6 YEARS EXPERIENCE WITH THE DISCONTINUATION OF BCG VACCINATION .4. PROTECTIVE EFFECT OF BCG VACCINATION AGAINST THE MYCOBACTERIUM-AVIUM-INTRACELLULARE COMPLEX

Setting: In 1986, mass BCG vaccination of newborns was discontinued in an extensive territorial sample of neonates in the Czech Republic (30 000 infants annually). The non-vaccinated children have since been tu berculin tested at two-year intervals; those with continual or repeate d intensive contact with animals in households or on farms were also t ested with Mycobacterium avium intracellulare complex sensitin in addi tion to tuberculin. Objective: Within the frame work of the surveillan ce programme the incidence of infection and disease caused by M. avium intracellulare complex (M. avium complex) was evaluated and the prote ctive effect of BCG vaccination analysed. Design: In 1986-93, out of 1 90 874 non-vaccinated children, 36 were found to be infected by M. avi um complex; 27 of them developed disease, i.e. mycobacteriosis other t han tuberculosis (MOTT). Results: The annual risk of infection with M. avium complex was 4.8/100 000 children per year, of whom 3.6/100 000 developed mycobacteriosis. 24 patients suffered from swelling of cervi cal lymph nodes, 2 of mediastinal lymph nodes and one child had the di sease localized both in cervical and mediastinal lymph nodes. The dise ase was verified bacteriologically in 9 children. Most of the diseased children had impaired immunity; a marked skin reactivity of M. avium complex sensitin was present in all infected children. Animal sources infected by M. avium complex were detected in 5 cases. Another 14 chil dren also had close contact with animals but without proven M. avium c omplex infection. Conclusion: In non-BCG vaccinated children the incid ence of lymphadenitis caused by M. avium complex was considerably high er than in vaccinated children. BCG cells possess antigenic determinan ts which confer protective immunity probably both against M. tuberculo sis and against M. avium complex infections. It may thus be assumed th at BCG vaccination protects both against pathogenic tubercle bacilli a nd M. avium complex. This should be taken into consideration before re commending discontinuation of mass BCG vaccination of newborns in area s with a high prevalence of M. avium complex infection.