Injecting a TB vaccine into the blood, not the skin, boosts its effectiveness
The BCG vaccine is notoriously bad at preventing the most common form of tuberculosis
By Tara Haelle
Delivering a high dose of a vaccine against tuberculosis intravenously, instead of under the skin, greatly improves the drug’s ability to protect against the deadly disease, a new study finds.
Changing the typical dose and method of administration of the bacille Calmette-Guérin, or BCG, vaccine prevented TB in 90 percent of rhesus monkeys, researchers report online January 1 in Nature.
Most “astonishing” is that six of the 10 monkeys who received the IV vaccine never even developed an initial infection when exposed to TB, says Joel Ernst, an immunologist who specializes in TB at the University of California, San Francisco. Preventing infection, not just disease — called sterilizing immunity — is extremely rare with any TB vaccine, says Ernst, who was not involved in the study. Thwarting that infection means that no bacteria can reactivate to cause a latent or active TB infection.
The BCG vaccine has been around for nearly a century and is the only currently licensed TB vaccine. More than 150 countries, but not the United States, regularly use BCG to protect infants against some forms of TB. But the vaccine often fails to prevent the most common type of tuberculosis infection, in the lungs, in adolescents or adults.