Factors Affecting the Seroconversion Rate of 12-Month-Old Babies after the First Injection of Measles Vaccine in the Southeast of Iran.

Tuesday, 2nd of August 2016

Hum Vaccin Immunother. 2016 Jul 26:0. [Epub ahead of print]

Factors Affecting the Seroconversion Rate of 12-Month-Old Babies after the First Injection of Measles Vaccine in the Southeast of Iran.

Zahraei SM¹ Izadi S² Mokhtari-Azad T³.

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Abstract

Within the past few years several measles outbreaks have occurred in the southeast of Iran. To learn about the effectiveness of the immunization services for producing a serologic response against measles this follow-up study was designed and implemented in the southeast of Iran. In Iran all routine immunization services provided by the public sector are free of charge. The follow-up study was designed and implemented in five Urban Health Centers located in three districts of Sistan-va-Baluchestan Province Iran. In the pre-vaccination phase 270 twelve-month-old babies were blood sampled; and in the post-vaccination phase four to seven weeks after MMR (mump-measles-rubella) vaccination 236 of them were blood sampled (34 dropouts) and their sera were tested for IgG anti-measles antibodies using indirect ELISA in the National Reference Measles Laboratory. Out of the 236 participants who had been blood sampled in the post-vaccination phase 10 (3.7%) were excluded from the calculations of seroconversion rate because they had protective levels of antibody before the vaccination. The seroconversion rate for the remaining 226 participants was 91.2% (95% confidence interval: 86.7 to 94.5). Among the variables studied stunting (height-for-age z-score < -2) showed a strong relationship with the remaining seronegative after the vaccination (odds ratio = 5.6; 95% confidence interval: 1.7 - 18.2). The chance of seroconversion was inversely related to the mothers levels of education (up to nine years of education vs. above nine years) (odds ratio = 0.2; 95% confidence interval: 0.06 - 0.4). In the study population the seroconversion rates for anti-measles antibodies after MMR vaccination are acceptable even though in order to achieve the elimination goal higher standards need to be achieved