Long-Term Immunogenicity Study of an Aluminum Phosphate-Adjuvanted Inactivated Enterovirus A71 Vaccine in Children: An Extension to a Phase 2 Study.
Journal
Vaccines
Journal Volume
12
Journal Issue
9
ISSN
2076-393X
Date Issued
2024-08-29
Author(s)
Chiu, Nan-Chang
Lin, Chien-Yu
Chen, Charles
Cheng, Hao-Yuan
Hsieh, Erh-Fang
Liu, Luke Tzu-Chi
Chiu, Cheng-Hsun
Abstract
Enterovirus A71 (EV-A71) causes hand, foot, and mouth disease in infants and children with potential for fatal complications such as encephalitis and acute flaccid myelitis. This study examined the long-term immunity conferred by EV71vac, an inactivated EV-A71 vaccine adjuvanted with aluminum phosphate, in children from the age of 2 months to <6 years, for up to 5 years after the first immunization. A total of 227 participants between 2 months and <6 years of age who had previously received either EV71vac or placebo in the phase two clinical study were enrolled. Subjects were divided into age groups: 2 years to <6 years (Group 2b), 6 months to <2 years (Group 2c), and 2 months to <6 months (Group 2d). At Year 5, the neutralizing antibody titers against the B4 subgenotype remained high at 621.38 to 978.20, 841.40 to 1159.93, and 477.71 to 745.07 for Groups 2b, 2c, and 2d, respectively. Cross-neutralizing titers at Year 5 remained high against B5 and C4a subgenotypes, respectively. No long-term safety issues were reported. Our study provides novel insights into the long-term immunity conferred by EV71vac in children aged from two months to six years, particularly in those who received EV71vac between two and six months of age.
Subjects
EV-A71
EV-A71 vaccine
clinical trial
enterovirus
enterovirus vaccine
hand, foot and mouth disease
immune durability
pediatrics
SDGs
Type
journal article