BCG World Atlas Published to Aid Fight Against Tuberculosis

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Tuberculosis (TB) continues to be a major global health threat. Every second, someone in the world is newly infected with TB bacteria. Every year, more than 9 million people develop active TB. Every year, TB claims about 2 million lives.

A team of researchers from McGill University and the Research Institute of the McGill University Health Centre (RI MUHC) is using the approaching World TB Day 2011 (Thursday March 24) to officially launch the BCG World Atlas.

The BCG World Atlas is a first-of-its-kind, easy-to-use, searchable website that provides free detailed information on current and past TB vaccination policies and practices for more than 180 countries.

"The Atlas is designed to be a useful resource for clinicians, policymakers and researchers alike," said co-author Dr. Madhukar Pai, who is an assistant professor at McGill's Dept. of Epidemiology, Biostatistics & Occupational Health and a researcher in the Respiratory Epidemiology and Clinical Research Unit at the Montreal Chest Institute and the RI MUHC. "It has important implications on diagnosing and treating TB and on the research that's being done on developing a new TB vaccine."

Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs. But, TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal. TB disease was once the leading cause of death in the United States.

Symptoms of tuberculosis include feelings of sickness or weakness, weight loss, fever, and night sweats. When the disease is in the lungs, the symptoms may also include coughing, chest pain, and the coughing up of blood.

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The Bacille Calmette-Guérin (BCG) vaccine was introduced in 1921 and continues to be the only vaccine used to prevent TB. Despite nearly a century of use, the vaccine remains controversial, with known variations in efficacy, strains, policies and practices across the world.

It is important for clinicians to be aware of the various BCG policies in different parts of the world, as well as changes to those policies over time, especially when dealing with foreign-born adults who were vaccinated as children and who are unlikely to have retained their childhood vaccination records. The BCG World Atlas can help with this.

The Atlas project began in 2007 with the compilation of detailed information on past and present BCG vaccination policies on as many countries as possible. The data were assembled through respondent-completed questionnaires, published papers, reports, government policy documents and data available from the World Health Organization Vaccine Preventable Diseases Monitoring System. The beta version of the site went live in 2008 and over the past year more than 6,000 visits have been recorded with a steady increase in traffic over time. The Atlas is constantly being updated and its authors welcome input from countries that are currently not covered.

Ms. Alice Zwerling, BCG Atlas project leader and PhD candidate in epidemiology at McGill, explained that BCG vaccination can cause false positives in the skin test that's routinely used to screen for latent TB. "As a clinician, if you're trying to interpret the skin test in a foreign-born person, you're going to want to know when the BCG vaccination was given back home and how many times it has been given. The Atlas provides this information and can help doctors decide on when to use the newly available blood tests for TB that are not affected by BCG vaccination," she added.

You can listen to Dr. Pai explain the atlas in this youtube video.

Sources
McGill University Press Release

The BCG World Atlas: A Database of Global BCG Vaccination Policies and Practices; Zwerling A, Behr MA, Verma A, Brewer TF, Menzies D, Pai M; PLos Medicine, March 2011

BCG World Atlas

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