Dataset Information

Prevalence and risk factors for latent tuberculosis infection among household contacts of index cases in two South African provinces: Analysis of baseline data from a cluster-randomised trial.

ABSTRACT: INTRODUCTION:Household contacts of patients with active pulmonary tuberculosis (TB) often have latent TB infection, and are at risk of progression to disease. We set out to investigate whether index TB case HIV status was linked to a higher probability of latent TB infection among household contacts. MATERIALS AND METHODS:Data were collected prospectively from participants in the intervention arm of a household cluster-randomised trial in two South Africa provinces (Mangaung, Free State, and Capricorn, Limpopo). In intervention group households, TB contacts underwent HIV testing and tuberculin skin testing (TST). TST induration was estimated at two cut-offs (?5mm, ?10mm). Multilevel Bayesian regression models estimated posterior distributions of the percentage of household contacts with TST induration ?5mm and ?10mm by age group, and compared the odds of latent TB infection by key risk factors including HIV status index case age and study province. RESULTS:A total of 2,985 household contacts of 924 index cases were assessed, with most 2,725 (91.3%) undergoing TST. HIV prevalence in household contacts was 14% and 10% in Mangaung and Capricorn respectively. Overall, 16.8% (458/2,725) had TST induration of ?5mm and 13.1% (359/2,725) ?10mm. In Mangaung, children aged 0-4 years had a high TST positivity prevalence compared to their peers in Capricorn (22.0% vs. 7.6%, and 20.5% vs. 2.3%, using TST thresholds of ?5mm and ?10mm respectively). Compared to contacts from Capricorn, household contacts living in Mangaung were more likely to have TST induration ?5mm (odds ratio [OR]: 3.08, 95% credibility interval [CI]: 2.13-4.58) and ?10mm (OR: 4.52, 95% CI: 3.03-6.97). There was a 90% and 92% posterior probability that the odds of TST induration ?5mm (OR: 0.79, 95% CI: 0.56-1.14) and ?10mm (OR: 0.77, 95% CI: 0.53-1.10) respectively were lower in household contacts of HIV-positive compared to HIV-negative index cases. CONCLUSIONS:High TST induration positivity, especially among young children and people living in Mangaung indicates considerable TB transmission despite high antiretroviral therapy coverage. Household contact of HIV-positive index TB cases were less likely to have evidence of latent TB infection than contacts of HIV-negative index cases.

SUBMITTER: MacPherson P

PROVIDER: S-EPMC7077873 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Prevalence and risk factors for latent tuberculosis infection among household contacts of index cases in two South African provinces: Analysis of baseline data from a cluster-randomised trial.

MacPherson Peter P Lebina Limakatso L Motsomi Kegaugetswe K Bosch Zama Z Milovanovic Minja M Ratsela Andrew A Lala Sanjay S Variava Ebrahim E Golub Jonathan E JE Webb Emily L EL Martinson Neil A NA

PloS one 20200317 3

<h4>Introduction</h4>Household contacts of patients with active pulmonary tuberculosis (TB) often have latent TB infection, and are at risk of progression to disease. We set out to investigate whether index TB case HIV status was linked to a higher probability of latent TB infection among household contacts.<h4>Materials and methods</h4>Data were collected prospectively from participants in the intervention arm of a household cluster-randomised trial in two South Africa provinces (Mangaung, Free ...[more]

PMID: 32182274

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Project description:At-home rapid COVID-19 tests in the U.S. utilize nasal-swab specimens and require high viral loads to reliably give positive results. Longitudinal studies from the onset of infection have found infectious virus can present in oral specimens days before nasal. Detection and initiation of infection-control practices may therefore be delayed when nasal-swab rapid tests are used, resulting in greater transmission to contacts. We assessed whether index cases first identified by rapid nasal-swab COVID-19 tests had more transmission to household contacts than index cases who used other test types (tests with higher analytical sensitivity and/or non-nasal specimen types). In this observational cohort study, 370 individuals from 85 households with a recent COVID-19 case were screened at least daily by RT-qPCR on one or more self-collected upper-respiratory specimen types. A two-level random intercept model was used to assess the association between the infection outcome of household contacts and each covariable (household size, race/ethnicity, age, vaccination status, viral variant, infection-control practices, and whether a rapid nasal-swab test was used to initially identify the household index case). Transmission was quantified by adjusted secondary attack rates (aSAR) and adjusted odds ratios (aOR). An aSAR of 53.6% (95% CI 38.8-68.3%) was observed among households where the index case first tested positive by a rapid nasal-swab COVID-19 test, which was significantly higher than the aSAR for households where the index case utilized another test type (27.2% 95% CI 19.5-35.0%, P = 0.003 pairwise comparisons of predictive margins). We observed an aOR of 4.90 (95% CI 1.65-14.56) for transmission to household contacts when a nasal-swab rapid test was used to identify the index case, compared to other test types. Use of nasal-swab rapid COVID-19 tests for initial detection of infection and initiation of infection control may be less effective at limiting transmission to household contacts than other test types.

Project description:Background: Andes orthohantavirus (ANDV) is the sole etiologic agent of Hantavirus Cardiopulmonary Syndrome in Chile and, until now, the only Hantavirus known to be transmitted by person-to-person route. The main risk of person-to-person transmission is to be a sexual partner of an index case, and deep kissing the main mechanism of infection. Experimental reports suggest that ANDV infection can be inhibited by some saliva components. Therefore, some host factors like saliva quality, could help to explain why some individuals do not become infected even though their exposure to the virus is high. Aim: To compare some saliva components, such cytokines and mucins, between ANDV-infected cases (exposed-sick), their close household contacts (exposed-not sick) and healthy control not exposed. Methods: Sixty-nine confirmed ANDV-infected cases, 76 close household contacts exposed to ANDV but not infected (CHC) and 39 healthy control not exposed (HCNE). The following components were measured in saliva: secretory immunoglobulin A (sIgA) by ELISA; cytokines (IL1β, IL12p70, TNFα, INFy, IL10, IL6, VEGF, IP10, and IL8) by Multiplex Assay and mucins MUC7 and MUC5B by Western Blotting. Results: Among infected cases, CHC and HCNE analyzed 74, 45, and 33% were men, respectively (p ≤ 0.05). The average age for cases, CHC and HCNE was 37.7, 28.7, and 32 years, respectively (p ≤ 0.05). The average concentration of sIgA in infected cases was 4.846 mg/mL, higher than for CHC group, 0.333 mg/mL (p ≤ 0.05). For cytokines, significant differences were found comparing all groups for IFNy, IL12p70, and IL8. Among CHC group, there was a higher frequency of detection of MUC7 isoform (62.6%; 31/49) compared to ANDV-infected cases (40.5%; 17/42) (p < 0.05). Similarly, presence of MUC5B was higher among CHC groups (62.16%; 46/74) than in ANDV-infected cases (44.4%; 28/63) (p < 0.05). Conclusions: Three salivary components showed differences between infected cases and close household contacts (sIgA, cytokines, and mucins). These differences can be explained by the acute state of the disease in the ANDV-infected cases group. However, the differences in MUC5B and isoforms of MUC7 are not entirely explainable by the infection itself. This work represents a novel description of salivary components in the context of ANDV infection.

Dataset Information

Prevalence and risk factors for latent tuberculosis infection among household contacts of index cases in two South African provinces: Analysis of baseline data from a cluster-randomised trial.

Publications

Prevalence and risk factors for latent tuberculosis infection among household contacts of index cases in two South African provinces: Analysis of baseline data from a cluster-randomised trial.

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