Occupational Exposure to Tuberculosis among Health Care Workers: Retrospective Cohort Study at Health Facilities in Lusaka,Zambia

Abstract

Tuberculosis (TB) is classified as one of the occupational diseases and Health Care Workers (HCWs) are considered one of the vulnerable groups to acquiring TB due to its mode of transmission. The health facility being a source of infection for the HCWs creates a vicious cycle of TB infection back to the communities. This study aimed to establish the burden of TB among HCWs, assess the working environment of HCWs working from high risk areas as well as understand their perceptions with regards infection prevention and the use of Personal Protective Equipment. A concurrent mixed methods study design was used with the larger part being quantitative. The study combined retrospective cohort and qualitative case study designs. Information on TB cases amongst HCWs at facilities that offer TB services was gathered. A checklist was used to assess environmental working conditions. Interviews with HCWs from high risk areas using a semi-structured questionnaire was used in the qualitative study. The quantitative data collected was analysed using Stata version 12. Descriptive characteristics, univariate and multivariate analysis using logistic regression was done providing crude and adjusted odds ratios. Thematic analysis was used to analyse the qualitative data by establishing themes. Triangulation was done at discussion phase of the study. The prevalence of TB among HCWs was 1801 per 100,000 persons. This is three times higher than that of the general population in Zambia. The TB low risk area accounted for 70% of the TB cases recorded. Majority of cases recorded were female (61.5%). Professionals had the highest recorded cases of 47%. Adjusting for professionals Community volunteers and Support staff had increased odds of 8.6 (AOR 8.2 CI, 1.61-41.6) and 1.11 (AOR 1.4 CI, 0.23-8.52) of acquiring TB respectively. All health facilities largely depended on natural ventilation although mechanical ventilation was applied where natural ventilation was insufficient. Interviews revealed that all HCWs were aware of TB, its modes of transmission and that they were at risk. The respondents felt that they were better placed as they were more likely to exercise caution compared to HCWs from low risk areas. This is largely due to the fact that they handled confirmed cases of TB. Similar studies should be done for HCWs from TB low risk areas. Periodic screening for TB among HCWs should be encouraged to provide better monitoring and evaluation of surveillance data and infection prevention measures.