|Researchers developed a vaccine that effectively saved a number of patients with TB / Photo Credit: Shutterstock|
Researchers are moving closer to a new tuberculosis vaccine that could save millions of lives.
TB is among the top 10 killer diseases worldwide, specifically in developing countries, and the existing Bacille-Calmette-Guerin (BCG) vaccine was only proven to be effective for children under five for certain types of TB, medical health news website Medical Express reports. It adds that the BCG vaccine is ineffective against pulmonary TB—the most common form among adults and teens.
However, the "astonishing" results of the early trials can help scientists close in a game-changing vaccine for the killer disease. It comes as the world chases its target to reduce TB incidence to meet the 2020 milestones of the End TB Strategy.
"These results demonstrate that for the first time in almost a century, the global community potentially has a new tool to help provide protection against TB," Thomas Breuer, chief medical officer of GSK Vaccines, said in a statement.
A killer disease
TB spreads easier than it is curable. When a person with lung TB coughs, sneezes, or spits, they propel germs in the air, which can infect an otherwise healthy person.
The disease caused 10 million people to fall ill and kill 1.5 million others in 2018, the World Health Organization (WHO) says, adding that TB is also a leading killer of HIV-positive people, resulting in 251,000 deaths.
About 25 percent of the world's population has been found to have latent TB, which means that they are infected with TB bacteria but have yet to fall ill and cannot transmit the disease.
"People infected with TB bacteria have a 5–15 percent lifetime risk of falling ill with TB," the WHO says. "Persons with compromised immune systems, such as people living with HIV, malnutrition or diabetes, or people who use tobacco, have a higher risk of falling ill."
It adds that symptoms of active TB are mild for months when a person develops the disease, which delays treatment and further allows its transmission to other people. A person with active TB can infect up to 15 other people and without proper treatment, 45 percent of HIV-negative people and nearly all HIV-positive people with the disease will die.
There are still challenges in treating TB even though it is curable. This includes the development of drug resistance due to an incorrect prescription of anti-TB medicines, poor quality drugs, and patients stopping treatment prematurely.
What's more, the prevention of the disease with BCG only applies to children and certain types of TB—making teens and adults still vulnerable to infection.
Fortunately, the new clinical trials demonstrate promising results in the battle against the killer disease.
The new hope
A trial involving 3,575 adults in Kenya, South Africa, and Zambia led to the development of the new vaccine known as M72/AS01e. All of the participants were infected with latent TB, half of whom were treated with two doses of M72/AS01 and the other half with a placebo.
GlaxoSmithKline (GSK), the pharmaceutical firm that developed the vaccine with Aeras, said the vaccine had 50 percent effectiveness three years after it was given to the participants.
The efficacy is rather low compared to other established vaccines but with the prevalence of TB and the lack of other preventative measures, the M72/AS01 may prove to have a significant effect on the number of cases, according to science and technology magazine New Scientist.
"This is the first vaccine that has ever shown protection in previously infected individuals and so offers the potential for protection of vast numbers of people in endemic countries," said Barry Bloom, a recognized pioneer in global health from Harvard School of Public Health.
"Even if only 50 percent effective, with 10 million new cases and 1.4 million deaths annually, the number of lives that could be saved would be great," added Bloom, who was not involved in the study.
While the results show a promising future in TB treatment, larger trials would still be needed to better analyze the efficacy of the vaccine before it can be licensed for larger use.
Evaluating the effect and durability of the vaccine in TB prevention in a real-world setting would be the next vital step, Tim Wingfield, a TB expert at the Liverpool School of Tropical Medicine who was not involved in the trial, told the Telegraph.
He added that this would mean including other regions and different sub-populations, specifically those who are suffering from malnourishment or poverty.
|There's still a need to do a few more trials to better analyzed the treatment for TB / Photo Credit: Shutterstock|
The next stages of the trial are not yet confirmed, the GSK said, but there are talks about moving the vaccine forward. Conducting larger trials and securing regulatory approval will take years. Still, the results are promising.
Tens of millions of TB cases can be avoided and millions of lives can be saved if the vaccine is proven to be effective in larger trials. And as the researchers cautiously move to develop a vaccine for TB, other stakeholders should also do their part in preventing the spread of the disease and provide medication for those who need medications available today.