Systematic Review of the Time Interval of Infectivity After Treatment Starts in Patients With Pulmonary Tuberculosis

Name: ILAMAN ARMAND XAVIER

Publication date: 03/04/2017
Advisor:

Namesort descending Role
MOISES PALACI Advisor *

Examining board:

Namesort descending Role
CRISPIM CERUTTI JUNIOR Internal Examiner *
ETHEL LEONOR NOIA MACIEL External Examiner *
MOISES PALACI Advisor *

Summary: The success of tuberculosis (TB) control depends on early and effective prevention of transmission of Mycobacterium tuberculosis (MTB) from infectious patients. The lack of clarity as to the time of sputum conversion and the expulsion of viable MTB after initiation of treatment under programmed conditions compromises the necessary control of the disease. This study aimed to determine the limiting period of infectivity of pulmonary tuberculosis after starting treatment through a systematic review from January 1970 to January 2017. Our data sources were MEDLINE, LILACS, EMBASE and the question formulation was synthesized by the acronym P.I.C.O. The searches yielded 11,920 records. After analyzing the titles, abstracts and removal of duplicates, 60 articles were included. The first group summarizes the studies in which the time interval of tuberculosis infectivity does not exceed 14 days after the beginning of treatment. The second group represents 6 studies that reveal evidence of viable bacilli transmission after more than 14 days after initiation of treatment. And the third group that brings together 16 studies in which the infectivity of tuberculosis has been proven beyond 3 weeks from the beginning of the treatment. 21 and 59 days were considered as the minimum and maximum release periods for viable bacilli, respectively. The mean and median values are estimated at 37.12 and 36.5 days. Factors such as high initial bacillary load, bilateral pulmonary involvement, and presence of cavity are the most indexed and represent a greater impact. Smoking, advanced age, diabetes mellitus, alcoholism, HIV, male sex and malnutrition are important factors, as they also play a crucial role in the persistence of infectivity after the initiation of anti-TB therapy. This study demonstrated that patients with pulmonary TB who initiate multidrug therapy remain highly infectious for much longer than is conventionally believed. It would be dogmatic to define a fixed time as the limit of non-infectivity, given the fact that there are specific situations that affect the dynamic of the bacilli after the start of treatment. It is of great importance to reconsider patient isolation protocols, to take into account the influencing factors and to consider each patient case by case.

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