Tuberculosis vaccine improves resistance to malaria

26 February 2019

The BCG tuberculosis vaccine also strengthens the immune system against malaria. This is what researchers at Radboud university medical center discovered. Their results were published in Nature Communications.

Publication: link. 

The group led by Mihai Netea, theme Infectious diseases and global health, previously demonstrated that a BCG vaccination, the vaccine against tuberculosis, can 'train' the cells of the congenital immune system to act against other pathogenic microorganisms. For example, early vaccination with the BCG vaccine reduces child mortality, mainly by reducing serious infections. BCG was discovered as early as the 1920s and is one of the most widely used vaccines worldwide. In the Netherlands, the vaccine is not included in the national vaccination program.

"There were indications that BCG could also protect against malaria, but this had not yet been demonstrated in humans," says Robert Sauerwein, theme Infectious diseases and global health. "Because we have more than ten years of experience in the controlled contamination of healthy volunteers with malaria, this seemed a unique opportunity to test the effect of the BCG vaccine on the development of malaria infection." In a controlled study, ten volunteers received the BCG vaccine, and ten volunteers were not vaccinated; five weeks later, they were all stung by malaria mosquitoes.

BCG vaccine also influences the resistance to malaria

The volunteers were closely monitored after exposure to infected mosquitoes and treated immediately if any malaria parasites were found in the blood. "All volunteers developed malaria, but we saw that the immune system was activated more quickly in half of the BCG vaccinated volunteers to fight the malaria infection. As a result, they were better able to control the malaria parasite,” according to physician-researchers Jona Walk and Charlotte de Bree.

"The so-called natural-killer (NK) cells of the innate immune system, in particular, reacted more quickly to the malaria infection in those with a BCG vaccination.” This is an important finding because NK cells remove malaria parasites from the blood, and can thus provide protection against the disease.

The future

Although the BCG vaccine did not provide full protection against malaria in this study, there are clear indications that 'BCG-trained immunity' can strengthen the defence against malaria. Because there is no malaria vaccine so far that provides complete protection, the researchers want to see if BCG could strengthen the effect of a vaccine. A vaccination strategy combining BCG and a malaria vaccine seems an attractive prospect.