Year: 2015
Type: article
Abstract: We thank S. Hermans et al., for their interest and thoughtful comments regarding our recent publication. They point out that the estimated median duration of time between TB infection and disease is 4–9 months in HIV-uninfected persons and question our assumption that TB may have been acquired by HIV-uninfected patients with TB at the healthcare facilities they reported visiting in the 1 month prior to TB treatment. In clarification, our investigation did not assume that TB was acquired during the 1 month prior to presentation with TB disease. As noted in the methods section, we intentionally limited the period of recall during TB case interviews for both social contacts and geographic sites visited, in an effort to maximise the quality of data collected. As a result, in the analysis, we assume that sites visited by HIV-uninfected patients with TB in the month prior to TB treatment are relatively stable over time and representative. We acknowledge that this assumption may be less likely to extend to healthcare facilities among HIV-uninfected patients with TB, as they presumably visit healthcare facilities less often than HIV-infected persons, prior to developing TB disease. However, suggested in Hermans’ et al. comment is an assumption that HIV-uninfected persons do not seek health care routinely for other reasons prior to TB disease. To the contrary, healthcare utilisation among HIV-uninfected persons in rural Uganda is common, and proximity to a given health centre is a frequently cited factor in choice of health centre 1. This suggests that HIV-uninfected persons make stable choices based on proximity in where they seek health care over time, whether for TB or other types of illnesses. Additionally, we did not attempt to determine the direction of transmission (i.e. who infected whom) in our study population, or whether or not a common, unidentified source patient could have existed between two genotype-clustered cases in our study. For example, two HIV-uninfected persons in our study could have acquired TB from a shared, infectious TB case (not identified by our study) at a specific health facility and then been enrolled in our study 4–9 months later when presenting with TB disease at the same facility. We agree with Hermans et al. that whether or not the health facilities identified were sites of TB acquisition, or locations of onward spread of TB to others, identifying these sites remains important as a starting point to target prevention and screening efforts.
DOI: 10.1111/tmi.12504
Authors: Gabriel Chamie, Edwin D. Charlebois
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4241304246