Risk factors for death in children with severe hand, foot, and mouth disease in Hunan, China

Clinical, aetiological, and epidemiological studies of outpatient cases of hand, foot, and mouth disease in Chengdu, China, from 2019 to 2022: a retrospective study

BACKGROUND

The introduction of the Enterovirus A71 (EV-A71) vaccine in China in 2016 has led to a considerable decline in severe hand, foot, and mouth disease (HFMD) cases, with mild outpatient instances now representing the majority of HFMD cases in the country. Nevertheless, epidemiological investigations concerning mild outpatient cases remain scarce, resulting in inadequate descriptions of their clinical, etiological, and epidemiological characteristics. Our study aimed to analyze the clinical, etiological, and epidemiological characteristics of HFMD outpatients in Chengdu from 2019 to 2022 while identifying potential risk factors associated with the progression of outpatients requiring hospitalization.

METHODS

A retrospective study was conducted to summarize the clinical, etiological, and epidemiological characteristics of outpatient HFMD cases in Chengdu from 2019 to 2022. Risk factors associated with progression to hospitalization of HFMD outpatients were evaluated using binomial logistic regression analysis.

RESULTS

The study included 1,073 coxsackievirus A6 (CVA6), coxsackievirus A10 (CVA10), and coxsackievirus A16 (CVA16) HFMD nucleic acid test-positive outpatients. Among these, only 45 outpatients (4.19%) progressed to hospitalization. The median ages for CVA6, CVA10, and CVA16 infections were 25.23, 28.13, and 38.45 months, respectively (P < 0.001). CVA6 (76.51%, 821/1,073) has become the main serotype among outpatients in Chengdu, with the proportions from the second half of 2019 to 2022 being 45.59%, 95.17%, 77.67% and 80.71% respectively. EV-A71 cases even disappeared. Patients infected with CVA10 had a significantly higher likelihood of hospitalization (P < 0.05), while the presence of oral rash served as a protective factor (P < 0.05).

CONCLUSIONS

Our study highlights the critical need for enhanced surveillance of multiple HFMD pathogens, predominantly caused by the prevalent serotype CVA6. Clinically, enhanced surveillance of CVA10 is imperative to mitigate the hospitalization rate associated with HFMD.

Laboratory Indicators for Identifying Hand, Foot, and Mouth Disease Severity: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study is to study laboratory indicators for the identification of hand, foot, and mouth disease (HFMD) severity.

METHODS

We searched PubMed, Embase, and the Web of Science for literature that was published before May 2022. The main results are presented as forest plots. Subgroup analyses, sensitivity analyses, and publication bias were also performed.

RESULTS

Our study indicated that white blood cells (WBC) (95%CI: 0.205-0.778), blood glucose (95%CI: 0.505-0.778), lymphocytes (95%CI: 0.072-0.239), creatinine (95%CI: 0.024-0.228), interleukin (IL)-2 (95%CI: 0.192-1.642), IL-6 (95%CI: 0.289-0.776), IL-8 (95%CI: 0.499-0.867), IL-10 (95%CI: 0.226-0.930), interferon-γ (IFN-γ) (95%CI: 0.193-2.584), tumor necrosis factor-α (TNF-α) (95%CI: 1.078-2.715), and creatine kinase MB isoenzyme (CK-MB) (95%CI: 0.571-1.459) were associated with an increased risk of HFMD severity, and the results of the sensitivity analysis of these indicators were stable and free of publication bias.

CONCLUSIONS

Our results suggest that various deleterious immune and metabolic changes can increase the risk of HFMD severity, which can provide a basis for predicting the prognosis and useful evidence for clinicians to manage patients efficiently.

Enterovirus 71 VP1 promotes 5-HT release by upregulating the expression of ERICH3 and methyltransferase ZC3H13: VP1 promotes 5-HT release by ERICH3 and ZC3H13 upregulation

BACKGROUND AND AIM

The effect of structural viral protein 1 (VP1) on neurological damage caused by enterovirus 71 (EV71) infection is unclear. This study aimed to explore the transcriptome changes in EV infected patients and the role of VP1 on the cell secretion pathway of neuron cells.

