Tumor necrosis factor (TNF) plays an important role in containing mycobacterial infections. With the rapidly increasing role of TNF inhibitors in dermatology, tuberculosis (TB) is becoming an important and worrisome concern to dermatologists. This paper aims to provide a comprehensive review on the incidence of TB in patients treated with anti-TNF, the variety of TB screening methods, and management of these cases. Various national recommendations have been highlighted. The monoclonal antibodies, infliximab and adalimumab, appear to be more associated with the risk of TB reactivation than the soluble receptor etanercept. Tuberculosis associated with TNF inhibitors, in contrast to classical TB, is more likely to be disseminated, atypical, extra pulmonary, and life threatening. Vigilance for typical and atypical presentations of active TB is mandatory until the end of therapy. Although tuberculin standard test (TST) has been the gold standard for screening of latent TB infection (LTBI) for close to a century, it has several inadequacies and may be unreliable in patients with widespread psoriasis. Interferon gamma release assays (IGRAs) with better diagnostic specificity and sensitivity are a promising adjunct to diagnose LTBI at present. Although appropriate screening and treatment of LTBI will lower the risk of reactivation to a great extent, no chemoprophylactic regimen is fully protective.

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This study assesses the durability of severe acute respiratory coronavirus-2 (SARS-CoV-2) anti-nucleocapsid (anti-N) immunoglobulin G (IgG) after infection, and examines its association with established risk factors among South African healthcare workers (HCWs). Blood samples were obtained from 390 HCWs with diagnosis of coronavirus disease 2019 (COVID-19) for assay of the SARS-CoV-2 anti-N IgG at two time points (Phase 1 & 2) between November 2020 and February 2021. Out of 390 HCWs with COVID-19 diagnosis, 267 (68.5%) had detectable SARS-CoV-2 anti-N IgG antibodies at the end of phase I. These antibodies persisted for 4-5 and 6-7 months in 76.4% and 16.1%, respectively. In the multivariate logistic regression model analysis, black participants were more likely to sustain SARS-CoV-2 anti-N IgG for 4-5 months. However, participants who were HIV positive were less likely to sustain SARS-CoV-2 anti-N IgG antibodies for 4-5 months. In addition, individuals who were <45 years of age were more likely to sustain SARS-CoV-2 anti-N IgG for 6-7 months. Of the 202 HCWs selected for phase 2, 116 participants (57.4%) had persistent SARS-CoV-2 anti-N IgG for an extended mean period of 223 days (7.5 months). Findings support the longevity of vaccine responses against SARS CoV-2 in black Africans.

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