TB study reveals need for preclinical testing on animals
A 2013 South African trial involved vaccinating approximately 2,800 infants with the MVA 85A vaccine, meant to provide an added immune response in infants who had already received the existing TB vaccine (bacilli Calmette-Guerin, or BCG). The trial, however, did not work as promised.
In analyzing the results of the trial, Colorado State University's Department of Microbiology, Immunology and Pathology found that the BCG vaccine already inhibited the major strains of TB in the clinical trial site, which is why there was no noticeably improvement after the MVS85A vaccine was tested.
"It performed so well in the preclinical model, we determined that to boost its effects further was essentially impossible," Ian Orme, Colorado State University distinguished professor in the Department of Microbiology, Immunology & Pathology, said.
Orme said the study showed the need for preclinical testing on animal models, which is much less costly than testing new vaccines on humans.
"If you're going to test a new vaccine in a specific place, you should look at the local strains first and see if your vaccines are effective against the local strains people are catching," he said. "It is important to 'look before you leap,' and, unfortunately, that's not what happened in Cape Town."
Full findings of the study recently were published in the journal PLOS One.