Study of Serologic Response Rate to Haemophilus influenzae Type B After Administration of the Third Dose of Pentavalent Vaccine in Children Aged 12 Months in Karaj City in 2016

Abstract

Background: Hib conjugate vaccine has led to more than 90% decline in the prevalence of severe Hib diseases in countries with universal coverage vaccination program. After the addition of Hib vaccine to the national vaccination program with 3P (three doses of 2, 4, and 6 months) in IR Iran, we decided to study the vaccine efficacy after the last dose of vaccine in Iranian children in 2016. Methods: 500 blood samples were collected from one-year-old children who referred to the health care centers in Karaj. Demographic information was gathered by a questionnaire. Blood samples were sent to a laboratory for antibody titer determination by ELISA method. Results: 41.2% of the children (95% CI: 36.89-45.51) had a titre of IgG against Hib (0.15 to 1 µg/mL) (short-term protection) and 57.4% of the children had a titre of IgG against Hib (95% CI: 53.07-61.73) equal to or greater than 1 µg/mL (long-term protection). Antibody GMT was 6.92 µg/mL (95% CI: 6.76-7.08). There was no significant correlation between the titer of H. influaenza antibody and demographic factors. Conclusions: In spite of the acceptable GMT titer, children who had antibody titer of < 1 µg/mL comprised approximately 40% of the study population, showing the necessity of further investigation to assess the need for H.flu booster administration.

Immunogenicity and Complications of the Pentavalent Vaccine in Iranian Children

“…This result was similar to the study of (8). In the study of (15) 6 months after the third dose of the Pentavalent vaccine, 17.3% had pertussis immunity (15). In the study of (16) the immunity in two different centers were 36.7 and 24.6% which was lower than our study.…”

“…In the study of (16) the immunity in two different centers were 36.7 and 24.6% which was lower than our study. The reason could be the 6-month interval between the third dose of vaccine and titer measurement in (15) study and the use of different measurement kits (16). The anti-pertussis immunity was higher in some studies which could be due to the younger age of infants and shorter intervals between vaccine doses, antibody assay by microagglutination method, higher sample size and different brands of the vaccine (6,10,(12)(13)(14)17).…”

Immune responses to vaccine-preventable diseases among toddlers and preschool children after primary immunization and first booster in Northwestern Algiers, Algeria

“…Consistent with previous studies [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], the GMTs of IgG-PT were low, significantly higher in children 19–36 months of age: 17.78 IU/ml versus in children 37–55 months of age: 14.79 IU/ml. Twenty-five (25.64%) subjects had titers >25 IU/ml, significantly higher in children 19–36 months of age.…”

“…These data indicates that pertussis antibody levels decrease quickly in young children despite receiving four doses of whole-cell pertussis vaccine. Previous studies explored the low immunity to pertussis with its rapid waning over time and it has been demonstrated that the vaccine-induced antibodies began to wane 1–3 years after pertussis vaccination; children became probably more susceptible to infection at 4 years of age [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Although local epidemiology of pertussis and immunization schedule play a role in the duration of protection following immunization [ 4 , 11 ], it has previously been demonstrated that the immunogenicity of whole-cell pertussis vaccines may differ considerably according to the manufacturer, as there are difficult to produce reproducibly [ 14 , 15 ].…”