Enteroviruses (EV) are the major pathogens of Hand, Foot, and Mouth Disease (HFMD), affect millions of people each year worldwide, especially among infants and young children. Enterovirus 71 (EV71) is the most fatal form of Enteroviruses, repeatedly caused large outbreaks of HFMD in the Asia-Pacific region.
In Taiwan, the largest nationwide EV71 epidemic occurred in 1998. There were at least 405 children hospitalized and 78 died with serious neurological complications. A total of 130,000 cases of HFMD and herpangina were reported to the national sentinel surveillance program. It has been estimated that 1.5 million cases of HFMD occurred during the epidemic.
The rapid progression of severe complications, such as central nervous system disease and cardiopulmonary failure, can lead to death within 24 to 48 hours. Based on health economic studies, each EV case may cost medical expenses around $69-771 USD. Moreover, children with EV infections may need to stay at home for 1 week in some countries, which indirectly brings huge impacts on the society mainly attributable to parental miss from works.
In addition to Taiwan, EV71 also caused severe epidemics in several Asian Countries, including Brunei, Cambodia, China, Malaysia, Singapore, and Vietnam. As well as in Cambodia, the largest outbreak of EV71 infection was in 2012, which killed at least 54 children. In Malaysia, the first large outbreak of EV71-associated HFMD emerged in 1997 and caused 41 deaths among young children. In Vietnam, the largest outbreak of HFMD during 2011-2012 caused over 200,000 hospitalizations and 207 deaths. However, enterovirus infection is a very serious problem in Cambodia, Malaysia, Vietnam and Taiwan and we need to work together to control and prevent it.
Vaccination would be the best strategy to prevent EV71 infections. EV71 vaccines have been licensed recently in China but they are not available outside China. Therefore, other Asian countries with EV71 epidemics should work together to speed up development of EV71 vaccines. Especially, longitudinal surveillance data and multi-national clinical trials are critical for vaccine development. A global enterovirus surveillance network is urgently needed to monitor the epidemics, virus evolution, and immune responses to vaccines for enteroviruses.
Although WHO Western Pacific Regional Office (WPRO) has established a HFMD surveillance system since 2011, its reporting system has some limitations: First, the data format is not consistent. Second, the surveillance data only include China, Hong Kong, Japan, Korea, Macao, Singapore and Vietnam, but not Cambodia, Malaysia, and Taiwan. Third, the online biweekly report does not include laboratory diagnosis and EV serotyping, so it is not helpful to understand epidemiology of different EV serotypes. Therefore, an enterovirus surveillance system integrating clinical and virological data is urgently needed in Asian countries facing EV71 epidemics.
In response to this unmet medical needs, the Asia-Pacific Network for Enterovirus Surveillance (APNES) was established through collaborations between academic institutes and hospitals in Cambodia, Malaysia, Vietnam and Taiwan. In the first phase, the members of APNES include the Institut Pasteur du Cambodge (IPC) in Cambodia, University of Malaya (UM) and Universiti Malaysia Sarawak (UNIMAS) in Malaysia, the Children’s Hospital No. 1 of Ho Chi Minh City (CH1-HCMC) and the Pasteur Institute of Ho Chi Minh City (PI-HCMC) in Vietnam, and Taiwan NHRI. All APNES members agree to share surveillance data and reagents.