Archive for November 14, 2018

The calendar of epidemics: Seasonal cycles of infectious diseases

Plos Pathogens November 8, 2018

Micaela Elvira Martinez

Seasonal cyclicity is a ubiquitous feature of acute infectious diseases [1] and may be a ubiquitous feature of human infectious diseases in general, as illustrated in Tables 1–4.

Each acute infectious disease has its own seasonal window of occurrence, which, importantly, may vary among geographic locations and differ from other diseases within the same location.

Here we explore the concept of an epidemic calendar, which is the idea that seasonality is a unifying feature of epidemic-prone diseases and, in the absence of control measures, the local calendar can be marked by epidemics (Fig 1).

A well-known example of a calendar marked by epidemics is that of the Northern Hemisphere, where influenza outbreaks occur each winter [2, 3] (hence the colloquial reference to winter as “the flu season”).

In contrast, chickenpox outbreaks peak each spring [4, 5], and polio transmission historically occurred each summer [6].



November 14, 2018 at 8:32 am

A patient-level pooled analysis of treatment-shortening regimens for drug-susceptible pulmonary tuberculosis

Nature Medicine November 5, 2018

Marjorie Z. Imperial, Payam Nahid, Patrick P. J. Phillips, Geraint R. Davies, Katherine Fielding, Debra Hanna, David Hermann, Robert S. Wallis, John L. Johnson, Christian Lienhardt & Rada M. Savic

Tuberculosis kills more people than any other infectious disease. Three pivotal trials testing 4-month regimens failed to meet non-inferiority margins; however, approximately four-fifths of participants were cured.

Through a pooled analysis of patient-level data with external validation, we identify populations eligible for 4-month treatment, define phenotypes that are hard to treat and evaluate the impact of adherence and dosing strategy on outcomes.

In 3,405 participants included in analyses, baseline smear grade of 3+ relative to <2+, HIV seropositivity and adherence of ≤90% were significant risk factors for unfavorable outcome.

Four-month regimens were non-inferior in participants with minimal disease defined by <2+ sputum smear grade or non-cavitary disease. A hard-to-treat phenotype, defined by high smear grades and cavitation, may require durations >6 months to cure all.

Regimen duration can be selected in order to improve outcomes, providing a stratified medicine approach as an alternative to the ‘one-size-fits-all’ treatment currently used worldwide…



November 14, 2018 at 8:31 am


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