This doesn't cause the reactions associated with BCG and works on the principle that all mycobacteria, pathogenic or not, share certain antigens and hence that an antibody raised to a common component will protect against all pathogenic mycobacteria. There is therefore no advantage at all in using the pathogenic M. tuberculosis to generate an immune response. A further potential advantage is that M. vaccae can be given to persons already harbouring tuberculosis with the prospect of preventing the reactivation which is the cause of most clinical tuberculosis. M. vaccae has already been used as an additive to BCG to enhance the effectiveness of the latter against leprosy, and as a booster in children with BCG scars or who tested tuberculin-positive. Although campylobacter was first recognised in 1913, it was only appreciated as a pathogen in the 1970s.
Many infections are totally asymptomatic.
Campylobacter enteritis is characterised by diarrhoea, abdominal pain, fever, nausea and vomiting. It generally lasts two to five days and only rarely more than ten. There is an initial phase of fever and malaise which lasts about 24 hours and is succeeded by watery diarrhoea. Abdominal pain is sometimes a prominent feature, as is blood in the stools, and bacteraemia may occur. Recovery may be prolonged and relapses can occur, particularly in adults.