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While vaccines have been successful in controlling some human diseases (eg: small-pox), millions of people continue to suffer and die from vaccine-preventable illnesses. For example, measles virus infects >10 million children every year causing between 0.5-1 million deaths. Although most measles-related mortality occurs in the developing world, even countries with high vaccination rates suffer periodic outbreaks as a result of poorly understood vaccine failure. We are involved in a number of field-based, basic studies in which we hope to identify the factors responsible for poor measles vaccine efficacy in the developing world (eg: Peru, Haiti) and vaccine failure in the developed world.

Pertussis (whooping cough) is another pathogen which continues to kill hundreds of thousands of children despite the availability of a vaccine for more than 30 years. The efficacy of the pertussis vaccine currently used in Canada is only 40-50%. We do not understand what constitutes 'effective' immunity against pertussis hence we are limited in our ability to develop more successful vaccines. We have developed a variety of tools for measuring humoral and cellular immune responses to vaccines which we are applying in field evaluations of new vaccines directed against both measles and pertussis.

Human pathogens can do damage either directly or indirectly. Measles infection is associated with a range of immunopathologic conditions. Poorly understood mortality occurs for months to years after exposure to wild-type measles and even to high titers of vaccine-strain measles virus. We are involved in several field- and lab-based studies of the immuno-pathologic potential of measles.

Another area if interest is the role of nutrition in modulating immunity to infectious agents. We are involved in three field studies examining nutritional factors in the horizontal transmission of HIV (Zimbabwe), in measles vaccine responses (Peru) and in the modulation of Chagas Disease expression (Brazil)