Authors: Mrs Kalo Musukuma-Chifulo. Tracy N. Phiri1, Michelo Simuyandi1, Mutinta Muchimba1 Chikumbutso Chipeta1, Kawana Wamundila2, Obvious N. Chibanyama1, Caroline C. Chisenga1, Paul Somwe1, Cheryl Rudd1, Melissa C. Kapulu3,4, Michael Vinikoor5, Samuel Bosomprah1,6, and Roma Chilengi11 Centre for Infectious Disease Research in Zambia (CIDRZ) 2 The University of Zambia (UNZA) 3 KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya 4 Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK 5 the University of Alabama at Birmingham (UAB) 6 Department of Biostatistics, School of Public health, University of Ghana.
Citation Style For This Article: Musukuma-Chifulo K. Phiri TN, Simuyandi M, et al. Hepatitis B virus among health care workers: exposure, prevalence, and predictors of a lifetime and current infection in a cohort from Kalulushi District, Zambia. Health Press Zambia Bull. 2020; 4(4); pp 21
Background
Infection with the Hepatitis B virus (HBV) among health care workers (HCWs) is an occupational hazard that can be mitigated by HBV vaccination which offers ~90-95% protective efficacy when combined with other preventive measures. Exposure to the virus elicits an antibody response which when sufficient can prevent infection from establishing. On the other hand, antibodies to the core antigen serve as a marker of lifetime infection (i.e., if ever exposed), while an acute or chronic infection is marked by the detection and presence of the surface antigen. However, the level of exposure and risk factors are currently not understood in our setting that would allow for vaccine introduction in HCWs. We thus set out to evaluate the exposure, prevalence, and describe the predictors of a lifetime and current infection of HBV amongst HCWs.
Methods
We recruited a cohort of consenting HCWs across 23 health facilities and two nursing schools from Kalulushi District, Copperbelt Province, Zambia. Current or previous infection with HBV was determined by the detection of surface antigen (HBsAg), core antibody (anti-Hbc), and surface antibody (anti-HBs) using established enzyme-linked immunosorbent assay (ELISA) methods. All HBsAg positive volunteers were referred for clinical care. Social demographic characteristics [age, sex, institution type, and category of staff] were collected for each participating HCW. All categorical variables were summarized using proportions. Chi-square or fisher’s exact test was used to test for association between the volunteer’s social demographic characteristics, and HBsAg, and anti-HBc status. In addition, univariate and multivariate logistic regression was used to determine risk factors of HBsAg and anti-HBc status. All statistical analysis was done using STATA version 16.0 and statistical significance was set at p< 0.05.
Results
A total of 673 HCWs were recruited to participate in the study. The median age was 28 (IQR: 24-36) with the majority being female (72.4%, 487/673). Out of these, 15.5% (104/673) were not included in the analysis due to missing demographic or volunteer characteristic data. The majority of the volunteers were from the general hospital (34.1%, 194/569) whilst 29.7% (169/569) were from the nursing school; 13.7% (78/569) from health posts, and 22.5% (128 /569) from health centers with the majority of these being students (24.1%, 137/569); 47.5% (270/569) medical staff; and 28.5% (162/569) support staff. For Hepatitis B exposure, 66.8% (380/569) were anti-HBc positive while 4.6% (26/567) were HBsAg positive. Using the cut-off of 10 IU/ml, 79.8% (454/569) were eligible for vaccination. A health care worker was more likely to have higher exposure to Hepatitis B as determined by anti-HBc, if they were a student [OR 1.8(95%CI 1.1-2.9) p =0.012] in the univariate analysis, however, this was not significant in the adjusted model.
Conclusion/Recommendations
Lifetime HBV infection is high among HCWs, similar to previous reports in the region; however, only a minority of individuals, regardless of prior HBV infection, have immunity based on antibody concentration. Following this, the program will provide vaccination and describe the profile of antibody responses post-vaccination, and implementation outcomes to inform a national scale-up of HBV testing, treatment, and prevention for Zambian HCWs.