TB Vaccine

New Intravenous TB Vaccine Strategy Holds Promise for People with HIV

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A breakthrough TB vaccination strategy developed by scientists at the University of Pittsburgh School of Medicine could potentially save the lives of hundreds of thousands of people living with HIV worldwide. TB is the leading cause of death among individuals with HIV, with one in three people living with HIV dying from TB.

The results of the study, published in Nature Microbiology, demonstrated that when administered intravenously, the Bacille Calmette-Guérin (BCG) vaccine, which is currently the only commercially available vaccine against TB, effectively prevented lung infection in monkeys infected with the simian form of HIV, called SIV. This is significant, as the vaccine is not recommended for individuals with HIV.

TB is caused by the bacterium M. tuberculosis and primarily affects the lungs. It is the second-leading infectious killer globally, with 1.6 million deaths attributed to TB each year, including nearly 200,000 among individuals with HIV, according to the World Health Organization.

The BCG vaccine, which has been in use for a century, is made from a weakened form of M. bovis, a bacteria closely related to M. tuberculosis. Although widely used and administered to infants and children via injection, it provides minimal protection against M. tuberculosis, particularly lung infections.

In a groundbreaking study published in Nature last year, researchers from the University of Pittsburgh and National Institutes of Health found that intravenous administration of the BCG vaccine provided a high level of protection against TB, including lung infections, in monkeys.

Building on these findings, the recent study took a unique approach. After administering the BCG vaccine intravenously, the researchers subsequently administered antibiotics to eliminate all live bacteria in the vaccine. Their objective was to allow sufficient time for the vaccine to stimulate the immune system to protect against TB infection while minimizing the risk of disease caused by the weakened bacteria in the vaccine in immunocompromised monkeys.

The gamble paid off. None of the animals exhibited any sickness from the BCG vaccine, and most importantly, 75% of the SIV-infected monkeys that received intravenous BCG vaccination followed by antibiotics were able to successfully fight off TB infections. The vaccine also protected all monkeys without SIV infection. The only instances where the vaccine failed to prevent TB were observed in monkeys with advanced SIV disease, where the immune cells had been depleted by the virus.

While it may not be feasible to administer the vaccine intravenously to individuals with HIV and then expect them to return for antibiotic treatment, especially in low- and middle-income countries, the scientists plan to further explore the safety of intravenous BCG administration without antibiotics. They also intend to evaluate new BCG vaccines in development that self-destruct before causing disease in immunocompromised individuals, while still effectively preventing TB.

TB and HIV are closely intertwined epidemiologically, particularly in regions with limited access to healthcare and where HIV goes undiagnosed or untreated. Therefore, a viable TB vaccination strategy is crucial in saving countless lives each year. The researchers are optimistic that their study represents a significant step in that direction.

In conclusion, the development of an intravenous TB vaccination strategy that effectively prevents TB infections in individuals with HIV could have a profound impact on public health. Further research and clinical trials are necessary to explore alternative methods of administration and to develop more effective vaccines. Implementing a realistic TB vaccination strategy is imperative in reducing the global burden of TB and HIV co-infection and ultimately saving lives.

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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it