July 24, 2021

The tuberculosis vaccine makes its first effective jump in a century | Society

The tuberculosis vaccine makes its first effective jump in a century | Society

A new vaccine against tuberculosis gives the first effective jump in a century and is called to be the star of the congress on the disease that begins this Wednesday in The Hague (Holland). The drug has finished phase II, that is, its safety and efficacy have been proven in a group of volunteers and, according to the results published in the journal New England Journal of Medicine, Its effectiveness is 54% in adults previously exposed to the bacteria. It is the population most affected by the disease and in which the old prophylaxis works the worst.

The BCG vaccine, 1921, based on the bacillus Calmette-Guérin, remains the only one available almost a century later. In general terms, it provides 30% protection, although it is more effective in newborns. The rate is so low that many countries, such as the US, do not recommend it. Because it is not a country with a high incidence of this disease either.

"It could help save half of the 1.8 million deaths per year and avoid hundreds of thousands of sick people," Marie-Ange Demoitie, a researcher at the GSK laboratory, told The Hague on Tuesday that together with IAVI (International Access to Vaccines) test the prototype. The drug M72 is the first development in this field that is close to reaching the patient since 1921.

Of the three major infections in the world, AIDS, malaria and tuberculosis, the latter is the most frequent by far and its reduction hardly progresses because it remains latent for many years and the bacteria develops more and more strains more resistant to current medications. There are about 10 million cases a year and affects all continents. "It's a disaster that kills more than 4,500 people a day," said Dutch Thomas Ottenhoff, co-chairman of the conference on Tuberculosis Science that precedes the congress itself.

According to Demoitie, the vaccine is being tested in Zambia, Kenya and South Africa, in 3,200 people without HIV in a double-blind trial (half receive placebo and not even their doctors know who is taking the real drug). The trial is missing phase III, the large-scale test.

More tests

In addition, as the researcher said, it is being tested "in the most risky population, that is, in the most exposed people who were not protected by the previous vaccine". Mark Hatherill, of the South African Initiative for a Tuberculosis Vaccine, has also pointed out that it will have to be tried "in other groups and other places. Also in uninfected people. "

It is possible, too, that the vaccine that finally reaches the market is not exactly this, but an improved version. For example, it will be necessary to ensure that the response it provokes is maintained over time, Hatherill pointed out, and that ideally it should be administered only once.

60,000 cases in Europe

Europe registered about 60,000 cases of tuberculosis in 2016. They are few for the 10 million annual in the world, but it is where you have a better perspective, with reductions of 4.6% year-to-year this decade, but that will not be enough to reach the goal of eradication in 2030, warns the European Center for Disease Control (ECDC).

The Netherlands is an example of how the situation evolves. In the twenties of the last century the union of workers of the diamond workshops opened the sanatorium for tuberculosis of Zonnenstraal, an imposing modernist complex that offered the medicine of the time: pure air, sun and healthy food waiting for the patient he will recover alone. The country had about 30,000 cases per year. That sanatorium closed in the fifties. But, now, the Dutch Ministry of Health is building the center of Beatrixoord, near Groningen.

The country only registers 1,000 cases of tuberculosis per year (Spain is above 4,000), but extremely resistant. The majority of those admitted to Beatrixoord are foreigners. In Europe they represent 30%. But do not get sick, warn doctors from the center. They are people who in childhood were exposed to the bacteria and in the adult stage they develop the infection due to the conditions in the host country or the hardships of the trip.

The latter is key. In many countries, the population is in contact with the tuberculosis bacterium, but that does not mean that it acts, but remains latent until external conditions such as age, immunological, nutritional problems, stress, bring it to the surface. It is estimated that approximately one third of the population is in that situation.

The vaccines that are being tested are directed, therefore, to people who were exposed to the bacteria in their childhood but who are at risk of developing the infection later. The M72 is one of them, and it is novel because it is a preparation to which genes of the tuberculosis cover have been introduced and an adjuvant for the immune response to be more potent.

South Africa is also testing new ways of using the veteran BCG, also in a population that has already been exposed to the bacteria, as a kind of immune reminder that repeats itself over time. To doubts about the effectiveness when the vaccine reaches real life, Lucica Ditiu, Executive Director of the Stop TB Partnership, and enthusiastic representative of patients, adds another problem: "TB has never been a priority." "It can not be that when the Ebola crisis there was a vaccine a year and a half and we have a century waiting for a new one," he said. "We have heard the great hope that it represents, now we need to take it to reality."

According to the calculations of Ditiu, to improve the attention of people with tuberculosis from all over the world would require 2,200 million dollars (some 1,900 million euros), but only one third (some 700 million) is available. "Many of the heads of government who attended the UN's high-level meeting on tuberculosis in September signed their commitments [para emprender la erradicación de la enfermedad] without knowing what they were doing. They would have signed the same as in 2023 they were going to fly ", adds the activist.

Whether the M72 is final or not, "we are in a moment of change the scenario," says Ann Ginsberg, of IAVI. Ditiu rivets: "It would be a disaster if we lost this opportunity".


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