بررسي شكست اوليه و ثانويه واكسيناسيون سرخك در شهر مشهد 80-1379

Evaluation of Primary and Secondary Failures o/Measles Vaccination in 15-19 Years Old Individuals in Mashhad

Immune status of the community to measles virus may be low due to inadequate coverage of vaccination or vaccine failure. This study evaluates the primary and secondary measles vaccine failures in seronegative individuals. For this purpose 50 students from a previous study were selected. These students were 15-19 yrs old and in all of them serum anti-measles lgG level were below 30 IU/ml. One dose of measles vaccine was injected subcutaneously to all of these students and after 4 wk, their serum specimens were obtained and tested for measles specific lgG and lgM antibodies by ELISA method. lgG and lgM were reported as quantitative and qualitative results, respectively. lgM antibodies for measles were found in 12 (24%) individuals. The remaining 38 (76%) cases were lgM seronegative. lgG antibodies for measles were found in 48 (96%) serums, and two other serums did not have lgG anti-measles antibodies. Primary vaccine failure was observed in 12 (24%) and secondary vaccine failure in 36(72%) cases. Two (4%) individuals were non-responders. The highest percentages of primary vaccine failures were in the range of 17-17.9 yrs old. However, the highest percentages of secondary vaccine failures were in the range of 19-19.9 yrs old. Similarly, no correlation was observed between socioeconomic status of individuals and primary or secondary vaccine failure. The above mentioned highest percentages of cases showing primary and secondary failures had been vaccinated in years 1364-65 and 1362-63 respectively. Primary and secondary failures in vaccination for measles, as shown in this study, suggest a need for re-vaccination program for high-risk individuals.