HMN 2026: How Flu infection may weaken tuberculosis defenses by disrupting key immune pathways

New research from Imperial College London suggests that infection with the influenza virus may leave people more susceptible to tuberculosis. The findings suggest that seasonal flu vaccines could offer a potential new strategy for preventing and controlling tuberculosis in regions around the world where prevalence is high and people are at high risk.

Around 11 million people each year fall ill with TB, and it remains one of the leading causes of death from infectious disease globally.

Using blood samples from Imperial’s human challenge studies program, where healthy volunteers are infected with influenza virus under controlled conditions, scientists showed that infection with influenza virus inhibits immune pathways that control the growth of the TB mycobacterium.

The findings, published in Nature Communications, suggest that seasonal flu vaccines could offer protection against TB in regions where TB is highly prevalent, such as India, Indonesia and South Africa.

Dr. Claire Broderick, clinical lecturer in the Department of Infectious Disease and first author of the paper, said, “This study provides the first direct evidence in humans that influenza infection impairs the body’s ability to control the growth of the bacteria responsible for tuberculosis.

“What this means is that a seasonal virus could weaken our ability to fend off TB—which remains a major cause of illness and death around the world. Thanks to the invaluable data generated through these human challenge studies, we’ve been able to pinpoint the immune pathways important for controlling TB infection that are disrupted by influenza.”

Using human challenges to solve infection problems

Human challenge studies are a form of medical research in which volunteers are intentionally given an infection in a safe way with health care support. These studies allow researchers to investigate and understand the onset and development of disease in a controlled environment. They also allow scientists to tease out complicated interactions and find potential targets for new vaccines or treatments that cannot be seen in patients who are infected naturally.

In this study, scientists used blood from participants before and after they were infected with influenza. The blood samples were then infected with a form of TB mycobacterium, and the level of growth of the mycobacteria was observed.

Scientists found that participants who developed influenza infection showed significantly higher mycobacterial growth in their blood compared with levels before infection and compared with participants who remained uninfected with influenza. The loss of control was found to be driven by the disruption of critical immune pathways, specifically type 1 interferon signaling, which has previously been shown to be essential for containing the spread of TB.

Flu vaccines for TB

With some TB strains becoming increasingly resistant to antibiotics (MDR-TB), flu vaccination could provide a cost-effective means of strengthening protection against this growing public health threat.

Broderick added, “What we need now is support for large-scale trials to test this and see how effective this approach could be. Given the huge burden from TB, it’s crucial we explore new strategies to control the disease.”

The content is provided for information purposes only.