Table of contents:
Tuberculosis vaccination linked to reduced risk of lung cancer
Vaccination against tuberculosis during childhood is associated with a reduced risk of lung cancer. Scientists associate additional effects of the BCG vaccine with its effect on immunity.
Photo: CC0 /
Vaccination against tuberculosis in childhood is associated with a reduced risk of lung cancer, according to American scientists in an article published in the JAMA Network Open.
The study by Nicholas T. Usher and colleagues at the University of Military Medicine in Maryland spanned 60 years. Scientists analyzed the medical data of 2,963 people - Native Americans and Alaska Natives. The authors conducted a secondary analysis of data from the BCG vaccine study conducted in five US states from 1936 to 1998.
Participants at school age received the BCG vaccine against tuberculosis or a placebo (saline) injection. Scientists set out to find out if vaccination had any connection with lung cancer in later life.
In their initial analysis of the data, the researchers found that there was no significant difference in the prevalence of various cancers in both groups. But then the authors took into account the impact of other possible factors that can cause cancer: gender, smoking, alcohol consumption, tuberculosis disease. After such an amendment, it turned out that people vaccinated with the BCG vaccine had less lung cancer: 18.2 versus 45.4 cases per 100,000 people.
“The mechanism of the observed protective action is unknown, but the link was strong and scientifically plausible; we assume that immunity may have played a role,”the scientists write.
Tuberculosis in the study was not associated with lung cancer. The scientists write that this "is consistent with existing evidence that BCG vaccine exposure is associated with different immunological mechanisms independent [of tuberculosis]." The authors also noted that their results do not confirm the data of some scientists, who reported an increased risk of lymphomas and leukemias in people vaccinated against tuberculosis.