INTRODUCTIONHuman immunodeficiency virus type 1 (HIV-1) genotyping resistance test (GRT) is essential for monitoring HIV-1 drug resistance mutations (DRMs). High cost and HIV-1 genetic variability are challenges to assay availability in Singapore. An in-house Sanger sequencing-based GRT method was developed at the Communicable Disease Centre (CDC), Singapore's HIV national treatment reference centre for both subtype B and non-subtype B HIV-1.

MATERIALS AND METHODSThe in-house GRT sequenced the fi rst 99 codons of protease (PR) and 244 codons of reverse transcriptase (RT) in the pol gene. The results were compared with the Food and Drug Administration (FDA)-approved ViroSeq™ HIV-1 Genotyping System.

RESULTSSubtype assignment for the 46 samples were as follows: 31 (67.4%) CRF01_AE, 14 (30.5%) subtype B and 1 (2.1%) subtype C. All 46 samples had viral load of ≥500 copies/mL, and were successfully amplified by the in-house primer sets. Compared to the ViroSeq™ test, our in-house assay showed drug-resistance conferring codon concordance of 99.9% at PR and 98.9% at RT, and partial concordance of 0.1% at PR and 1.1% at RT. No discordant result was observed.

CONCLUSIONThe assay successfully identified DRMs in both subtype AE and B, making it suitable for the efficient treatment monitoring in genetically diverse population. At less than half of the running cost compared to the ViroSeq™ assay, the broadly sensitive in-house assay could serve as a useful addition to the currently limited HIV genotyping assay options for resource-limited settings, thereby enhancing the DRM surveillance and monitoring in the region.

Anti-Retroviral Agents ; pharmacology ; Drug Resistance, Viral ; genetics ; Genes, pol ; genetics ; Genotyping Techniques ; methods ; HIV Infections ; drug therapy ; virology ; HIV-1 ; drug effects ; genetics ; Humans ; Mutation ; Sequence Analysis, DNA ; methods ; Singapore

INTRODUCTION: Inappropriate attendances (IAs) to emergency departments (ED) create an unnecessary strain on healthcare systems. With decreased ED attendance during the COVID-19 pandemic, this study postulates that there are less IAs compared to before the pandemic and identifies factors associated with IAs. METHODS: We performed a retrospective review of 29,267 patient presentations to a healthcare cluster in Singapore from 7 April 2020 to 1 June 2020, and 36,370 patients within a corresponding period in 2019. This time frame coincided with local COVID-19 lockdown measures. IAs were defined as patient presentations with no investigations required, with patients eventually discharged from the ED. IAs in the 2020 period during the pandemic were compared with 2019. Multivariable logistic regression was performed to identify factors associated with IAs. RESULTS: There was a decrease in daily IAs in 2020 compared to 2019 (9.91±3.06 versus 24.96±5.92, P<0.001). IAs were more likely with self-referrals (adjusted odds ratio [aOR] 1.58, 95% confidence interval [CI] 1.50-1.66) and walk-ins (aOR 4.96, 95% CI 4.59-5.36), and those diagnosed with non-specific headache (aOR 2.08, 95% CI 1.85-2.34), or non-specific low back pain (aOR 1.28, 95% CI 1.15-1.42). IAs were less likely in 2020 compared to 2019 (aOR 0.67, 95% CI 0.65-0.71) and older patients (aOR 0.79 each 10 years, 95% CI 0.78-0.80). CONCLUSION ED IAs decreased during COVID-19. The pandemic has provided a unique opportunity to examine factors associated with IAs.
COVID-19 ; Communicable Disease Control ; Emergency Service, Hospital ; Humans ; Pandemics ; Retrospective Studies ; SARS-CoV-2