An extensive study conducted at Hangzhou Children’s Hospital investigated the epidemiological characteristics of enteroviruses among children from 2018 to 2023. The study included 9,676 pediatric cases, of which 5,838 (60.33%) tested positive for enterovirus (EV) through robust molecular detection methods.
The research specifically aimed to analyze cases manifesting with viral encephalitis, leveraging real-time quantitative polymerase chain reaction (qPCR) for accurate nucleic acid detection in samples collected from throat swabs or feces. The findings underscore the ongoing health challenges posed by enterovirus infections, especially as specific strains, such as Coxsackievirus (CV), continue to prevail.
Among the positive cases, researchers documented 1,909 infections due to Coxsackievirus group A type 6 (CV-A6), representing 32.70% of the total detected cases. Lower numbers were seen for Coxsackievirus A type 16 (CV-A16) at 259 cases (4.44%), type 10 (CV-A10) at 252 cases (4.32%), and enterovirus type 71 (EV-A71) with only 34 cases (0.58%). The data revealed that over half of the infected children (57.97%) harbored other uncategorized enteroviruses, indicating a diverse viral landscape.
The researchers noted a concerning trend: the detection rates of EV-A71 and CV-A16 have been diminishing yearly since 2018, while other strains have shown increased prevalence. This shift may signal a changing epidemiological landscape for enterovirus infections in the region.
In a subset of 1,520 children showing clinical presentations consistent with encephalitis, cerebrospinal fluid (CSF) testing resulted in 140 positive cases (9.21%). The analysis included 13 cases (9.29%) attributed to CV-A6, while CV-A16 and CV-A10 recorded just two and three cases, respectively. Alarmingly, none of the CSF samples tested positive for EV-A71, raising questions about the virus's roles in severe manifestations.
Among these 140 positive children, clinical symptoms varied, with 32 exhibiting typical signs of hand-foot-mouth disease or herpetic angina, while 108 presented with only fever and upper respiratory infections. The multifaceted presentations of enterovirus infections emphasize the need for comprehensive diagnostic efforts.
The authors remarked that real-time qPCR techniques substantially improve the accuracy of enterovirus diagnoses. They reinforced the importance of conducting multi-sample nucleic acid testing when evaluating children suspected of viral encephalitis, as it enhances the diagnostic yield and may change clinical outcomes dramatically.
Notably, the study highlights the introduction of a monovalent vaccine targeting EV-A71 in 2016, which had previously led to a significant drop in severe cases and mortality linked to this serotype. However, despite an impressive vaccination rate of 24.1% observed in Zhejiang Province, cases of other enteroviruses have not declined proportionately as infections with CV-A6 rise.
According to the authors, the data strongly indicate that while the vaccine effectively mitigated severe outcomes from EV-A71, the emergence of new serotypes calls for a multivalent vaccine approach to tackle the evolving landscape of enterovirus infections among children.
The researchers concluded that understanding the epidemiological characteristics of EV infections is crucial for developing effective public health strategies. Given the dynamic nature of enterovirus serotypes and their links to serious clinical conditions like encephalitis, continuous surveillance and the exploration of advanced diagnostic methods are essential.
As the study notes, effective vaccines will remain the cornerstone in preventing and controlling enterovirus infections. With ongoing efforts to develop multivalent vaccines, the fight against these prevalent pathogens continues, aiming to reduce the burden of disease in pediatric populations.
