The current Tuberculosis vaccine, BCG or Bacillus Calmette-Guerin, is only partially effective in preventing people from contracting TB. In a new report in the Lancet, an experimental vaccine showed little benefit when it was used as a booster in children after they had previously received the BCG vaccine. The BCG vaccine that is currently administered worldwide was introduced in 1921 and has not been modified since.
2,794 children aged four to six from South Africa were followed for two years, on average. Half of the children received the vaccination, MVA85A, and the other half received a placebo. Of those vaccinated there were 32 cases of Tb, compared with 39 with the placebo group, an effectiveness of around 17%. The protection from Tuberculosis was not seen as significant when the patients had received the vaccination.
The vaccine was designed to be used in conjunction with the BCG vaccine as a booster, hoping to bolster the body's defenses against infection. MVA85A has been in human trials for over ten years, and has been shown to be safe and induce a strong in adults, unlike in this trial where it was ineffective in children.
The MVA85A study was funded by AERAS, the Wellcome Trust and Oxford-Emergent Tuberculosis Consortium. AERA is a not-for-profit group that was organized to develop new TB vaccines and MVA85 was the most advanced vaccine that they assisted in developing.
Christopher Dye of the World Health Organization (WHO) and Paul Fine from the London School of Hygiene and Tropical Medicine jointly released a statement saying that although the results were disappointing they were 'not a terminal prognosis for MVA85A, or for any of the other tuberculosis vaccines in development.'
According to the Centers for Disease Control TB infections reached close to 9 million cases worldwide in 2011 and resulted in 1.4 TB related deaths.
Results were published in the Journal Lancet Online