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.

Prevalence of Chronic Hepatitis B Virus Infection among Children in Haiti, 2017.

In 2016, the World Health Assembly endorsed the Global Health Sector Strategy on Viral Hepatitis, which calls for elimination of hepatitis B virus (HBV) by 2030 (definition: ≤ 0.1% hepatitis B surface antigen [HBsAg] prevalence among children aged 5 years). The burden of chronic HBV infection among children in Haiti is unknown. We conducted a nationally representative cross-sectional serological survey among 5- to 7-year-old children based on a two-stage cluster design with two strata: West (includes metropolitan Port-au-Prince) and non-West (all other departments). We collected demographic, socioeconomic, and vaccination history data and tested for HBsAg using a rapid point-of-care test. We estimated HBsAg prevalence and evaluated the association of HBV infection with vaccination history, demographics, and socioeconomic characteristics. Of the 1,152 children, seven (0.5%, 95% CI: 0.2-1.2) were HBsAg positive. The HBsAg prevalence varied by region (West: 0.1%, 95% CI: 0.01-0.9; non-West: 0.7%, 95% CI: 0.2-1.9) (P = 0.1), gender (males: 0.7%, 95% CI: 0.2-2.4; females: 0.2%, 95% CI: 0.05-1.1) (P = 0.3), and caregiver's education level (none: 0.8%, 95% CI: 0.2-3.1; some or completed primary: 0.5%, 95% CI: 0.1-1.8; some secondary: 0.4%, 95% CI: 0.1-1.8; secondary and higher: 0.0%, 95% CI: 0-0), although the differences were not statistically significant. None of the HBsAg-positive children had documented vaccination with hepatitis B vaccine (HepB). Haiti's chronic HBV infection prevalence among children is low; however, it is above the elimination target. To reach elimination, Haiti needs to achieve high coverage with the three HepB doses and introduce a HepB birth dose.