L7 Impact of National lockdown for SARS-CoV-2 pandemic on incident tuberculosis and transmission

Abstract

<h3>Introduction</h3> The nationwide lockdown for COVID-19 and ongoing mitigation measures are having a significant impact on healthcare delivery for other disease including tuberculosis (TB). Leicester has faced a particularly prolonged period of disruption after imposition of local lockdown measures within 7 weeks of the national lockdown. <h3>Objectives</h3> To evaluate the impact of the national lockdown and post-lockdown periods on tuberculosis presentation and transmission in Leicester, UK. <h3>Methods</h3> We performed retrospective analysis of all notified tuberculosis cases and their contacts comparing the pre-lockdown period (January 2019 – March 2020) with lockdown and post-lockdown periods (April –Sept 2020). AFB smear status, Xpert DNA load, culture status, time to culture positivity, CXR severity scores, hospital admission rate and proportion of screened contacts identified with latent tuberculosis infection (LTBI) were reviewed. Data was extracted from hospital systems. Statistical analyses used SPSS (v.26). <h3>Results</h3> 307 index cases (146 pulmonary) and 460 family contacts of pulmonary TB were included for analysis. Overall, TB incidence in 2020 has been lower than 2019 (144 vs. 129 cases from Jan – Sept). There has been a marked fall in cases during the lockdown with no comparable rebound increase post-lockdown (figure 1). Comparing the pre-lockdown period with the period since lockdown, there has been a non-significant increase in duration of symptoms before diagnosis (15.7 vs. 17.7 weeks, p=0.81) and fall in hospital admission rate (47.6% vs. 33.3%, p=0.117). For pulmonary TB, there has been a significantly higher proportion with smear positive disease (24.2% vs. 42.1%, p=0.040) and a higher proportion with microbiological confirmation of disease (by culture: 73.7% vs. 81.1%; by Xpert: 77.5% vs. 91.4%). However, the time to culture positivity and CXR disease burden are comparable before and after the lockdown. There has been a mean reduction of 0.5 persons per index case requiring contact screening (4.4 vs. 3.9) and no change in the proportion identified with LTBI (29%). <h3>Conclusions</h3> The impact of lockdown measures on TB remains unclear. Early data here suggests presentation of more infectious cases. However, fewer active TB have been diagnosed since the lockdown, raising the possibility of an increasing undiagnosed burden of TB in the community.