Diversity of Human Enterovirus Co-Circulations in Five Kindergartens in Bangkok between July 2019 and January 2020.

Human enterovirus causes various clinical manifestations in the form of rashes, febrile illness, flu-like illness, uveitis, hand-foot-mouth disease (HFMD), herpangina, meningitis, and encephalitis. Enterovirus A71 and coxsackievirus are significant causes of epidemic HFMD worldwide, especially in children aged from birth to five years old. The enterovirus genotype variants causing HFMD epidemics have been reported increasingly worldwide in the last decade. We aim to use simple and robust molecular tools to investigate human enteroviruses circulating among kindergarten students at genotype and subgenotype levels. With the partial 5'-UTR sequencing analysis as a low-resolution preliminary grouping tool, ten enterovirus A71 (EV-A71) and coxsackievirus clusters were identified among 18 symptomatic cases and 14 asymptomatic cases in five kindergartens in Bangkok, Thailand, between July 2019 and January 2020. Two occurrences of a single clone causing an infection cluster were identified (EV-A71 C1-like subgenotype and coxsackievirus A6). Random amplification-based sequencing using MinION (Oxford Nanopore Technology) helped identify viral transmission between two closely related clones. Diverse genotypes co-circulating among children in kindergartens are reservoirs for new genotype variants emerging, which might be more virulent or better at immune escape. Surveillance of highly contagious enterovirus in communities is essential for disease notifications and controls.

Clinical analysis of 8 cases of neonatal hand-foot-mouth disease / 临床儿科杂志

Objective To study the clinical features,treatment and prognosis of neonatal hand-foot-mouth disease.Methods Neonatal hand-foot-mouth disease patients admitted from July 2014 to May 2016 were retrospectively studied.EV71,CA16 and universal enterovirus were detected from newborn swabs by RT-PCR.Results A total of 8 neonatal patients with hand-foot-mouth diseases,6 boys and 2 girls were diagnosed at an age ranged from 7-26 days.Of them,7 patients had exposure history.Clinical manifestations including rash (8 cases),fever (6 cases),irritability (4 cases) and vomiting (1 case),nobody suffered convulsions.The results of RT-PCR showed pathogen enterovirus not-EV71 and not-CA16.There were 5 cases of pulmonary infection treated with antibiotic therapy.All of the 8 cases had a good prognosis.Conclusions Most of the handfoot-mouth diseases had exposure history without specific clinical manifestations.They had not-EV71 and not-CA16 intestinal virus infection,some patients had pulmonary infection.Therefore,neonatal hand-foot-mouth diseases need more clinical attention.

Progress on the research and development of inactivated EV71 whole-virus vaccines.

The prevalence of diseases caused by EV71 infection has become a serious public health problem in the Western Pacific region. Due to a lack of effective treatment options, controlling EV71 epidemics has mainly focused on the research and development (R&D) of EV71 vaccines. Thus far, five organizations have completed pre-clinical studies focused on the development of inactivated EV71 whole-virus vaccines, including vaccine strain screening, process optimization, safety and immunogenicity evaluation, and are in different stages of clinical trials. Among these organizations, three companies in Mainland China [Beijing Vigoo Biological Co., Ltd. (Vigoo), Sinovac Biotech Ltd. (Sinovac) and Institute of Medical Biology, Chinese Academy of Medical Science (CAMS)] have recently completed Phase III trials for the vaccines they developed. In addition, the other two vaccines, developed by National Health Research Institutes (NHRI) of Taiwan and Inviragen Pte., Ltd (Inviragen), of Singapore, have also completed Phase I clinical trials. Published clinical trial results indicate that the inactivated EV71 vaccines have good safety and immunogenicity in the target population (infants) and confer a relatively high rate of protection against EV71 infection-related diseases. The results of clinical trials suggest a promising future for the clinical use of EV71 vaccines. Here, we review and highlight the recent progress on the R&D of inactivated EV71 whole-virus vaccines.

Production of EV71 vaccine candidates.

Enterovirus 71 (EV71) is now recognized as an emerging neurotropic virus in Asia and with Coxsackie virus (CV) it is the other major causative agent of hand-foot-mouth diseases (HFMD). Effective medications and/or prophylactic vaccines against HFMD are urgently needed. From a scientific (the feasibility of bioprocess, immunological responses and potency in animal challenge model) and business development (cost of goods) points of view, we in this review address and discuss the pros and cons of different EV71 vaccine candidates that have been produced and evaluated in animal models. Epitope-based synthetic peptide vaccine candidates containing residues 211-225 of VP1 formulated with Freund's adjuvant (CFA/IFA) elicited low EV71 virus neutralizing antibody responses, but were protective in the suckling mouse challenge model. Among recombinant EV71 subunits (rVP1, rVP2 and rVP3) expressed in E. coli, purified and formulated with CFA/IFA, only VP1 elicited mouse antibody responses with measurable EV71-specific virus neutralization titers. Immunization of mice with either a DNA plasmid containing VP1 gene or VP1 expressed in Salmonella typhimurium also generated neutralizing antibody responses and protected animals against a live EV71 challenge. Recombinant EV71 virus-like particles (rVLP) produced from baculovirus formulated either with CFA/IFA or alum elicited good virus neutralization titers in both mice and non-human primates, and were found to be protective in the suckling mouse EV71 challenge model. Synthetic peptides or recombinant EV71 subunit vaccines (rVP1 and rVLP) formulated in alum were found to be poorly immunogenic in rabbits. Only formalin-inactivated (FI) EV71 virions formulated in alum elicited cross-neutralizing antibodies against different EV71 genotypes in mice, rabbits and non-human primates but induced weak neutralizing responses against CAV16. From a regulatory, economic and market acceptability standpoint, FI-EV71 virion vaccines are the most promising candidates and are currently being evaluated in human clinical trials. We further describe and analyze some new bioprocesses technologies that have great potential applications in EV71 vaccine development. This review also demonstrates the opportunities and challenges that the Asian vaccine industry faces today.