caused more patients to choose local hospitals for treatment, rather than being referred to higher-level hospitals across regions, which also explains the reduction in the number of hospitalizations.
In the present study, the number of bacterial infections in 2021 was lower than that in 2019. Of note, bacterial infection is an important complication of influenza pandemic [2]. Treatment of viral infection is anticipated to prevent bacterial superinfections. For example, oral osltamivir anti viral (type A and type B). Although the number of bacterial infections decreased in 2021 as compared with 2019, there was no difference in the distribution of infection sites, and the respiratory system was still the main infection site for bacterial infections in the PICU.
Previous studies have shown that Haemophilus influenzae and Streptococcus pneumoniae are the main pathogens in PICU [10]. Our study found a decrease in the rate of Haemophilus influenzae infections. Haemophilus influenzae, as an opportunistic pathogen, can cause a variety of clinical symptoms including otitis media, epiglottitis, sinusitis, and pneumonia, especially in children, the elderly, and immunocompromised patients. Haemophilus influenzae is mainly transmitted through respiratory droplets from carriers [11]. This result is consistent with the conclusions of previous studies [12, 13]. The various prevention and control measures during the epidemic could possibly cut off the pathogenic infection mainly dependent on the transmission of respiratory droplets [1]. However, a limitation of this study was that we failed to isolate the serotype of Haemophilus influenzae. In addition, unlike Haemophilus influenzae, our study found that the rate of Streptococcus pneumoniae infection in 2021 was higher than that in 2019. Previous studies have shown that for severe community acquired pneumonia patients in intensive care unit, influenza is a risk factor for bacterial infection and Streptococcus pneumoniae is the most common bacterium among the major complications of influenza pandemic [2]. Therefore, theoretically, streptococcus pneumoniae infection secondary to virus infection should be reduced with declined rate of influenza, which is contrary to the results of this study. We speculate that the increase in streptococcus pneumoniae infection is possibly relative to the reduced mass movement during the epidemic prevention and control measures, and the decreased vaccination of streptococcus pneumoniae [14, 15]. In addition, CDC suggested that patients with positive diagnosis of covid-19 should delay routine immunization during the covid-19 pandemic [16]. However, due to the small sample size, no statistical difference between the two years was found. Therefore, a large sample size and long-term observation is necessary for evaluating the changes in streptococcus pneumoniae infection over the years.
Moreover, we found that the mortality of children with former medical history was 31.9% in 2019 and 44.0% in 2021. Although the rate of hospitalization and bacterial infections in 2021 decreased, the mortality in children with former medical history increased, suggesting that epidemic prevention and control measures may be of some significance for the prevention of infectious diseases in healthy children, but children with previous medical history will need more protection and attention. However, due to the small sample size, there was no statistical difference between the two years, and further research and confirmation are needed for verification.