METHODS

In our cohort, EV infected patients were enrolled, and RNA-seq analysis was used to evaluate the distinct transcript patterns of cerebrospinal fluid (CSF). The EV71 VP1-overexpressing vector (pEGFP-c3-VP1) was generated and transfected into neuron cells. The relationship between Glutamate Rich 3 (ERICH3) and methyltransferase Zinc Finger CCCH-Type Containing 13 (ZC3H13) and their effect on the serotonin (5-HT) release of neuron cells were explored using small interfering RNA. The expression of ERICH3 and ZC3H13 and concentration of 5-HT were determined using real-time PCR, Western blot, and ELISA, respectively.

RESULT

The expression of ERICH3 and ZC3H13 were significantly upregulated in EV infected patients with neurological symptoms compared to those without (P<0.05). The ERICH3 gene had many N6-methyladenosine (m6A) binding sites that can be regulated by m6A modification. Further, the expression of ERICH3 and ZC3H13 were elevated significantly in EV71-VP1 overexpressing neuron cells (P<0.05). Moreover, ERICH3 or ZC3H13 deficiency could significantly downregulate the release of 5-HT in VP1-overexpressing cells (P<0.05). Nonetheless, ERICH3 expression was significantly suppressed when ZC3H13 was silenced in neuron cells and vice versa (P<0.05).

CONCLUSIONS

EV71-VP1 can promote 5-HT release by upregulating the expression of ERICH3 and ZC3H13. 5-HT might be a novel therapeutic target for EV71 infection-induced fatal neuronal damage.

Epidemiological characteristics, routine laboratory diagnosis, clinical signs and risk factors for hand, -foot -and -mouth disease: A systematic review and meta-analysis

Background

For the past few years, only a few monovalent EV71 vaccines have been developed, while other enterovirus vaccines are in short supply. We conducted a quantitative meta-analysis to explore the epidemiological characteristics, routine laboratory diagnosis, clinical signs and risk factors for hand, foot and mouth disease (HFMD).

Methods

PubMed, Embase and the Web of Science were searched for eligible reports published before April 16, 2021, with no publication time or language restrictions. The primary outcome was the odds ratio of the epidemiological characteristics, routine laboratory diagnosis, and clinical signs associated with HFMD severity and death.

Results

After screening 10522 records, we included 32 articles comprising 781903 cases of hand, foot and mouth disease. Patients with severe illness developed some clinical signs (hypersomnia (OR = 21.97, 95% CI: 4.13 to 116.74), convulsion (OR = 16.18, 95% CI: 5.30 to 49.39), limb shaking (OR = 47.96, 95% CI: 15.17 to 151.67), and breathlessness (OR = 7.48, 95% CI: 1.90 to 29.40)) and had some changes in laboratory parameters (interleukin-6 levels standardized mean difference (SMD) = 1.57, 95%CI: 0.55 to 2.60), an increased neutrophils ratio (SMD = 0.55, 95%CI: 0.17 to 0.93), cluster of differentiation 4 (CD4+) (SMD = -1.38, 95%CI: -2.33 to -0.43) and a reduced lymphocytes ratio (SMD = -0.48, 95%CI: -0.93 to -0.33)) compared with patients with mild illness. The risk factors for death included cyanosis (OR = 5.82, 95% CI: 2.29 to 14.81), a fast heart rate (OR = 3.22, 95% CI: 1.65 to 6.30), vomiting (OR = 2.70, 95% CI: 1.33 to 5.49) and an increased WBC count (SMD = 0.60, 95% CI: 0.27 to 0.93).

Conclusions

China has the highest incidence of HFMD. Our meta-analyses revealed important risk factors that are associated with the severity and mortality of HFMD.

Prototypes virus of hand, foot and mouth disease infections and severe cases in Gansu, China: a spatial and temporal analysis

Background

Little research has been conducted on the spatio-temporal relationship between the severe cases and the enteroviruses infections of hand, foot and mouth disease (HFMD). This study aimed to investigate epidemic features and spatial clusters of HFMD incidence rates and assess the relationship between Enterovirus 71 (EV71) and Coxsackievirus A16 (CoxA16) and severe cases of HMFD in Gansu province, China.

