Impact of the COVID-19 pandemic on contact tracing of patients with pulmonary tuberculosis

BACKGROUND: The COVID-19 pandemic could have negative effects on tuberculosis (TB) control. The objective was to assess the impact of the pandemic in contact tracing, TB and latent tuberculosis infection (LTBI) in contacts of patients with pulmonary TB in Catalonia (Spain). METHODS: Contact tracing was carried out in cases of pulmonary TB detected during 14 months in the pre-pandemic period (1 January 2019 to 28 February 2020) and 14 months in the pandemic period (1 March 2020 to 30 April 2021). Contacts received the tuberculin skin test and/or interferon gamma release assay and it was determined whether they had TB or LTBI. Variables associated with TB or LTBI in contacts (study period and sociodemographic variables) were analyzed using adjusted odds ratio (aOR) and the 95% confidence intervals (95% CI). RESULTS: The pre-pandemic and pandemic periods showed, respectively: 503 and 255 pulmonary TB reported cases (reduction of 50.7%); and 4676 and 1687 contacts studied (reduction of 36.1%). In these periods, the proportion of TB cases among the contacts was 1.9% (84/4307) and 2.2% (30/1381) (P = 0.608); and the proportion of LTBI was 25.3% (1090/4307) and 29.2% (403/1381) (P < 0.001). The pandemic period was associated to higher LTBI proportion (aOR = 1.3; 95% CI 1.1–1.5), taking into account the effect on LTBI of the other variables studied as sex, age, household contact and migrant status. CONCLUSIONS: COVID-19 is affecting TB control due to less exhaustive TB and LTBI case detection. An increase in LTBI was observed during the pandemic period. Efforts should be made to improve detection of TB and LTBI among contacts of TB cases.