[Study on the subclinical infection of the recipients of measles vaccine].

Through observation to subclinical infection of the 71 children who had been inoculated against measles 12 years ago and then exposed to natural measles from three classes at a primary school, we have noticed: (1) Subclinical infection did exist among the crowd who were inoculation against measles; The rate of subclinical infection of the three classes was between 18.5%-75.0%, with an average of 45.1%. (2) The level of the HI Ab titer was between 1:2-1:16. The peak level was between 1:2 and/or 1:4. So the rate of subclinical infection who had been inoculation against measles but later exposed to natural measles would depend on the proportion of those whose titer of HI Ab was 1:2-1:4 in the crowd. (3) The epidemiological significance of subclinical measles infection lies in that it can actively keep and consolidate the level of immunity to certain extent in a crowd who had been inoculation against measles.