HWN Suggests

The 100th Anniversary Of A Vaccine Against A Deadly Disease: Not A Cause For Celebration

TB’s burden is heavily borne by poorer communities, to the point that many in high-income countries think of TB as a disease of the past. Quite to the contrary, the disease remains an urgent concern today, having killed 1.4 million people in 2019. But despite its status as the top infectious disease killer prior to COVID-19, we still have only one vaccine for TB.

Developed in 1921, the BCG vaccine is effective only at preventing certain severe forms of TB in children (TB meningitis and disseminated TB); it is ineffective at preventing the most common form of TB, pulmonary TB, in adults. But despite these serious limitations, it remains the only TB vaccine in use to this day, a century…

read full article

Featured

 Is the 100-year old TB vaccine a new weapon against Alzheimer’s?

Studies suggest the BCG jab discovered a century ago could provide a cheap and effective way of boosting the immune system to protect people from developing the condition

Articles of Interest

Bacillus Calmette-Guérin (BCG) vaccine: A global assessment of demand and supply balance

The BCG vaccine market experienced several national stock-outs over the past decade across all regions, income groups and procurement methods. While the frequency has remained rather stable, duration of stock-outs increased in 2014–2015 due to manufacturing issues and attracted the attention of national, regional and global immunization stakeholders.

Children are silent victims of the ‘hidden epidemic’ of tuberculosis

Nations of the world came together in 2000 to make a solemn commitment to humanity to combat tuberculosis (TB), HIV/AIDS and other devastating diseases. This pushed governments to set up aggressive public health measures towards eradicating TB, but they have achieved only limited success. The moderate achievements have also been plagued by the paucity and poor quality of health data from lower-income countries.

History of BCG Vaccine

Humans have been infected with M. tuberculosis (Mtb) for millennia. TB infection is characterized by a complex immunologic response, which leads to a unique host-pathogen interaction therefore make it difficult to treat and control. Moreover TB is a poverty related disease and has severe social implications. The introduction of Bacille Calmette-Guérin (BCG) and chemotherapy in the past century marks an important advance in the history of tuberculosis (TB), which accounted for optimism to fight the disease especially in endemic area. To date, BCG remains as the most widely used vaccine worldwide and has been given to more than 4 billion individuals with astonishing safety records (1,2). Next to BCG, no other vaccines are available for treating TB and of the many new candidates in the pipeline none is close to market use.

Lasting Merit Found in a Tuberculosis Vaccine Invented a Century Ago

With the BCG vaccine, timing is crucial. The risk of dying from tuberculosis is high in infancy, wanes in childhood and then increases again after puberty.

Next-Generation Vaccines Based on Bacille Calmette–Guérin

Tuberculosis (TB), caused by the intracellular bacterium Mycobacterium tuberculosis (Mtb), remains a major health threat. A live, attenuated mycobacterium known as Bacille Calmette–Guérin (BCG), derived from the causative agent of cattle TB, Mycobacterium bovis, has been in clinical use as a vaccine for 90 years. The current incidence of TB demonstrates that BCG fails to protect sufficiently against pulmonary TB, the major disease manifestation and source of dissemination. The protective efficacy of BCG is on average 50% but varies substantially with geographical location and is poorer in those with previous exposure to mycobacteria.

TB vaccine BCG effective for twice as long as previously thought – study

Benefits of world’s only vaccine against tuberculosis were underestimated as new findings reveal it protects against the disease for at least 20 years.

Toward an Effective Tuberculosis Vaccine

Why has it been so hard to develop an effective vaccine for the disease?

What Have We Learnt about BCG Vaccination in the Last 20 Years?

A number of new tuberculosis (TB) vaccines have been or are entering clinical trials, which include genetically modified mycobacteria, mycobacterial antigens delivered by viral vectors, or mycobacterial antigens in adjuvant. Some of these vaccines aim to replace the existing BCG vaccine but others will be given as a boosting vaccine following BCG vaccination given soon after birth. It is clear that the existing BCG vaccines provide incomplete and variable protection against pulmonary TB.

Resources

Vaccine Knowledge

This vaccine gives protection against tuberculosis (TB) infection. It is 70-80% effective against the most severe forms of TB, such as TB meningitis. However, it is less effective in preventing the form of TB that affects the lungs.

WHO

The bacille Calmette-Guérin (BCG) vaccine has existed for 80 years and is one of the most widely used of all current vaccines, reading >80%of neonates and infants in countries where it is part of the national childhood immunization programme. BCG vaccine has a documented protective effect against meningitis and disseminated TB in children. It does not prevent primary infection and, more importantly, does not prevent reactivation of latent pulmonary infection, the principal source of bacillary spread in the community. The impact of BCG vaccination on transmission of Mtb is therefore limited.

CDC

BCG, or bacille Calmette-Guerin, is a vaccine for tuberculosis (TB) disease. Many foreign-born persons have been BCG-vaccinated. BCG is used in many countries with a high prevalence of TB to prevent childhood tuberculous meningitis and miliary disease. However, BCG is not generally recommended for use in the United States because of the low risk of infection with Mycobacterium tuberculosis, the variable effectiveness of the vaccine against adult pulmonary TB, and the vaccine’s potential interference with tuberculin skin test reactivity.