Experimental vaccine promises to prevent TB

Tuesday, September 25, 2018 (HealthDay News) – Tuberculosis remains the deadliest infectious disease in the world, killing more than 1.6 million people a year. But the researchers say that a new vaccine could prevent half of the cases of serious illness in infected people who receive the vaccine.

"We found that the incidence of pulmonary TB was significantly lower" for people who received the experimental vaccine, called M72 / AS01, than for people who received a placebo vaccine, reported a team led by the Dr. Olivier Van Der Meeren.

He is responsible for clinical research at the drug maker GlaxoSmithKline, which funded the study with the pharmaceutical company Aeras. The results were published online on 25 September in the New England Journal of Medicine.

Although largely banned in richer countries, tuberculosis remains a widespread and often fatal respiratory disease in developing countries.

In fact, there were more than 10.6 million TB cases worldwide in 2016, noted Helen Cox and Valerie Mizrahi of the Wellcome Center for Infectious Diseases Research in Africa, Cape Town, South Africa. They wrote an editorial that accompanied the study.

Cox and Mizrahi also noted that TB was becoming resistant to many antibiotics and that "less than a quarter of the approximately 600,000 patients with MDR-TB were diagnosed and treated."

Thus, even an effective and poor vaccine would go a long way towards reducing the number of deaths worldwide. A vaccine – called BCG – exists, but its effectiveness is limited in adults already carrying a "latent" TB infection, explained the Van Der Meeren team.

Their new study was a phase 2 M72 / AS01 vaccine trial of nearly 3,600 adults in Kenya, South Africa and Zambia. All were infected with TB and had previously received the BCG vaccine.

In the trial, half of the participants received two injections of the newer vaccine, while the other half received placebo injections.

After an average of 2.3 years of follow-up, the researchers reported that 22 people in the placebo group had developed pulmonary TB, but only 10 of them had received the vaccine, a 54% reduction.

The vaccine appeared safe: while two-thirds of the recipients reported side effects, these were limited to injection site reactions or transient "flu-like" symptoms.

According to Van Der Meeren's group, the results are "promising" and "supportive". [the vaccine’s] in-depth evaluation "in a phase 3 trial.

An American expert acknowledged that safe and effective anti-TB vaccines are essential.

"Tuberculosis is still a global scourge and is easily spread by droplets that spread easily by talking, laughing and just being in the same room as a TB patient," said Dr. Len Horovitz. , New York City.

"The effectiveness of the vaccine was 54% in the prevention of tuberculosis in its own right," he said, and "although it may seem weak, many vaccines [the influenza vaccine, for example] have a comparable success rate. "

According to Mr Horovitz, "the elimination of half of the active cases is still significant, given the global prevalence of tuberculosis".

More information

There is more about tuberculosis at the American Lung Association.