Impact of COVID-19 pandemic on latent and active tuberculosis treatment registrations in Montreal, Canada: a retrospective study at the Montreal Chest Institute



We sought to assess the effect of the COVID-19 pandemic on registrations for treatment of latent tuberculosis infection (LTBI) or active tuberculosis at the Montreal Chest Institute (MCI), a specialized referral center in Montreal, Quebec, the city with the highest number of COVID-19 cases and deaths in Canada. 


We used data from the MCI Tuberculosis Clinic E-Chart, in which all patients seen by our nurses to initiate LTBI or active tuberculosis treatment have been registered since November 26, 2005. Separately for LTBI and active tuberculosis, we compared the number of registrations per week since the COVID-19 public health emergency (“COVID era”) to the number per week prior to this (“pre-COVID”). We counted registration dates as COVID era if they fell within or after the week the Quebec government declared a public health emergency (Week 11 of 2020), and pre-COVID if they occurred prior. Using Poisson regression, we estimated rate ratios comparing rates of registrations (number registered per week) in the COVID and pre-COVID eras, adjusting for year, and week of the year. 


Between November 26, 2005, and June 23, 2020 (date of database query), we registered 6849 patients for LTBI treatment (6801 pre-COVID, 48 COVID era) and 902 for active TB treatment (890 pre-COVID, 12 COVID era). Figure 1(a) shows the average number of LTBI treatment registrations per week in the pre-COVID (blue) and COVID (red) eras, and Figure 1(b) shows this for active TB. Compared to pre-COVID, there was a 59% reduction in the registration rate for LTBI treatment during the COVID era (rate ratio=0.41 p<0.0001), and a 24% reduction for active TB treatment (rate ratio=0.76, p=0.37).   


There is an urgent need to implement strategies to mitigate the negative impact that the COVID-19 pandemic is having on LTBI and active TB management in Montreal, Canada.

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