Vaccination Coverage and Risk Factors Associated With Incomplete Vaccination Among Children in Cambodia, Madagascar, and Senegal.

Background: Vaccination reduces mortality from infectious disease, which is the leading cause of death in children under 5 and bears a particularly high burden in low- and middle-income countries. The Global Vaccine Action Plan (2011-2020) has set a target of 90% vaccine coverage for all vaccines included in national immunization programs by 2020. The objectives of this study were to estimate vaccine coverage among children in Madagascar, Cambodia, and Senegal and to identify the risk factors associated with incomplete vaccination. Methods: Using data from a community-based prospective cohort that included all newborn of some areas from 2012 to 2018 in these 3 countries, vaccine coverage was estimated for BCG, hepatitis B, oral polio, pentavalent (targeting diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b), and measles vaccines. Risk factor analysis was performed with logistic regression models to identify correlates of incomplete vaccination. Results: A total of 3606 children were followed up, and vaccine coverage was below the 90% threshold for most vaccines in all countries. Coverage was higher for vaccines recommended at birth and at 6 weeks, while a decrease in coverage for subsequent doses was observed for vaccines requiring several doses (23-47 points). Low birth weight (<2500 g) was an important risk factor for nonvaccination for vaccines recommended at birth in all 3 countries (adjusted odds ratio [95% confidence interval] ranging from 1.93 [1.11-3.38] to 4.28 [1.85-9.37]). Conclusions: Vaccine coverage for common childhood vaccines was lower than World Health Organization recommendations, and multidisciplinary approaches may help to improve vaccine coverage and timeliness.

Excess risk of subsequent infection in hospitalized children from a community cohort study in Cambodia and Madagascar.

BACKGROUND: Children in low- and middle-income countries are particularly vulnerable in the months following an initial health event (IHE), with increased risk of mortality caused mostly by infectious diseases. Due to exposure to a wide range of environmental stressors, hospitalization in itself might increase child vulnerability at discharge. The goal of this study was to disentangle the role of hospitalization on the risk of subsequent infection. METHODS: Data from a prospective, longitudinal, international, multicenter mother-and-child cohort were analysed. The main outcome assessed was the risk of subsequent infection within 3 months of initial care at hospital or primary healthcare facilities. First, risk factors for being hospitalized for the IHE (Step 1) and for having a subsequent infection (Step 2) were identified. Then, inpatients were matched with outpatients using propensity scores, considering the risk factors identified in Step 1. Finally, adjusted on the risk factors identified in Step 2, Cox regression models were performed on the matched data set to estimate the effect of hospitalization at the IHE on the risk of subsequent infection. RESULTS: Among the 1312 children presenting an IHE, 210 (16%) had a subsequent infection, mainly lower-respiratory infections. Although hospitalization did not increase the risk of subsequent diarrhoea or unspecified sepsis, inpatients were 1.7 (95% Confidence Intervals [1.0-2.8]) times more likely to develop a subsequent lower-respiratory infection than comparable outpatients. CONCLUSION: For the first time, our findings suggest that hospitalization might increase the risk of subsequent lower-respiratory infection adjusted on severity and symptoms at IHE. This highlights the need for robust longitudinal follow-up of at-risk children and the importance of investigating underlying mechanisms driving vulnerability to infection.