Evaluation Of The Size Of Manotoux Test After BCG Vaccination On Infants And Children Attending The Paediatric Demonstration Unit At Kenyatta National Hospital, Nairobi, And The Maternal And Child Health Clinic At The Coast General Hospital, Mombasa

Abstract

This study has evaluated the Mantoux test in children who

were successfully vaccinated with BCG at birth as indicated by the presence of a scar (1). Groups of children were evaluated at progressive intervals 3, 6, 8, 12, 24, 36 and ·18months after immunisation. 'The.purpose of the study was firstly to determine

what size of positive reaction after Mantoux testing could be attributed solely to the immunisation and what size should be considered indicative of active infection and secondly to determine the appropriate age for booster BCG imrnunlsation, taking into account the waning of the Mantoux reaction with tirne, This study, using 1TU (one tuberculin unit) of PPD (purified protein derivative) has shown that 4 mm and 51l1m reactions were

most characteristic of BCG allergy in the children studied and that reactions beyond 10 mm were extremely rare. This would suggest that Mantoux reactions more than 10 mm in size in children below the age of 4 years should be considered as highly suspicious of tuberculous infection.

There was a significant reversion of the Mantoux test reaction to negative (66%)by one year of age, there being a greater number of negative than positive results, suggestions that booster BCG should be given at this age in areas of high prevalence of tuberculosis such as Kenya.