Reduced vaccination and the risk of measles and other childhood infections post-Ebola

Abstract

The Ebola epidemic in West Africa has caused substantial morbidity and mortality. The outbreak has also disrupted health care services, including childhood vaccinations, creating a second public health crisis. We project that after 6 to 18 months of disruptions, a large connected cluster of children unvaccinated for measles will accumulate across Guinea, Liberia, and Sierra Leone. This pool of susceptibility increases the expected size of a regional measles outbreak from 127,000 to 227,000 cases after 18 months, resulting in 2000 to 16,000 additional deaths (comparable to the numbers of Ebola deaths reported thus far). There is a clear path to avoiding outbreaks of childhood vaccine-preventable diseases once the threat of Ebola begins to recede: an aggressive regional vaccination campaign aimed at age groups left unprotected because of health care disruptions.

Figure 1

Number of children 9 to 59 months of age not vaccinated against measles in Guinea, Liberia, and Sierra Leone (A) before disruptions in vaccination due to Ebola, (B) after 6 months of a 75% reduction in measles vaccination rates nationally due to Ebola related health care disruptions, (C) after 12 months of disruptions, and (D) after 18 months of disruptions with numbers of unvaccinated children (without disruptions) in neighboring countries shown.

Figure 2

The left panel of each figure indicates the history of routine vaccination (light blue squares, size indicates coverage) and SIA campaigns (dark blue squares) for each age cohort by year in (A) Guinea, (B) Liberia, and (C) Sierra Leone. The right panel indicates the projected number susceptible to measles in each age cohort from 0 to 40 years of age: projected 2015 age distribution of measles susceptibility if no Ebola related disruptions to vaccination occurred (green) and after 18 months of Ebola related health care disruptions (red).