Impact of Latent Tuberculosis on Severity and Outcomes in Admitted COVID-19 Patients

Abstract

BackgroundThere is limited data on coronavirus disease 2019 (COVID-19) and latent tuberculosis infection (LTBI). MethodologyWe analyzed data of admitted COVID-19 patients evaluated for LTBI to examine the impact of LTBI on severity, laboratory parameters, and COVID-19 outcome. Prospectively collected data were analyzed for 60 patients who were administered the Mantoux tuberculosis skin test (TST) using five tuberculin units of purified protein derivative. All patients were administered TST irrespective of Bacille Calmette-Guérin (BCG) vaccination status. Comorbidities, clinical features, radiologic involvement, laboratory parameters, and clinical course were analyzed concerning LTBI. ResultsThe mean age was 45.9 (±15.2) years, and 35 (58.3%) patients had non-severe disease. The vast majority (n = 56/60; 93.3%) had been vaccinated with single-dose BCG in infancy or early childhood, as per national immunization guidelines. LTBI was diagnosed in 15 (25%) patients. LTBI prevalence was lower in severe (n = 1/25; 4%) than non-severe (n = 14/35; 40%) COVID-19 (p = 0.01) patients. LTBI patients had lower percentage neutrophil count, higher lymphocyte percentage, higher monocyte count, lower neutrophillymphocyte (NL) ratio, lower alanine aminotransferase, lower C-reactive protein, and lesser radiologic involvement compared to those without LTBI (p < 0.05). Similarly, among the mild COVID-19 subgroup, those with LTBI had higher lymphocyte and monocyte counts and lesser radiologic involvement than those without LTBI (p < 0.05). ConclusionsLTBI patients appear to have milder disease, higher lymphocyte and monocyte count, higher NL ratio, and lesser radiographic involvement. This observation needs to be studied in larger studies using interferon release assays.

Unique Reciprocal Association Seen Between Latent Tuberculosis Infection and Diabetes Is Due to Immunoendocrine Modulation (DM-LTB-1)

“…However, the contribution of such a non-specific immune response, elicited by LTBI, in the setting of diabetes, is not fully understood. It is important to note that the immune status during active TB and LTB are quite different: while active TB is associated with a strong inflammatory reaction, LTB is associated with immunomodulation (Madan et al, 2021 ). Recently, in a small study carried out in India, LTBI was shown to confer significant protection against the severe form of the covid-19 disease (Madan et al, 2021 ).…”

“…It is important to note that the immune status during active TB and LTB are quite different: while active TB is associated with a strong inflammatory reaction, LTB is associated with immunomodulation (Madan et al, 2021 ). Recently, in a small study carried out in India, LTBI was shown to confer significant protection against the severe form of the covid-19 disease (Madan et al, 2021 ). Similarly, the metabolic status of diabetes and pre-diabetes are quite different: while frank diabetes is associated with insulin resistance and deficiency, pre-diabetes is associated with insulin resistance and hyperinsulinemia.…”

Tuberculosis endemicity and BCG vaccination: Protection against COVID-19

“…There have been multiple attempts at assessing the role of latent TB and BCG in prevention from COVID-19 [11,12]. However, our analysis provides up to date data on the same, especially since the pandemic has probably crossed its peak in most countries and is likely to represent the true picture around the globe till we get controlled prospective studies on BCG.…”

Immune responses in COVID-19 and tuberculosis coinfection: A scoping review

“…Initially, we reviewed 2103 studies by title and abstract, of which 22 were chosen for full-text review, the reasons for exclusion are found in Supplementary Material 3. Finally, we included four cross-sectional studies in the present review (13)(14)(15)(16). The selection process is summarized in Figure 2.…”

“…The number of participants ranged from 60 to 133 with a total of 372 to predominantly male, and the mean ages ranged from 43 to 68 years, these characteristics are found in Table 1. Two studies evaluated patients with LTBI (13,14), one patient with aTB (15) and other patients with LTBI and aTB (16). One study evaluated asymptomatic COVID-19 patients (13), and the other three evaluated mild to severe symptomatic patients (14)(15)(16).…”