Vaccine-preventable diseases other than tuberculosis, and homelessness: A systematic review of the published literature, 1980 to 2020

Abstract

AbstractBackgroundHomelessness may result in the breakdown of regular health services, including routine vaccination programmes. A literature review was conducted to describe vaccine-preventable diseases (VPD) other than tuberculosis in homeless populations and to summarize vaccination recommendations in homeless people.MethodsWe followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We searched peer-reviewed literature published in English, French or Spanish reporting the outbreak of VPD or VPD prevalence in both infant and adult homeless populations published between 1980 and 2020, using PubMed/Medline, SciELO, Google Scholar, and Web of Science databases. Relevant information from the studies was charted in Microsoft Excel and results were summarised using a descriptive analytical method.ResultsSeventy-five articles were included. A high prevalence of past HBV and HAV infections were observed through serosurveys, mostly in high income countries or high-middle income countries (USA, Canada, France, Iran or Brazil). Nine outbreaks of HAV infection were also reported, with lethality rates ranging from 0-4.8%. The studies discussed numerous risk factors positively associated with HBV infection, including older age, homosexual or bisexual practice, injected drug use (IDU), and, with HAV infection including IDU, having sexual partner(s) with a history of unspecified hepatitis, insertive anal penetration, or originating from a country with a high prevalence of anti-HAV antibody. Eleven outbreaks of pneumococcal infection affecting homeless persons were reported in Canada and USA, with lethality rates from 0-15.6%. Five diphtheria outbreaks were reported. Vaccination status was rarely documented in these studies.ConclusionsThe literature suggests that homeless populations generally experience a higher VPD burden and lower immunisation rates. The findings suggest the need for a national vaccination programme and planning for delivering vaccines in this population.