Earlier this month, results from a two-year clinical trial showed that a new vaccine for tuberculosis is not as effective as researchers had hoped. Previous clinical trials proved the vaccine to be fairly effective in adults, but the most recent trial showed that it does not provide significant protection for infants.

The news was a major blow to modern medicine, which has been seeking a more effective TB vaccine for decades.  The latest trial involved the first new vaccine to reach the human-trial stage since 1921.

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