Vaccines can prevent TB infections in adolescents

Vaccines can prevent TB infections in adolescents

Context:

•   A clinical trial has provided encouraging new evidence that TB vaccines can prevent sustained infections in high-risk adolescents.

Introduction:

• The results will be announced at the 5th Global Forum on TB Vaccines in New Delhi.
• The study was conducted to evaluate the safety and immunogenicity of the vaccine regimens, as well as their ability to prevent initial and sustained TB infections among healthy adolescents in the Western Cape Province of South Africa.

Rationale behind this trial:

• The result from this novel trial design will provide significant scientific benefit to the field in understanding TB infection, and based on this positive signal.

Subunit vaccine

• In the Phase 2 trial conducted in South Africa, revaccination with the Bacille Calmette-Guerin (BCG) vaccine significantly reduced sustained TB infections in adolescents.
• An experimental vaccine candidate, H4:IC31, also reduced sustained infections, although not at statistically significant levels.
• The trend observed for H4:IC31 is the first time a subunit vaccine has shown any indication of ability to protect against TB infection.

World Health Organisation data:

• TB is the world’s leading cause of death from an infectious disease
• According to the World Health Organisation, about one-third of the world’s population has latent TB infection, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.
• People infected with TB bacteria have a lifetime risk of falling ill with TB of 10%.
• People ill with TB can infect 10-15 other people through close contact over the course of a year.
• Without proper treatment, 45% of HIV-negative people with TB on average and nearly all HIV-positive people with TB will die.