Tuberculosis vaccine fails in tests on infants
Philadelphia, PA, United States (4E) – An experimental tuberculosis vaccine failed to prevent infection and progression of the disease during its trial on 2,800 South African babies, according to the drug’s developer.
The ineffectiveness of the MVA85A vaccine was revealed in an online report by the medical journal The Lancet on Monday.
An official of the Rockville, Maryland-based non-profit biotechnology company Aeras, which developed the vaccine, said the vaccine only failed on infants four to six months old. Aeras head Tom Evans said the MVA85A is not going to be ineffective on adults.
American, British and South African researchers from the University of Oxford and the University of Cape Town conducted the clinical trial of the vaccine on infants in Cape Town from 2009 to 2011. The vaccine supposedly works by stimulating production of antimicrobial gamma-interferon substance to boost the limited immunity given by the standard TB shot called Bacille Calmette-Guerin or BCG. BCG does not protect from TB infection but reduces the chances of the disease spreading to other organs.
Half the infants in the clinical trial were immunized with MVA85A while the other half was injected with placebo. Within the next two years, 13 percent of those vaccinated were infected with TB and 2 percent developed the disease. About 12 percent of the other babies given placebo also got infected with TB and 3 percent developed a full-blown disease.
The World Health Organization counted 8.7 million people with TB in 2011. Of the number, 1.4 million died. One-third of the world’s population are carriers of the lung disease that is spread by a bacterium in the air.