Heaf test

Abstract: The results of a prevalence survey undertaken during 1974 are presented. A stratified 3-stage sampling technique was used to select 3 789 people from 10 randomly chosen sites in KwaZulu. One Heaf test and 2 Mantoux tests were performed on each of 1 769 children under 18 years of age, of whom 28,7% were found to have BCG scars. Of the radiographs taken of persons 15 years of age and older, 893 were found to be negative, 25 (2,7%) disclosed active tuberculosis (TB) and 3 (0,3%) miliary TB. Of the 1 136 sputum specimens collected and examined by fluorescence microscopy, 15 (1,3%) were found to be positive and 9 of them were confirmed by culture. Culture of 1 149 specimens yielded 9 (0,8%) isolations of Mycobacterium tuberculosis and 17 strains of other mycobacteria. The annual rate of infection was calculated at 1,4% by applying Styblo's epidemiological model, and a downward trend was indicated. A follow-up survey after 5 years is needed to confirm this trend.

Abstract: BACKGROUND BCG vaccination using the multipuncture device (the Heaf gun) is recommended in the UK for infants and very small children only. The aim of this study was to investigate the rate of conversion of the tuberculin test, the safety and acceptability of BCG vaccination using the multipuncture device and to compare it with the conventional intradermal method in schoolchildren. METHODS Schoolchildren attending schools in Tower Hamlets who were eligible for BCG vaccination were tuberculin tested using the Heaf gun. Those with grade 0–1 reaction were randomised to receive BCG vaccination using either the multipuncture or the intradermal method. The site of BCG vaccination was inspected after eight weeks for inflammatory changes and scarring. A questionnaire about pain and inflammation at the site of vaccination was completed. The Heaf test was repeated at eight weeks and its results were assessed by an examiner unaware of the results of the previous Heaf test and the method of BCG administration. The Heaf test conversion was deemed to have occurred if there was a change of at least one grade in the response. RESULTS One hundred and sixty nine children (83 girls) of mean age 11.8 years completed the study, of which 81 received BCG by the multipuncture method. The Heaf test did not convert in 22 of 81 (27.2%) receiving BCG by the multipuncture device compared with six of 88 (6.8%) who received the vaccine by the intradermal method (odds ratio 0.2, 95% confidence interval 0.07 to 0.55). The BCG scar was visible in all children who had intradermal BCG compared with 67 of 81 (81.8%) of the multipuncture group. The multipuncture method was less painful and caused fewer inflammatory changes than the intradermal method. CONCLUSIONS In schoolchildren the multi- puncture device for administering BCG caused a lower rate of tuberculin conversion as measured by the Heaf test and less of an inflammatory response than the intradermal method. The method needs to be modified before it is applied on a wider scale to schoolchildren.

Abstract: Heaf tests were performed in 834 adults and children seen during one year in a tuberculosis contact clinic in Edinburgh. All subjects with a past history of tuberculosis, or who subsequently developed evidence of tuberculous infection and 63 subjects of Asian origin were excluded to leave 749 ‘healthy’ adults and children broadly representative of the local causasian population. All Heaf tests in 178 children without BCG vaccination were negative or grade I whereas 16 (73%) of the 22 children with a history of previous BCG vaccination were positive grade I or II. A strongly positive Heaf test (grade III–IV) in any child with or without previous BCG vaccination seen as a tuberculosis contact implies recent infection and merits consideration for chemoprophylaxis or prolonged follow-up. Two hundred and seventy adults without previous BCG vaccination showed an increasing incidence of strongly positive Heaf tests (grade III or IV) with age reaching a peak of 55% in the 45–65 age group; beyond the age of 65 this fell to 37%. Two hundred and eighty-one adults with previous BCG vaccination showed significantly more Heaf grades I and II, fewer negatives and fewer strong positives than the unvaccinated group. A strongly positive Heaf test (III–IV) is a frequent finding in a healthy adult and has little discriminatory value in the diagnosis of active tuberculosis infection in Edinburgh, and by implication elsewhere in the United Kingdom. Positive tuberculin tests should be viewed in the context of the tuberculin profile of the local population.

Abstract: OBJECTIVE--To determine the efficiency of tuberculosis contact tracing in South Glamorgan 1987-9. DESIGN--Review of records of contact tracing clinic and of data from the Mycobacterium Reference Unit. The clinic's practice was compared with 1983 British Thoracic Society's recommendations. SETTING--Health authority tuberculosis control programme. MAIN OUTCOME MEASURES--Proportion of contacts screened, follow up attendance rates, number of secondary cases detected, and quality of record keeping. RESULTS--101 index patients and 611 contacts were identified. 596 (97.5%) contacts were screened, of whom 139 should not have been. Of 356 contacts requiring a Heaf test, 237 were tested, seven refused the test, and 112 had chest radiography without a Heaf test. 95 contacts were unnecessarily tested. 87 contacts had chest radiography unnecessarily and seven should have had radiography but did not. 34 contacts were given follow up appointments inappropriately and seven were overlooked for follow up. Tuberculosis was diagnosed in five asymptomatic contacts, all at initial screening and all close contacts of index patients with pulmonary disease. CONCLUSION--Inadequacy of data, non-adherence to contact tracing guidelines, and failure to define the term highly infectious index case resulted in many contacts being unnecessarily screened or followed up. IMPLICATIONS--The efficiency of tracing contacts would be improved by specifying smear results and ethnic origin of the index case on the notification form, clearly classifying contacts as close or causal, and clearly defining the term highly infectious.