Is early tuberculosis death associated with increased tuberculosis transmission?

Area of Science:

• Infectious Diseases
• Epidemiology
• Public Health

Background:

• Tuberculosis (TB) is uncommon in high-income countries, potentially leading to delayed diagnosis and death.
• The transmission risk associated with early TB-related death remains largely unknown.

Purpose of the Study:

• To determine the transmission risk attributable to early tuberculosis death.
• To compare the transmission potential of TB patients who die early versus those who survive initial treatment.

Main Methods:

• A case-control study was conducted in Alberta, Canada (1996-2012).
• Cases were adults with culture-positive pulmonary TB who died within 60 days of treatment initiation.
• Controls were culture-positive pulmonary TB survivors matched by age, sex, population group, and smear status. Transmission was assessed using molecular and conventional epidemiology.

Main Results:

• Patients who died early from TB were not more likely to transmit the disease than those who survived beyond 60 days of treatment.
• This finding held true regardless of how transmission was measured, including secondary cases and infections in contacts.

Conclusions:

• In low TB incidence and low HIV prevalence settings, pulmonary TB patients dying early and those surviving the initial treatment phase pose an equal transmission risk.
• Early death from TB does not appear to be a significant driver of increased disease transmission in these contexts.