Impact of the COVID-19 pandemic on the epidemiology and clinical course of tuberculosis: expected and paradoxical consequences
摘要
This study included tuberculosis (TB) patients from high-burden Russian regions of Siberia and Far East. We aimed to assess the impact of the COVID-19 pandemic on the genotypic structure of Mycobacterium tuberculosis population and on epidemiology and clinical course of tuberculosis in TB and TB/COVID-19 coinfected patients.
MethodsA total of 456 M. tuberculosis isolates were studied and submitted to drug susceptibility testing and genotyping. The modern Beijing genotype and its main Russian epidemic and endemic clusters (B0/W148 and Central Asian/Russian), and ancient Beijing sublineage were detected by PCR assays targeting specific molecular markers. Non-Beijing isolates were spoligotyped and compared to SITVIT2 database.
ResultsMore than 80% of strains belonged to the Beijing genotype. Among Beijing strains, genetic clusters B0/W148 and Central-Asian/Russian (94–32) accounted for 94.2% in the pre-pandemic period and 96.6% during the pandemic in the TB group, and 81.5% of TB/COVID-19 group. Moreover, in the pre-pandemic TB group, the ratio of B0/W148 and 94–32 was almost 1:1 (49.7:44.4%), during the pandemic—1.5:1.0 (57.9:38.8%), while in the TB/COVID-19 group, the ratio shifted in favor of the 94–32 cluster and became 1:2 (31.8:65.9%). In TB/COVID patients, the structure of clinical forms shifted from chronic forms (fibrous cavernous TB, tuberculoma) to forms with more active inflammatory and destructive-inflammatory reactions (infiltration, dissemination, cavernous TB). In TB (without COVID-19-coinfection) group, the effectiveness of TB treatment during the pandemic decreased by 20.6% (p = 0.002). In the TB/COVID-19 group, the effectiveness of treatment increased, likely due to the predominance of the less frequently MDR Beijing 94–32 cluster in this group. A statistically significant positive correlation was shown between the detection of the 94–32-cluster and the effectiveness of treatment of patients with TB/COVID-19 (Q = 0.56, p = 0.006).
ConclusionsOur results are consistent with the reportedly higher ability of Beijing B0/W148 strains (compared to Beijing 94–32) to acquire resistance to anti-TB drugs, their increased virulence and transmissibility. Thus, the seemingly paradoxical, milder clinical course of TB in patients who further developed COVID-19 is explained by a shift in the ratio of M. tuberculosis subtypes due to syndemic interaction between the two epidemics.