An Overview of Preventive Treatment for Latent Tuberculosis in Norway- 1996 to 2021

Abstract

Background: There is a lack of comprehensive nation-wide information on the preventive treatment for Latent Tuberculosis Infection (LTBI) in low-TB endemic settings. Objectives: To conduct a descriptive analysis and study the trends of the preventive treatment for LTBI, time to treatment after entry screening, and the impact of IGRA and shorter treatment regimens on the routines of preventive treatment in Norway over the past 25 years. Method: A descriptive nation-wide study based on the secondary data from the Norwegian Surveillance System for Communicable Diseases (MSIS). All the patients registered for LTBI treatment between the years of 1996 to 2021 were included in the study. Results:. Immigrants from very high TB incidence countries in the age group 18-39 were most frequently treated for LTBI. There was an increase in the number of entry screenings over the years , while contact tracing and immunosuppressive treatment continued at the same level. More treatments were offered after the replacement of Pirquet and PPD tests with the more specific IGRA test. The frequency of treatment also increased with the replacement of the Isoniazid monotherapy with shorter duration regimens of 3 months Rifampicin+Isoniazid daily and Isoniazid+Rifapentin weekly. 19% of adults received preventive treatment within 6 months and 56% within 12 months after entry screening, while for children, this period was 46% and 82%. The time to treatment shortened over the years. Conclusion: The study shows that there has been a substantial increase in preventive treatment with better diagnoses and better treatment regimens. However, more attention needs to be given to recording so that key information about the patients would not be missing.