Related Experiment Video
Updated: Jul 9, 2026

Protective Efficacy and Pulmonary Immune Response Following Subcutaneous and Intranasal BCG Administration in Mice
Published on: September 19, 2016
[BCG vaccine against tuberculosis: its protective effect and vaccination policies]
Susan M Pereira1, Odimariles Maria Souza Dantas, Ricardo Ximenes
1Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, BA, Brazil. susanmp@ufba.br
Objective:
The BCG vaccine has been in use since 1921, but still arouses controversy and uncertainties. The objective was to analyze the protective effect of the BCG vaccine in its first and second doses and the accompanying vaccination policies.
Methods:
A systematic review of the literature in both English and Spanish was carried out, covering the period 1948 to 2006, using the PubMed database. The main search terms used included BCG vaccine, BCG efficacy, BCG and tuberculosis. The studies were grouped by design, with the main results from the clinic tests, case-control studies and meta-analyses presented separately.
Results:
The protective effect of the first dose of the BCG vaccine against tuberculosis in its miliary and meningeal forms is high. However, the results vary in relation to the pulmonary form of the disease, with some indicating zero effect and others levels of nearly 80%. Research is being carried out to develop new vaccines that could substitute the BCG or be used as a booster.
Conclusions:
There are evidences that the protective effect of the BCG vaccine does not increase with a second dose. In spite of its limitations and the expectation that a new tuberculosis vaccine will be developed in the future, the BCG vaccine remains an important tool in controlling the harmful effects of tuberculosis, particularly in countries with medium or high incidence levels of the disease.
Related Concept Videos
Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the progression...
Smallpox
Pulmonary Tuberculosis I
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...
Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
Tuberculosis
Cancer Vaccines
Cancer vaccines come in two categories: preventive (prophylactic) and treatment (active). Preventive vaccines, such as the Human Papillomavirus (HPV) vaccine, protect against viruses that cause certain...

