Low prevalence of nirmatrelvir-ritonavir resistance-associated mutations in SARS-CoV-2 lineages from Botswana

Abstract

BACKGROUND We evaluated naturally occurring nirmatrelvir-ritonavir (NTV/r) resistance-associated mutations (RAMs) among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains from Botswana, a country with no NTV/r use to date, in order to recommend the usage of the agent for high-risk patients with coronavirus disease 2019 (COVID-19). METHODS: We conducted a retrospective analysis using 5254 complete SARS-CoV-2 sequences from Botswana (September 2020–September 2023). We evaluated the mutational landscape of SARS-CoV-2 3-Chymotrypsin-like protease (3CLpro) relative to the highlighted list of RAMs granted Food and Drug Administration Emergency Use Authorization in 2023. RESULTS: The sequenced 5254 samples included Beta variants of concerns (VOCs; n = 323), Delta VOCs (n = 1314), and Omicron VOCs (n = 3354). Overall, 77.8% of the sequences exhibited at least 1 polymorphism within 76/306 amino acid positions in the nsp5 gene. NTV/ rRAMs were identified in 34/5254 (0.65%; 95% CI, 0.43%–0.87%) and occurred at 5 distinct positions. Among the NTV/r RAMS detected, A191V was the most prevalent (24/34; 70.6%). Notably, T21I mutation had a prevalence of 20.6% (7/34) and coexisted with either K90R (n = 3) polymorphism in Beta sequences with RAMs or P132H (n = 3) polymorphism for Omicron sequences with RAMs. Other NTV/r RAMs detected included P108S, with a prevalence of 5.88% (2/34), and L50F, with a prevalence of 2.94% (1/34). NTV/r RAMs were significantly higher (P < .001) in Delta (24/35) compared with Beta (4/34) and Omicron (6/34) sequences. CONCLUSIONS: The frequency of NTV/r RAMs in Botswana was low. Higher rates were observed in Delta VOCs compared to Omicron and Beta VOCs. As NTV/r use expands globally, continuous surveillance for drug-resistant variants is essential, given the RAMs identified in our study