A systematic review of adult tetanus-diphtheria-acellular (Tdap) coverage among healthcare workers

During the last decades pertussis incidence raised globally. Several vaccination strategies targeting adults to reduce pertussis among young infants have been proposed, including vaccination of healthcare workers (HCWs). The aim of this study was to analyse, by performing a systematic review of literature, published papers that evaluated Tdap coverage among HCWs, variables associated with vaccine uptake and efforts implemented to raise vaccination rates. We searched the MedLine, Embase, SCOPUS, LILACS, Web of Science and Cochrane for full-text studies that evaluated Tdap coverage in HCW. Two independent reviewers screened the articles and extracted the data. Twenty-eight studies published from 2009 to 2018 were reviewed. Most studies were conducted in the USA. Initial Tdap coverage varied from 6.1% to 63.9%. USA and France are the only two countries with studies evaluating Tdap coverage within HCWs using national data. In the USA, Tdap coverage in HCWs raised from 6.1% to 45.1% from 2007 to 2015. In the analysis of French national data, a Tdap coverage of 63.9% was observed. Five studies used interventions to raise Tdap coverage in HCWs. Two intervention studies implemented mandatory vaccination and three used educational strategies. All of them achieved coverages over 86%. Only eleven studies analysed the association of Tdap vaccination with variables of interest. Previous immunization with other vaccines recommended for HCWs (like influenza, hepatitis B and MMR) was positively associated with Tdap uptake in four studies. In conclusion, overall Tdap coverage among HCWs is low, but seems to increase over the years after the vaccine introduction and with implementation of interventions to increase coverage.