Browsing by Author "Pienaar, Elizabeth"

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    A global bibliometric analysis of research productivity on vaccine hesitancy from 1974 to 2019
    (Taylor & Francis, 2021-05) Jaca, Anelisa; Iwu-Jaja, Chinwe J.; Balakrishna, Yusentha; Pienaar, Elizabeth; Wiysonge, Charles S.
    Vaccine hesitancy is a phenomenon where individuals delay or refuse to take some or all vaccines. The objective of this study was to conduct a global bibliometric analysis of research productivity and identify country level indicators that could be associated with publications on vaccine hesitancy. We searched PubMed and Web of Science for publications from 1974 to 2019, and selected articles focused on behavioral and social aspects of vaccination. Data on country-level indicators were obtained from the World Bank. We used Spearman’s correlation and zero-inflated negative-binomial regression models to ascertain the association between country level indicators and the number of publications. We identified 4314 articles, with 1099 eligible for inclusion. The United States of America (461 publications, 41.9%), Canada (84 publications, 7.6%) and the United Kingdom (68 publications, 6.2%) had the highest number of publications. Although various country indicators had significant correlations with vaccine hesitancy publications, only gross domestic product (GDP) and gross national income (GNI) per capita were independent positive predictors of the number of publications. When the number of publications were standardized by GDP, the Gambia, Somalia and Malawi ranked highest in decreasing order. The United States, Canada and United Kingdom ranked highest (in that order) when standardized by current health expenditure. Overall, high-income countries were more productive in vaccine hesitancy research than low-and-middle-income countries. There is a need for more investment in research on vaccine hesitancy in low-and-middle-income countries.
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    A systematic review of strategies for reducing missed opportunities for vaccination
    (Elsevier, 2018) Jaca, Anelisa; Mathebula, Lindi; Iweze, Arthur; Pienaar, Elizabeth; Wiysonge, Charles S.
    Background: Missed opportunities for vaccination (MOVs) occur when persons eligible for vaccination visit a health facility and do not get the vaccines they need. We conducted a systematic review to assess effects of interventions for reducing MOVs. Methods: We searched PubMed, Scopus, and the Cochrane Central Register of Controlled Trials in April 2017. Three authors independently screened search outputs, reviewed potentially eligible papers, assessed risk of bias, and extracted data; resolving disagreements by consensus. We expressed study results as risk ratios (RR) with 95% confidence intervals (CI) and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool. Results: Six studies (five trials and one cohort study) met our inclusion criteria, all conducted in the United States of America. All six studies had various limitations and were classified as having a high risk of bias. We found moderate certainty evidence that the following interventions probably improve vaccination coverage: patient education (RR 1.92, 95% CI 1.38–2.68), patient tracking using community health workers (RR 1.18, 95% CI 1.11–1.25), and patient tracking and provider prompts (RR 1.24, 95% CI 1.18–1.31). In addition, we found low certainty evidence that concurrent interventions targeting health-facility (education, prompts, and audit and feedback) and family settings (phone calls) may increase vaccination coverage (RR 1.25, 95% CI 1.08–1.46). Conclusions: The currently available evidence suggests that patient education, patient tracking, outreach sessions, and provider prompts reduce missed opportunities for vaccination and improve vaccination coverage. Rigorous studies are required to confirm these findings and increase the certainty of the current evidence base. WHO is currently coordinating efforts to generate such evidence, especially from low-income and middle-income countries, and it is likely that the data will be available in the next few years.