Immunity against Measles in Children Adolescents and Young Adults in the High Urban Refugee Population of Eastleigh in Nairobi, Kenya

Abstract

Kenya has made progress towards elimination of measles through routine and supplementary immunization activities, however, sporadic outbreaks still occur. Studies on measles seroprevalence in Kenya are few and extensive analysis of refugee and migrant populations immunity against measles is lacking. This cross-sectional study aimed at assessing the presence of immunity against measles of children, adolescents and young adults living in high urban refugee area of Eastleigh Nairobi, Kenya. A total of 384 serum samples were collected from consenting respondents and tested for measles immunoglobulin G (IgG) antibodies. Syncytium Inhibition Assay, a neutralization-based assay was used to determine functionality. The establishment of herd immunity was calculated using the Plans- Rubio formulae. Seropositivity was recorded at 84.38% while proportions for negative results were 15.62% respectively. Demographic factors analyzed in this study were not significant predictors of measles antibodies seropositivity. In total, 87.76% of the sera were neutralizing while 12.23 % were negative. There was a significant correlation between the neutralization s and ELISA values. This study highlights age specific measles immunity gaps in an urban refugee population. The critical prevelance for the study population according to Plans-Rubio formulae was 89.99% while the actual prevelance was 84.38%, the population had not established herd immunity. Although measles antibodies are present in all age groups, none had attained herd immunity. In order to avert outbreaks in the study population, it is necessary to direct immunization interventions to increase the measles antibody prevalence to recommended levels.