Hand, foot, and mouth disease (HFMD) is a common viral illness in infants and children caused by viruses that belong to the enterovirus genus of the picornavirus family. Although most HFMD cases do not result in serious complications, outbreaks of HFMD caused by enterovirus 71 (EV71) can present with a high rate of neurological complications, including meningoencephalitis, pulmonary complications, and can even cause infant death. HFMD caused by EV71 has become a major emerging infectious disease in Asia and the highly pathogenic potential of EV71 clearly requires the attention of world medical community. The phase II study of inactivated vaccine (vero cell) against EV71 has completed last month in Jiangsu Province in China. The data from the phase II study suggested that the inactivated EV71 vaccine had a clinically acceptable safety and good immunogenicity for healthy Chinese children and infants. But the antibody titer against EV71 was found decreased significantly at month 8 compared to that at day 56. Considering the similar dynamic trend had also been found in the antibody against poliovirus induced by polio vaccines, and whose immunization schedule contains a booster dose administrated at 1 to 1.5 year after the first 3 doses of fundamental immunity. In order to find a better immunization schedule for children, the investigators decided to perform this booster immunity trial among these children who had received two doses of EV71 vaccines (around one year after the fundamental immunity). The investigators do the recruitment among these children who had participated in the previous phase II trial and received EV71 vaccines, and randomize them in a ratio of 2:1 to receive either a booster dose of EV71 vaccines or placebo.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
773
inactivated vaccine (vero cell) alum-adjuvant 160U /0.5ml EV71 vaccine
inactivated vaccine (vero cell) alum-adjuvant 320U /0.5ml EV71 vaccine
inactivated vaccine (vero cell) alum-adjuvant 640U /0.5ml EV71 vaccine
inactivated vaccine (vero cell) adjuvant-free 640U /0.5ml EV71 vaccine
0/0.5ml placebo
Jiangsu Provincial Center for Diseases Control and Prevention
Nanjing, Jiangsu, China
Geometric mean titer (GMT) of anti-EV71 antibodies
GMT of anti-EV71 antibodies in serum 28 days after booster dose injection
Time frame: 28 days after vaccination
Safety of EV71 vaccine in healthy children
Frequency of systemic and local adverse reactions in healthy children following 28 days after the boosting dose of EV71 vaccine
Time frame: 28 days after vaccination
Geometric mean fold increase (GMFI) of anti-EV71 antibodies
GMFI of anti-EV71 antibodies in serum 28 days after vaccination
Time frame: 28 days after vaccination
Seroconversion of anti-EV71 antibodies
Seroconversion of anti-EV71 antibodies in serum 28 days after vaccination
Time frame: 28 days after vaccination
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