Field Studies of Protection from Infection by Experimental Trachoma Virus Vaccine in Preschool-Aged Children on Taiwan.

Summary Field trials of experimental egg-grown trachoma virus vaccine have been carried out in preschool-aged children in 2 rural areas on Taiwan. Four hundred and five children randomly divided between a placebo and trachoma vaccine groups have been followed for 2 1/2 years during which 4 injections of vaccine have been given. Eighteen per cent of the placebo group have converted to trachoma compared to 8% of those receiving vaccine. An average of 2.98 months of trachoma have been observed in the placebo group compared to 1.22 months in the vaccine group. Both these measures suggested that the vaccine was approximately 60% effective in reducing trachoma. A third study in an urban area with 89 children showed similar vaccine effectiveness.