Prevalence and risk factors for latent tuberculosis infection among primary health care workers in Brazil

Thiago Nascimento do Prado, Lee W. Riley, Mauro Sanchez, Geisa Fregona, Renata Lyrio Peres Nóbrega, Lia Gonçalves Possuelo, Eliana Zandonade, Rodrigo Leite Locatelli, Fernanda Mattos de Souza, Jayant V. Rajan, Ethel Leonor Noia Maciel

Health care workers (HCW) are at increased risk of latent tuberculosis infection (LTBI) from occupational exposure to Mycobacterium tuberculosis. The objective was to determine the prevalence of and risk factors for LTBI among primary HCW in five Brazilian cities. We conducted a cross-sectional study, from 2011 to 2013, among primary HCW, using a structured questionnaire and an evaluated for LTBI using the Quantiferon-TB Gold in-tube test. The magnitude of the associations was assessed using hierarchical logistic regression models. Among 708 HCW, the LTBI prevalence was 27% (n = 196; 95%CI: 24%-31%). We found that the following factors were positively associated with LTBI in primary HCW: age > 50 years (OR = 2.94; 95%CI: 1.44-5.99), absence of a BCG scar (OR = 2.10; 95%CI: 1.28-3.43), self-reported ex-smoker status (OR = 1.80; 95%CI: 1.04-3.11), being a nurse (OR = 2.97; 95%CI: 1.13-7.83), being a nurse technician (OR = 3.10; 95%CI: 1.26-7.60), being a community health agent (OR = 2.60; 95%CI: 1.06-6.40), and irregular use of N95 masks (OR = 2.51; 95%CI: 1.11-5.98). In contrast, HCWs who do not work in health care facilities with a TB control program were less likely to have LTBI (OR = 0.66; 95%CI: 0.45-0.97). This study demonstrated a substantial occupational risk of LTBI among primary HCW in Brazil. The Brazilian TB control program, as well as local programs, need to target these high-risk HCW with education, as well as with better personal protective equipment to prevent acquisition of new TB infection.