Methods

Weekly county-specific data on HFMD between 1st January and 31st December 2018 were collected from the China Infectious Disease Information System (CIDIS), including enterovirus type (EV71 and CoxA16), severe and non-severe cases in Gansu province, China. Temporal risk [frequency index (α), duration index (β) and intensity index (γ)] and spatial cluster analysis were used to assess epidemic features and identify high-risk areas for HFMD. Time-series cross-correlation function and regression model were used to explore the relationship between the ratios of two types of viruses (i.e. EV71/Cox16) (EC) and severe cases index (i.e. severe cases/non-severe cases) (SI) of HFMD.

Results

Some counties in Dingxi City, Gansu were identified as a hot spot for the temporal risk indices. Time-series cross-correlation analysis showed that SI was significantly associated with EC (r = 0.417, P < 0.05) over a 4-week time lag. The regression analysis showed that SI was positively associated with EC (β = 0.04, 95% confidence interval (CI) 0.02–0.06).

Conclusion

The spatial patterns of HFMD incidence were associated with enteroviruses in Gansu. The research suggested that the EC could be considered a potential early warning sign for predicting severe cases of HFMD in Gansu province.

Characterization of Enterovirus Associated m6A RNA Methylation in Children With Neurological Symptoms: A Prospective Cohort Study

Little is known about the particular changes of N6-methyladenosine (m6A) RNA methylation in enterovirus (EV) infection among children with neurologic symptoms. Here, we determined the characterization of EV associated m6A RNA methylation in this population. A prospective cohort study was conducted from 2018/2 to 2019/12 at the Guangzhou Women and Children’s Medical Center. We included EV infected children with and without neurological symptoms. High-throughput m(6)A-RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq analysis were used to evaluate the m6A RNA methylation and transcript expression of cerebrospinal fluid samples. The functional annotation and pathways of differentially methylated m6A genes with synchronously differential expression were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Seven patients were enrolled in the control group, and 13 cases were in the neurological symptoms (NS) group. A total of 3472 differentially expressed genes and 957 m6A modified genes were identified. A conjoint analysis of MeRIP-seq and RNA-seq data found 1064 genes with significant changes in both the m6A modifications and mRNA levels. The different m6A RNA methylation was increased in the transcriptome’s CDS regions but decreased in both the 3′UTRs and stop codon among the NS group. Functional annotation like the “oxidative phosphorylation” gene pathway, “Parkinson’s disease” and GO terms like “respiratory electron transport chain,” “cellular metabolic process,” and “oxidation-reduction process” was enriched in symptomatic patients. Our study elucidated the changes of RNA m6A methylation patterns and related cellular functions and signaling pathways in EV patients with neurologic symptoms.

Risk factors of hand, foot, and mouth disease caused by Coxsackievirus A6 in children under 6 years of age in Tianjin, China: a case-control study

Hand, foot, and mouth disease (HFMD) infected with Coxsackievirus A6 (CV-A6) have demonstrated an increasing trend in China. Our study aimed to explore the risk factors of HFMD cases infected with CV-A6 in children under 6 years of age in Tianjin, China. A non-matching case-control study was conducted in Tianjin, China. Cases were HFMD patients infected with CV-A6 while controls were HFMD patients infected with other enteroviruses. Multivariate logistic regression analysis was used to explore the risk factors of HFMD cases infected with CV-A6. A total of 1,264 eligible cases were included in our study, including 589 cases and 675 controls. Our study indicates that the CV-A6 caused HFMD patients were more likely to present with fever and rash on limbs, and home-care children and children having a history of contacting HFMD patient had a high risk of infection with CV-A6, while toy sterilization regularly at home and parents' hand-washing habits after toilet use were the protecting factors for children against CV-A6 infection.

