Seroprevalence of Measles, Rubella, Tetanus, and Diphtheria Antibodies among Children in Haiti, 2017.

In Haiti, measles, rubella, and maternal and neonatal tetanus have been eliminated, but a diphtheria outbreak is ongoing as of 2019. We conducted a nationally representative, household-based, two-stage cluster survey among children aged 5-7 years in 2017 to assess progress toward maintenance of control and elimination of selected vaccine-preventable diseases (VPDs). We stratified Haiti into West region (West department, including the capital city) and non-West region (all other departments). We obtained vaccination history and dried blood spots, and measured antibody concentrations to VPDs on a multiplex bead assay. Among 1,146 children, national seropositivity was 83% (95% CI: 80-86%) for tetanus, 83% (95% CI: 81-85%) for diphtheria, 87% (95% CI: 85-89%) for measles, and 84% (95% CI: 81-87%) for rubella. None of the children had long-term immunity to tetanus or diphtheria (IgG concentration ≥ 1 international unit/mL). Seropositivity in the West region was lower than that in the non-West region. Vaccination coverage was 68% (95% CI: 61-74%) for ≥ 3 doses of tetanus- and diphtheria-containing vaccine (DTP3), 84% (95% CI: 80-87%) for one dose of measles-rubella vaccine (MR1), and 20% (95% CI: 16-24%) for MR2. The seroprevalence of measles, rubella, and diphtheria antibodies is lower than population immunity levels needed to prevent disease transmission, particularly in the West region; reintroduction of these diseases could lead to an outbreak. To maintain VPD control and elimination, Haiti should achieve DTP3 and MR2 coverage ≥ 95%, and include tetanus and diphtheria booster doses in the routine immunization schedule.