A study was undertaken to explore the knowledge, attitudes and perception of TB and their influence on the adherence to preventive therapy for TB. During 1997, 24 subjects were interviewed by using a semistructured questionnaire which included demographic details, background information on TB, knowledge and perception of TB and chemoprophylaxis. The persons were interviewed in the outpatient clinic in London at the start of the treatment and at monthly intervals thereafter. They were given INH daily for 6 months. The data was analysed descriptively and thematically. The outcome was assessed ? 6 months after the start of preventive treatment.

The sample was representative of age, ethnicity and previous BCG vaccination status. The study results revealed that 63% were aware of TB before starting chemoprophylaxis indicating a medium level of awareness. None mentioned health centre as the source of information. Knowledge of TB was gained outside the family. About 63% of them knew about transmission of the disease but few symptoms of active TB were recognized. Most (92%) were aware that TB was infectious. The perceived threat from TB was high (71% believed that TB was potentially fatal), although the estimated risk was low. Over half of the subjects (66.6%) suggested that TB was preventable. Knowledge of preventive therapy exceeded the general knowledge of TB, although the latter was associated with better adherence. Most denied knowledge of the risk of hepatitis from isoniazid. Defaulters failed to attend their first appointment, attributed more side effects to isoniazid and perceived a longer waiting time in clinic. The rate of non-attendance for appointment at the TB clinic was high.

The study has shown that there is an important lack of knowledge of the symptoms of TB. A better general knowledge of TB is more helpful than merely an understanding of the treatment regimen in promoting adherence. It recommends a single daily tablet, prior warning of dizziness and an open discussion of the problems of keeping to treatment for 6 months encouraging adherence to preventive treatment.