Risk factors for severe hand, foot, and mouth disease infected with Coxsackievirus A6: A hospital-based case-control study

Coxsackievirus 6 (CV-A6) has been emerging as another predominant serotype for severe hand, foot, and mouth disease (HFMD) in China, after the introduction of enterovirus 71 inactivated vaccine (EV71 vaccine) for 3 years. Data on the risk factors for severe HFMD infected with CV-A6 are limited. We interviewed the caregivers to collected data on HFMD patients who sought medical care in the People's Hospital of Baoan district, Shenzhen, from 2015 to 2017. Totally, 131 severe patients were frequency-matched by age and gender with 174 mild patients infected with CV-A6. Univariable and multivariable logistic regression analyses were conducted to analyze the risk factors for severe CV-A6 HFMD. The average age was 20.62 ± 14.18 months and 20.52 ± 12.76 months for severe and mild patients, respectively. Multivariate analyses indicated complications at birth (odds ratio [OR], 4.18; 95% confidence interval [CI]: 1.64-10.63), peak body temperature over 39°C (OR, 4.04; 95% CI: 2.29-7.10) and first-born child (OR, 2.17; 95% CI: 1.27-3.70) increased the risk of severe HFMD infected with CV-A6. Breastfeeding (OR, 0.52; 95% CI: 0.32-0.87), and washing hands after playing frequently (OR, 0.58; 95% CI: 0.34-0.97) were negatively associated with severe illness. Compared with HFMD with infection of EV-A71, complications at birth and first-born child were newly found to be associated with severe illness in HFMD patients infected with CV-A6.

Prognostic Value of Neutrophil-to-Lymphocyte Ratio in Predicting Death Risk in Patients with Severe Hand, Foot and Mouth Disease

Introduction

Severe hand, foot, and mouth disease (HFMD) may lead to serious complications, which cause child mortality during outbreaks. The aim of this study was to determine whether neutrophil-to-lymphocyte ratio (NLR) can predict death risk in severe HFMD.

Methods

Medical records for 664 severe HFMD patients were retrospectively examined, and NLR was calculated from blood counts. Youden’s index was calculated to determine the optimal NLR cutoff. Uni- and multivariate logistic regression were used to determine death risk factors associated with severe HFMD.

Results

An NLR cutoff value of 2.01 and 2.50 respectively predicted mortality among all 664 severe HFMD and 137 critical HFMD. Among all 664 patients, the multivariate model identified the following as independently associated with death risk: high fever (OR 3.342, 95% CI 1.736–6.432), EV71 infection (OR 3.200, 95% CI 1.529–6.698), fasting glucose (OR 37.343, 95% CI 18.616–74.909), and NLR (>2.01) (OR 2.142, 95% CI 1.125–4.079). Among 137 critical HFMD, EV71 infection (OR 3.441, 95% CI 1.132–10.462), fasting glucose (OR 14.173, 95% CI 4.920–40.827), and NLR (>2.50) (OR 4.166, 95% CI 1.570–11.051) were associated with death risk.

Conclusion

In conclusion, NLR (>2.01) in severe HFMD and NLR (>2.50) in critical HFMD patients may be associated with increased death risk.

Epidemiology of Hand, Foot, and Mouth Disease Before and After the Introduction of Enterovirus 71 Vaccines in Chengdu, China, 2009-2018

BACKGROUND

Hand, foot, and mouth disease (HFMD) has posed a serious threat to children's health. Three inactivated monovalent enterovirus 71 (EV71) vaccines are proved to be highly efficacious in phase III clinical trials and are now available in China.

METHODS

We analyzed the citywide surveillance data on HFMD cases in Chengdu during 2009-2018, and estimated cumulative first-dose EV71 vaccination coverage among children eligible to EV71 vaccination after August 2016 in Chengdu. Time series susceptible-infected-recovered model was developed to analyze basic reproduction number and herd immunity threshold of HFMD. Overall and serotype-specific HFMD incidences and severity risks were compared before and after the EV71 vaccination.

