Assessment of antibody level and avidity against Bordetella pertussis in a cohort of Egyptian individuals aged 1-18 years

Pertussis specific antibodies were studied with respect to quality and quantity in a cohort of apparently healthy egyptian children and adolescents,with their age range between 1 and 18. years,in an attempt to get a close and clear insight into the current humoral immunization status in this specified group and to try find a relation between the antibody levels and their avidities in eradication of this devastating infectious disease. our results showed that avidity increase was most marked in young school children (6-8 years) where it seemed to reach a plateau in older children and adolescents. antibody titer was highest in toddlers (1-2 years) and young school children (6-8 years) groups,most probably following vaccination and/or booster doses. among children aged 1-5. years,28% had highly avid and 50% had high titer antibodies,whereas in adolescents aged 13-18. years,70% had highly avid antibodies and only 30% had high titer antibodies. the results clearly demonstrated that while levels of anti- bordetella pertussis (b. pertussis) antibodies wane with growing age,the avidity seems to increase,to a plateau,irrespective of further antigen exposure in a pattern showing complete independence of avidity on concentration. the present study draws attention to the importance of avidity measurements,together with conventional elisas,for evaluating immunity against pertussis. being based on a limited sample size,it could open doors for larger-scale surveys to be possible indicators for the need and timing of booster vaccination doses among egyptians. © 2015.