The following document is the summary of enterovirus surveillance updates from the APNES webinar meeting held on May 24, 2022.
Due to COVID-19, the 2022 APNES annual conference were held online on the 24th May 2022. All APNES members and researchers from Malaysia, Vietnam, Thailand, Cambodia, Taipei and Bangladesh have attended, making it a fruitful and successful webinar.
On November 4, 2021, APNES held the “Memorandum of Understanding (MOU) signing” ceremony.
Welcoming the new APNES member: University Medical Shing Mark Hospital in Vietnam.
Taiwan Association For Vaccine Industry (TAVI)
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Tzu-Yu Weng, Hua Yen, Kutub Mahmood, Javier Martin, and Min-Shi Lee
National Health Research Institutes, Zhunan, Taiwan (T.-Y. Weng, H. Yen, M.-S. Lee); Center for Vaccine Innovation and Access, PATH, Seattle, Washington, USA (K. Mahmood); National Institute for Biological Standard and Control, Potters Bar, UK (J. Martin)
The Asia-Pacific Network for Enterovirus Surveillance in the National Health Research Institutes hosted a workshop on May 2, 2019, to discuss the harmonization of 2 licensed enterovirus vaccines, poliovirus and enterovirus A71 (EV-A71), especially regarding the standardization of vaccine antigens (Appendix). Speakers from the UK National Institute for Biologic Standard and Control (NIBSC), US PATH, industries, and regulatory agencies shared their experiences.
Sabin strain–derived live-attenuated oral poliovirus vaccines (OPV) and wild strain–derived inactivated poliovirus vaccines (IPV) have been widely used. Since wild-type 2 poliovirus was eradicated, bivalent OPV (only type 1 and 3) replaced trivalent OPV. Wild-type 3 is almost eradicated, and major efforts are under way to eradicate type 1. In addition, wild strains are not feasible to produce conventional IPV (cIPV) after wild polioviruses are eradicated. Therefore, the World Health Organization (WHO) recommends the development of Sabin strain–derived IPV (sIPV) for the endgame plan of global poliovirus eradication programs. Because WHO international standard (IS) antigen for quantifying cIPV antigens could not be effectively used to quantify sIPV, new reagents based on sIPV need to be established.
Three EV-A71 vaccines have been licensed in China, and 2 EV-A71 vaccine candidates were evaluated in phase III trials in Taiwan. Experience with IPV indicates that establishing WHO IS antigens is critical for global harmonization of EV-A71 vaccines. Thus, NIBSC and the China National Institute of Food and Drug Control (NIFDC) coordinated an international study for the first IS antigen of EV-A71 vaccines. Some participants in the international study shared their results in the workshop. This report summarizes outcomes of presentations and discussion.
Enteroviruses (EV), the major pathogens of hand, foot, and mouth disease (HFMD) and herpangina, affectmillions of children each year. Most human enteroviruses cause self-limited infections except polio-viruses, enterovirus A71 (EV-A71), enterovirus D68 (EV-D68), and several echoviruses (Echo) and cox-sackieviruses (CV). Especially, EV-A71 has repeatedly caused large-scale outbreaks in the Asia-Pacificregion since 1997. Some Asian countries have experienced cyclical outbreaks of severe EV-A71 infectionsand initiated development of EV-A71 vaccines. Five EV-A71 vaccine candidates have been clinically eval-uated and three of them were approved for marketing in China.
Li-Min Huang, Cheng-Hsun Chiu, Nan-Chang Chiu, Chien-Yu Lin, Ming-Ta Li, Tsun-Yung Kuo, Yi-Jen Weng, Erh-Fang Hsieh, I-Chen Tai
Background: To ﬁght against enterovirus A71 (EV-A71)-associated diseases, initiated in Taiwan focusing on two-month-old infants.
Methods: We conducted a phase II, double-blind, randomised, placebo-controlled study on infants and children aged two months to 11 years. This study was conducted in 4 parts (2a, 2b, 2c, and 2d) with age de-escalation sequentially. Two doses were administered with a 28-day or 56-day interval. Participants aged two months to (<)two years received a booster dose at one year after the ﬁrst dose. During the surveillance period, solicited adverse events (AEs) and unsolicited AEs were recorded for safety evaluation. Blood samples were collected for neutralising antibody assay at various times. Immune persistence and booster effects were also assessed.
Results: A total of 363 children completed the study. Most AEs were mild and unrelated to treatment. No vaccine-related serious adverse events (SAEs) were reported. Geometric mean titres (GMTs) of serum neutralising antibody titres increased profoundly. Most participants in the vaccine groups achieved deﬁned seroprotection (neutralization titre 1:32) after the second vaccination and persisted for two years. Furthermore, the EV-A71 vaccine could provide a cross-reaction against other EV-A71 strain geno-types: B5, C4a, C4b, and C5.
Conclusions: The mid dose of the EV-A71 vaccine elicited high immune response and were tolerable in participants aged between two months and 11 years in all dosing groups.
Sourced from Medigen Vaccine Corporation, Taiwan