Background We aim to determine the vaccination coverage of social and healthcare workers in International sites of Samusocial, providing emergency care to homeless people, and to assess factors associated with having received necessary doses at adulthood. Methods Data on immunization coverage of social and healthcare workers were provided by a cross-sectional survey, conducted from February to April 2015 among 252 Samusocial workers in 10 countries. Vaccination status and characteristics of participants were collected through a self-administered questionnaire. Prevalence rate ratio (PRR) of vaccination status was calculated using Poisson regression models. Results Among 252 Samusocial social and health workers who felt a questionnaire, median age was 39 years, 42.1% were female, 88.9% were in contact with homeless beneficiaries (19.1% health workers). Overall, 90.1% of Samusocial staff felt adult vaccinations was useful and 70.2% wished to receive booster doses in future. Vaccination coverage at adulthood was satisfactory for diphtheria and poliomyelitis (96%), but low for influenza (20.8%), meningococcus (50.5%), hepatitis B (56.3%), yellow fever (58.1%), measles (81.3%) and pertussis (90.7%). The main reasons for not having received vaccination booster doses were forgetting the dates of booster doses (38.4%) and not having received the information (13.5%). In adjusted analysis, prevalence of up-to-date for vaccination schedule was 35% higher among health workers than among social workers (aPRR = 1.35, 95%CI: 1.01–1.82, P = 0.05) and was 56% higher among workers who had a documentary evidence of vaccination than in those who did not (aPRR = 1.56, 95%CI: 1.19–2.02, P = 0.001). Conclusions The Samusocial International workers vaccine coverage at adulthood was insufficient and disparate by region. It is necessary to strengthen the outreach of this staff and increase immunization policy for hepatitis B, diphtheria, tetanus, and measles, as well as for yellow fever, rabies and meningococcal ACYW135 vaccines in at risk regions.
