Evaluating the Effectiveness of a Pneumococcal Immunisation Campaign in a Camp for Internally Displaced People

Evaluating the Effectiveness of a Pneumococcal Immunisation Campaign in a Camp for Internally Displaced People: A Non-randomised, Quasi-experimental Phase IV Intervention Study

Pneumococcal conjugate vaccine (PCV) is used routinely worldwide as part of infant immunisations to prevent acquisition of S. pneumoniae, the aetiologic agent responsible for a large proportion of early childhood pneumonia and invasive disease. However, PCV has seen minimal uptake in populations affected by forced displacement and humanitarian crises, where the burden of pneumococcal disease is plausibly elevated.

This study seeks to generate evidence on appropriate vaccination strategies for crisis-affected populations. The investigators plan to exhaustively vaccinate children aged between six months and four years in a camp for displaced persons outside Hargeisa, the capital of Somaliland. The study will deliver PCV in a campaign modality, so as to achieve both short- and long-term herd immunity effects that, the investigators hypothesise, will reduce population-wide nasopharyngeal S. pneumoniae transmission and thereby protect young children from pneumococcal disease.

The study will adopt a quasi-experimental design, with baseline and post-intervention surveys to evaluate changes in pneumococcal carriage, complemented by safety assessment in children aged over 2 years, who fall outside of the WHO prequalification age range for the vaccine that will be used in this study (i.e. PNEUMOSIL) and for whom PCV safety data are scarce. In addition, we the study will also collect longitudinal data on incidence of pneumonia and antibiotic prescriptions in the camp.

Inclusion Criteria:

1. Resident in Digaale camp
2. Voluntary written/thumb-printed informed consent has been provided by a parent or caregiver
3. Subject's parent/caregiver must be able to comprehend and comply with study requirements and procedures
4. Subject's parents/caregivers must have a readily identifiable place of residence in the study area

Exclusion Criteria:

1. Known hypersensitivity to any component of any of the EPI vaccines, including diphtheria toxoid, in the child or any sibling
2. History of allergic disease or history of a serious reaction to any prior vaccination in the child or any sibling
3. History of anaphylactic shock, regardless of cause
4. History of long-term treatment (defined as 14 or more consecutive days) with immunosuppressants or other immune modifying drugs, including glucocorticoids, but excluding topical and inhaled glucocorticoids