Vaccine coverage and timeliness among children of adolescent mothers: A community-based study in the Eastern Cape, South Africa.

Background: Children born to adolescent mothers are more vulnerable to infant mortality and morbidity than those born to adult mothers. HIV-exposed children have lower antibody protection against vaccine-preventable diseases at birth compared to unexposed children. In South Africa, 17 % of adolescent girls aged 15-19 years are mothers, yet vaccination coverage and timeliness among their children is underreported.
Methods: This study estimated age-appropriate vaccination coverage and timeliness among children (n = 1080) of adolescent mothers (n = 1015) in the Eastern Cape, South Africa. Mother-child dyads were recruited through healthcare and community-based sampling strategies. Vaccination data were abstracted from 1013 home-based child health records (2017-2019). Coverage is reported for Diphtheria-Tetanus-Pertussis 3rd dose (DTP3), under-1 vaccination among children over 12 months (n = 613) and measles 2nd dose (MCV2) among children over 24 months (n = 382) using proportions with 95 % confidence intervals (95 %CI). Timeliness is defined as receiving each vaccination within 4 weeks of recommended age. Findings are disaggregated by maternal HIV-status.
Results: Overall, 27.3 % of adolescent mothers were living with HIV. Coverage of DTP3 was 85.6 % (95 %CI: 82.6-88.3 %), under-1 coverage was 53.2 % (95 %CI: 49.1-57.2 %), and MCV2 coverage was 62.3 % (95 %CI: 57.2-67.2 %). Vaccination coverage was lower among children of adolescent mothers living with HIV (AMLHIV) than unexposed children (DTP3 80.3 % vs 88.2 % p-value: 0.01; under-1 46.5 % vs 56.4 % p-value: 0.02; MCV2 55.4 % vs 67.1 % p-value: 0.02). Timeliness of vaccinations declined over time from 98.0 % at birth, 70.7 % at 14 weeks, 71.9 % at 9 months and 37.3 % at 18 months.
Conclusion: Vaccination coverage among children of adolescent mothers in the Eastern Cape are below national targets. Children of AMLHIV had lower coverage than HIV-unexposed children. Further research is needed to identify risk factors associated with incomplete and delayed vaccinations among this group, particularly among HIV-exposed children. Enhanced vaccination campaigns may be required for children of adolescent mothers.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Camille Wittesaele reports financial support was provided by Horowitz Foundation for Social Policy. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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