RESULTS

Among 3 laboratory-identified serotype categories, i.e. EV71, coxsackievirus A16 (CV-A16), and other enteroviruses, the major serotype attributed to HFMD has been changing across years. The cumulative first-dose EV71 vaccination coverage rate was estimated as 60.8% during the study period in Chengdu. By contrast, herd immunity threshold for EV71-related HFMD was 94.0%. After introduction of EV71 vaccines, the overall incidence of HFMD increased 60.8%, mainly driven by 173.7% and 11.8% increased in HFMD caused by other enteroviruses and CV-A16, respectively, which offset a significant reduction in the incidence of HFMD caused by EV71. The overall case-severity risk decreased from 1.4% to 0.3%, with significantly declined presented in all serotype categories.

CONCLUSIONS

The incidence and severity of EV71-related HFMD decreased following implementation of EV71 vaccination. Developing multivalent vaccines and strengthening laboratory-based surveillance could further decline burden of HFMD.

Interaction between PHB2 and Enterovirus A71 VP1 Induces Autophagy and Affects EV-A71 Infection

Enterovirus A71 (EV-A71) is a major pathogen that causes severe and fatal cases of hand-foot-and-mouth disease (HFMD). HFMD caused by EV-A71 seriously endangers children’s health. Although autophagy is an important antiviral defense mechanism, some viruses have evolved strategies to utilize autophagy to promote self-replication. EV-A71 can utilize autophagy vesicles as replication scaffolds, indicating that EV-A71 infection is closely related to its autophagy induction mechanism. VP1, a structural protein of EV-A71, has been reported to induce autophagy, but the underlying mechanism is still unclear. In this study, we found that the C-terminus (aa 251–297) of VP1 induces autophagy. Mass spectrometry analysis suggested that prohibitin 2 (PHB2) interacts with the C-terminus of the EV-A71 VP1 protein, and this was further verified by coimmunoprecipitation assays. After PHB2 knockdown, EV-A71 replication, viral particle release, and viral protein synthesis were reduced, and autophagy was inhibited. The results suggest that PHB2 interaction with VP1 is essential for induction of autophagy and the infectivity of EV-A71. Furthermore, we confirmed that EV-A71 induced complete autophagy that required autolysosomal acidification, thus affecting EV-A71 infection. In summary, this study revealed that the host protein PHB2 is involved in an autophagy mechanism during EV-A71 infection.

Risk factors for death from hand-foot-mouth disease: a meta-analysis

In recent years, outbreaks of hand–foot–mouth disease (HFMD) in China, Singapore and other Western Pacific Region, involving millions of children, have become a big threat to public health. This study aimed to quantitatively assess all qualified studies and identify the risk factors for HFMD death. A systematic search of the databases PubMed, Medline, Embase and the Cochrane Library was performed. Study heterogeneity and publication bias were estimated. Seven case–control studies involving 1641 participants (634 died and 1007 survived) were included in the meta-analysis. Human enterovirus 71 infection, male, age ⩽3 years, vomiting, cyanosis, convulsion, duration of fever ⩾3 days, atypical rashes and abdominal distention were not significantly related to HFMD death (P ⩽ 0.05). Lethargy (odds ratio (OR) = 6.62; 95% CI 3.61–12.14; I² = 0%; P < 0.0001), pneumonoedema/pneumorrhagia (OR = 4.09; 95% CI 2.44–6.87; I² = 0%; P < 0.0001), seizures (OR = 6.85; 95% CI 2.37–19.74; I² = 0%; P = 0.0004), dyspnoea (OR = 8.24; 95% CI 2.05–33.19; I² = 83%; P = 0.003) and coma (OR = 3.76; 95% CI 1.85–7.67; I² = 0%; P = 0.0003) were significantly associated with HFMD death, which were risk factors for HFMD death.

Effectiveness of enterovirus A71 vaccine in severe hand, foot, and mouth disease cases in Guangxi, China

BACKGROUND

Hand, foot, and mouth disease (HFMD) caused by enterovirus A71 (EV-A71) is a major public health issue in China that poses severe risks to children's health, especially those under the age of 3. Since 2016, EV71 vaccines developed by three Chinese manufacturers have been approved for use, and clinical trials of these vaccines have demonstrated protection against EV-A71 infection. However, few studies have assessed the effectiveness of these vaccines in real-world settings.

