New tuberculosis vaccine: the first pancake lump
Tuberculosis vaccine trials have failedBBC
These were the first major trials of the vaccine on children since the creation of the vaccine, known as the Calmet-Guerin bacillus. This anti-tuberculosis vaccine was created in 1921 from a strain of weakened live cow tuberculosis bacillus and is referred to as BCG in medical usage.
The bacillus of Calmet-Guerin only partially inoculates against the bacterium that causes tuberculosis. That is why international groups of scientists continue to work on the development of new vaccines.
The results of their latest tests were published by scientists in the Lancet medical journal.
The latest development, called MVA85A, failed to protect children who had already been vaccinated with BCG from infection.
About 2.8 thousand healthy infants aged four to six months participated in the trials conducted in South Africa. Half of them received MVA85A, and the rest received a placebo. Then the doctors monitored the children's health for almost two years.
As a result, tuberculosis was diagnosed in 32 vaccinated children and in 39 who received a placebo. This difference is too small to recognize the remedy as effective.
Disappointing resultsDesigned to strengthen the immune response of patients after BCG vaccination, the MVA85A vaccine has been tested on humans for a decade, and it has proven its safety and a high level of immune response among adults.
Professor Helen McShane of Oxford University, who was involved in the development of the vaccine, said that the drug "causes a slight immune response to the bacterium that causes tuberculosis in children, but these indicators are significantly lower than previously demonstrated in tests on adults, and insufficient to protect against the disease."
"These are the first trials of the effectiveness of a new TB vaccine after the Calmet-Guerin bacillus, which in itself is an important step, and now we, like other researchers, can learn a lot from this study and the data obtained," she added.
In an editorial accompanying the Lancet article, Christopher Dye of the World Health Organization and Paul Fine of the London Institute of Hygiene and Tropical Medicine complain about the disappointing results, but do not consider them the final verdict for MVA85A or other TB vaccines under development.
The development and testing of MVA85A was funded by the American organization AERAS, engaged in the development of effective methods of tuberculosis treatment, and the British Wellcome Trust Foundation through the Oxford-Emergent Tuberculosis Consortium venture fund, created by Oxford University and Emergent BioSolutions.
MVA85A was the most advanced of the six candidate vaccines that AERAS helped develop.
According to WHO, 8.7 million people worldwide are diagnosed with tuberculosis every year, and about 1.4 million cases of the disease end in death. Tuberculosis is also the most common cause of death among HIV-infected people in South Africa.
According to Richard White, an epidemiologist at the London Institute of Hygiene and Tropical Medicine, about 12 new TB vaccines are currently being tested on humans, the first of which was MVA85A. Almost 50 more candidate vaccines are currently being tested in the laboratory.
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