BEIJING, March 14, 2013 /PRNewswire/ -- Sinovac Biotech Ltd. (NASDAQ: SVA), a leading provider of vaccines in China, announced today preliminary top-line data from its Phase III clinical trial assessing the efficacy, immunogenicity and safety of the Company's proprietary Enterovirus 71 ("EV71") vaccine against hand, foot and mouth disease ("HFMD"). The primary objective of the study was to evaluate the efficacy of the EV71 vaccine in the prevention of HFMD caused by EV71 in infants of 6 to 35 months old. The preliminary Phase III data showed that Sinovac's EV71 vaccine was 95.4% (95% CI: 87.5%, 98.3%) efficacious against HFMD caused by EV71. The Phase III trial showed good immunogenicity and safety for Sinovac's EV71 vaccine. The overall incidence of serious adverse events in this trial was 2.2% among the EV71 candidate vaccine recipients and 2.6% among those receiving a control vaccine during the fourteen months observation period. The difference in rates of serious adverse events ("SAEs") is not statistically significant. Most of the SAEs were considered unlikely to be vaccine-related. The double-blinded, randomized, placebo controlled Phase III clinical trial was conducted at three sites across China's Jiangsu province. Approximately 10,000 healthy infants completed the two dose vaccination schedule (at 0 and 28 days) in the first quarter of 2012, prior to the HFMD epidemic season in China, followed by active monitoring period. In parallel, Sinovac conducted another clinical study that was comprised of 1,400 volunteers and designed to evaluate the consistency of three consecutive lots of EV71 vaccine manufactured by the Company. The trial was conducted in children from 6 month to 5 years old. After receiving the vaccine, the ratios of neutralizing antibody GMTs on the 56th day of any two groups were calculated and the 95% confidence intervals of the ratios are all between 0.67 and1.5, which indicates the immunogenicity of the three vaccine lots is equivalent. The study results showed consistent immune response for all three lots and a good safety profile. With immunogenicity equivalent across the three consecutive lots, the results showed Sinovac's vaccine production process and quality are stable.