METHODS

A test-negative design case-control study was used to estimate vaccine effectiveness (VE) in cases of severe HFMD. We obtained information including EV-A71 vaccination status from the Local Center for Disease Control and Prevention (CDC) on all severe HFMD cases under 12 years in age in Guangxi, China, from Jan. 1, 2017, to Dec. 31, 2018. Enterovirus infection was laboratory confirmed by local CDCs. Individuals with a positive EV-A71 nucleic acid test result were assigned to the case group, and those with negative EV-A71 nucleic acid test results were assigned to the control group. We estimated VE using logistic regression.

RESULTS

A total of 2779 severe HFMD cases were enrolled in the study; 838 children were EV-A71 positive cases, and 1941 children were EV-A71 negative controls. The proportion of EV-A71 positive cases aged 6-36 months was lower than that for EV-A71 negative controls. EV-A71 infection was associated with an increased risk of mortality (aOR, 8.8; 95% CI, 1.3-61.6). The adjusted VE was 81.4% and 88.3% for one dose and two doses, respectively.

CONCLUSION

Our findings suggest that the rate of EV-A71 has fallen among severe HFMD cases in Guangxi and that the risk for EV-A71 infection in 6-36-month-old children has been reduced by use of the vaccine. Inactivated vaccines performed well in severe HFMD cases in a real-world setting.

Developing a Nomogram for Risk Prediction of Severe Hand-Foot-and-Mouth Disease in Children

OBJECTIVE

Early recognition of children with severe Hand-Foot-and-Mouth disease (HFMD) is especially important, as severe cases are associated with poor prognosis. To accomplish this, authors designed a quantitative assessment tool to build a nomogram to assist in clinical diagnosis.

METHODS

A total of 2332 HFMD patients were enrolled in this study; 1750 cases in the mild group and 582 cases in the severe group. Analysis of all of the data was performed using R software version 3.4.3. Multivariate logistic regression was utilized to screen predictors to construct a nomogram model. Finally, predictive performance of the model was evaluated using a receiver operating characteristic (ROC) curve and classifier calibration plot.

RESULTS

A nomogram was constructed with five variables: age, peak temperature, fever duration, pathogen, and vomiting. For the nomogram, the area under the curve was 0.87, and the model prediction accuracy rate was 85.2%. Depending upon the comparison of the area under the ROC curve, the nomogram model was superior to the traditional pediatric clinical illness score (PCIS). With the help of the Hosmer-Lemeshow test and resampling model calibration curve, the fitting performance of the nomogram was stable.

CONCLUSIONS

With advantages such as simplicity, intuitiveness, and practicality, the nomogram (including age, peak temperature, fever duration, pathogen, and vomiting) is capable of predicting severe HFMD and has certain auxiliary value in clinical applications.

Factors associated with severe neurologic complications in patients with either hand-foot-mouth disease or herpangina: A nationwide observational study in South Korea, 2009-2014

BACKGROUND

In 2009, a nationwide sentinel surveillance for hand-foot-mouth disease (HFMD) and herpangina (HA) with neurologic complications was initiated in South Korea. We used this surveillance system to investigate the clinical characteristics of patients with either HFMD or HA with neurologic complications, with the aim of determining risk factors for severe neurologic complications.

METHODS

A retrospective review of medical records was conducted on all cases of HFMD and HA with neurologic complications that were reported in the national system between April 1, 2009 and December 31, 2014. A severe case was defined as having HFMD or HA with encephalitis, polio-like syndrome, or cardiopulmonary failure, and less-severe cases were defined as having HFMD or HA with aseptic meningitis.

RESULTS

A total of 138 cases (less-severe: 90/138, 65.2%; severe: 48/138, 24.8%) were included from 28 hospitals; 28 ineligible cases were excluded. Of 48 severe cases, 27 (56.2%) had encephalitis; 14 (29.2%) had polio-like syndrome; and seven (14.6%) had cardiopulmonary syndrome. The median patient age was 36 months (IQR: 18-60) and 63 (45.7%) patients were female. Most patients completely recovered, except for seven cases that were fatal or resulted in long-term symptoms (5.1%, 3 patients with neurologic sequelae and 4 deaths). In a multivariable logistic regression analysis, lethargy (OR = 4.67, 95% CI: 1.37-15.96, P = 0.014), female sex (OR = 3.51, 95% CI: 1.17-10.50, P = 0.025), and enterovirus A71 (OR = 3.55, 95% CI: 1.09-11.57, P = 0.035) were significantly associated with severe neurologic complications in HFMD and HA patients.

