New vaccines needed
The BCG vaccine is one of the oldest vaccines, but there are still several crucial unanswered questions about its use.
Previously published studies that examined the protective effect of BCG vaccination only considered low-burden settings and the historical literature before 1950. These studies need updating, but doing so has not been a simple task. To answer their questions, individual-level participant data for a prespecified list of variables, including the characteristics of the exposed participant (contact), the index case, and the environment, were requested from authors of all eligible studies.
Much of the data used in the published research were found through discussions with authors and experts in the field, as well as through data deposited in data storage repositories, conference abstracts, dissertations, and even direct requests to the authors. “The Pan-American Health Organization helped with this data collection and contacting some authors,” said Dr. Croda.
With the new data, the authors confirmed that infant BCG vaccination, although important to young children who are at high risk for tuberculosis, does not prevent adult-type cavitary tuberculosis and is therefore insufficient to impede the tuberculosis epidemic. “Novel vaccines are urgently needed,” they concluded.
“We need to develop novel, more effective vaccines, which, when administered during infancy, would ensure lifelong protection,” Dr. Croda added.
Dr. Croda and Dr. Ballalai reported no relevant financial relationships.
This article was translated from the Medscape Portuguese edition. A version of this article appeared on Medscape.com.