Hopes of wiping out pulmonary tuberculosis suffered a major setback today, as the most promising new vaccine was shown to do little to protect children.
Pulmonary TB is most common form of the disease among adolescents and adults, killing 1.4 million people around the world each year. The MVA85A vaccine candidate, developed by British researchers, had shown positive results in stimulating high levels of immune response in adults during earlier trials.
But scientists spoke of their disappointment after the potential vaccine failed to replicate this success in its first field trials on children.
The findings of the research conducted in South Africa, published in The Lancet, have dealt a blow to the fight against TB. The only existing vaccine, BCG, was created 90 years ago and does not prevent pulmonary TB.
Helen McShane from the University of Oxford, who helped develop the vaccine, said: “The [MVA85A] vaccine induced modest immune responses against TB in the infants, but these were much lower than those previously seen in adults, and were insufficient to protect against the disease.”
Of 2794 healthy, BCG-vaccinated infants aged 4-6 months, 1,399 infants received the drug while 1,395 were given a placebo. Three years after treatment, researchers found 39 cases of TB in the placebo group and 32 in the MVA85A group. Christopher Dye, a director of health information at the World Health Organisation, told The Independent there was “still hope”, despite the disappointing results.
The “big target” in the war against TB is pulmonary lung disease in adults, he said. “To see the effect on children is important and gives interesting results, but it leaves open the question of how a vaccine of this sort would be able to protect adults, who are the greatest victims of pulmonary lung disease around the world.”