CONCLUSION

In patients with HFMD and HA, lethargy, female, and enterovirus A71 may predict severe neurologic complications.

Mortality in Children with Severe Hand, Foot and Mouth Disease in Guangxi, China

Objective

To analyze the clinical features of children with hand foot and mouth disease (HFMD) who died.

Methods

331 deaths due to HFMD between 2010 and 2014 were included in this retrospective study; 15 autopsies were performed.

Results

Most deaths were seen in children aged below 3 y, and with enterovirus 71 infection (91%). The mean (SD) duration of HFMD from onset to death was 3.7(2.9) d. The mean (SD) age of fast progressors (from onset to death less than 4 days) was 17.4 (9.2) mo. Most of them were diagnosed as stage 3 and stage 4 of HFMD. Various pathological changes were observed in brain after autopsy, especially in brain stem and medulla.

Conclusions

The brain stem encephalitis with the neurotropism of enteroviruses seems to be the main contributor to the death in HFMD.

Machine Learning Algorithms for Risk Prediction of Severe Hand-Foot-Mouth Disease in Children

The identification of indicators for severe HFMD is critical for early prevention and control of the disease. With this goal in mind, 185 severe and 345 mild HFMD cases were assessed. Patient demographics, clinical features, MRI findings, and laboratory test results were collected. Gradient boosting tree (GBT) was then used to determine the relative importance (RI) and interaction effects of the variables. Results indicated that elevated white blood cell (WBC) count > 15 × 10⁹/L (RI: 4⁹.47, p < 0.001) was the top predictor of severe HFMD, followed by spinal cord involvement (RI: 26.62, p < 0.001), spinal nerve roots involvement (RI: 10.34, p < 0.001), hyperglycemia (RI: 3.40, p < 0.001), and brain or spinal meninges involvement (RI: 2.45, p = 0.003). Interactions between elevated WBC count and hyperglycemia (H statistic: 0.231, 95% CI: 0-0.262, p = 0.031), between spinal cord involvement and duration of fever ≥3 days (H statistic: 0.291, 95% CI: 0.035-0.326, p = 0.035), and between brainstem involvement and body temperature (H statistic: 0.313, 95% CI: 0-0.273, p = 0.017) were observed. Therefore, GBT is capable to identify the predictors for severe HFMD and their interaction effects, outperforming conventional regression methods.

Derivation and Validation of a Mortality Risk Score for Severe Hand, Foot and Mouth Disease in China

Outbreaks of hand, foot and mouth disease (HFMD) have increased recently, as has the case fatality rate in severe cases. No scoring system currently exists to predict mortality risk for severe HFMD in previous study. We retrospectively collected laboratory parameters for 546 patients with severe HFMD (a derivation and a validation cohort) at Hunan Children’s Hospitals between January 2012 and December 2014. We developed a mortality risk score comprising four laboratory parameters: blood glucose (GLU), white blood cells (WBC), lactate (LAC), and N-terminal-probrain natriuretic peptide (NT-proBNP). Using an “optimal” cutoff score of 4, the sensitivity, specificity, positive predictive value and negative predictive value was 88.00%, 96.14%, 62.86% and 99.08%, respectively, in the derivation cohort. Among severe HFMD patients with low- and high-risk scores in the validation cohort, case fatality rates were 1.49% and 74.07%, respectively. According to the “optimal” cut-off in the derivation cohort, the sensitivity, specificity, positive predictive value, and negative predictive value were 80.95%, 93.83%, 62.96% and 97.44%, respectively, in the derivation cohort. The mortality risk score demonstrated good discrimination (AUC > 0.9) and calibration (P > 0.05) in both cohorts. The mortality risk score, comprising WBC, GLU, LAC and NT-proBNP, has been demonstrated good discrimination and calibration in the both cohorts.