Seroconversion rate following measles vaccination.

ABSTRACT

OBJECTIVE: To assess the seroconversion rate following measles vaccination in Sri Lankan children. DESIGN: A descriptive study. SETTING: Immunisation clinic, Lady Ridgeway Hospital, Colombo (LRHC). SUBJECTS: 134 infants who attended the LRHC for measles vaccination. MEASUREMENTS Pre- and post-vaccination blood samples were collected and serum was tested for the presence of anti-measles 1gG antibodies using the ELISA technique. RESULTS: Of the 134 infants only 102 were brought for the post-vaccination sample. Of these 102 samples, 101 were negative for anti-measles antibodies before vaccination. Of the 101 sero-negative samples 94 became sero-positive 6 to 8 weeks after vaccination. These results indicate that the seroconversion rate is 93.06%, which is similar to the results of studies done in other countries. CONCLUSION: Most infants are susceptible to measles infection by the age of 9 months, and it is appropriate to vaccinate infants at this age, as is the practice at present. However, further studies are needed to assess the duration of protection with a single dose of measles vaccine.