Detection of a SARS-CoV-2 variant of concern in South Africa.

Continued uncontrolled transmission of SARS-CoV-2 in many parts of the world is creating conditions for substantial evolutionary changes to the virus1,2. Here we describe a newly arisen lineage of SARS-CoV-2 (designated 501Y.V2; also known as B.1.351 or 20H) that is defined by eight mutations in the spike protein, including three substitutions (K417N, E484K and N501Y) at residues in its receptor-binding domain that may have functional importance3-5. This lineage was identified in South Africa after the first wave of the epidemic in a severely affected metropolitan area (Nelson Mandela Bay) that is located on the coast of the Eastern Cape province. This lineage spread rapidly, and became dominant in Eastern Cape, Western Cape and KwaZulu-Natal provinces within weeks. Although the full import of the mutations is yet to be determined, the genomic data-which show rapid expansion and displacement of other lineages in several regions-suggest that this lineage is associated with a selection advantage that most plausibly results from increased transmissibility or immune escape6-8.

Sixteen novel lineages of SARS-CoV-2 in South Africa.

The first severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in South Africa was identified on 5 March 2020, and by 26 March the country was in full lockdown (Oxford stringency index of 90)1. Despite the early response, by November 2020, over 785,000 people in South Africa were infected, which accounted for approximately 50% of all known African infections2. In this study, we analyzed 1,365 near whole genomes and report the identification of 16 new lineages of SARS-CoV-2 isolated between 6 March and 26 August 2020. Most of these lineages have unique mutations that have not been identified elsewhere. We also show that three lineages (B.1.1.54, B.1.1.56 and C.1) spread widely in South Africa during the first wave, comprising ~42% of all infections in the country at the time. The newly identified C lineage of SARS-CoV-2, C.1, which has 16 nucleotide mutations as compared with the original Wuhan sequence, including one amino acid change on the spike protein, D614G (ref. 3), was the most geographically widespread lineage in South Africa by the end of August 2020. An early South African-specific lineage, B.1.106, which was identified in April 2020 (ref. 4), became extinct after nosocomial outbreaks were controlled in KwaZulu-Natal Province. Our findings show that genomic surveillance can be implemented on a large scale in Africa to identify new lineages and inform measures to control the spread of SARS-CoV-2. Such genomic surveillance presented in this study has been shown to be crucial in the identification of the 501Y.V2 variant in South Africa in December 2020 (ref. 5).

Evaluation of the Alinity m HIV-1 assay for the quantification of HIV-1 RNA plasma viral load in a high-throughput molecular laboratory in South Africa.

BACKGROUND: Regular HIV-1 viral load monitoring forms an essential part of any successful HIV-1 treatment programme. Abbott Molecular recently released the Alinity m HIV-1 assay to be run on the Alinity m System, a fully automated, continuous and random access analyser using ReadiFlex™ technology. OBJECTIVES: Our study investigated the performance of the Alinity m HIV-1 assay in comparison to the cobas® HIV-1 test in a high-throughput molecular laboratory. STUDY DESIGN: We compared the performance of the Alinity m HIV-1 assay with the cobas® HIV-1 test, performed on both the cobas® 4800 and cobas® 6800 systems at three clinically relevant thresholds (50, 200 and 1000 cp/mL). RESULTS: Excellent correlation (r = 0.98) and agreement (mean bias -0.004 Log10 cp/mL) was achieved between the cobas® 4800 and Alinity m HIV-1 assay. While there was good correlation between the Alinity m HIV-1 assay and the cobas® 6800 (r = 0.99), Bland-Altman analysis indicated that the cobas® 6800 on average measured 0.22 Log10 cp/mL higher than the Alinity m HIV-1 assay across the dynamic range. Percentage agreement was excellent at the 200 cp/mL and 1000 cp/mL thresholds and was slightly lower at 50 cp/mL in comparison with the cobas® systems. CONCLUSIONS: The Alinity m HIV-1 assay compared well with the cobas® HIV-1 test on both the cobas® 4800 and cobas® 6800 systems in a high-throughput molecular laboratory in South Africa, a low- to middle-income country.

Improved detection of JC virus in AIDS patients with progressive multifocal leukoencephalopathy by T-antigen specific fluorescence resonance energy transfer hybridization probe real-time PCR: evidence of diverse JC virus genotypes associated with progressive multifocal leukoencephalopathy in Southern Africa.

JC virus (JCV) causes progressive multifocal leukoencephalopathy under conditions of immunosuppression, especially associated with HIV. Despite the high prevalence of HIV-1 infection, few cases of progressive multifocal leukoencephalopathy have been reported and only a small number of JCV strains have been characterized in AIDS patients in Southern Africa. Diagnosis of progressive multifocal leukoencephalopathy through PCR detection of JCV DNA in CSF may result in false negative results if variable regions of the genome are targeted. Characterization of circulating JCV genotypes in Southern Africa may assist with designing appropriate diagnostic assays and characterizing the molecular epidemiology of JCV in African AIDS patients. In this study, a new real-time PCR using fluorescence resonance energy transfer hybridization probes targeting the conserved large T-antigen was developed and compared to a conventional nested PCR targeting the variable VP1 region. Validation against known JCV positive specimens confirmed its specificity while amplification of a serial dilution of JCV control DNA suggests that the new real-time PCR can detect lower concentrations of JCV than the VP1 nested PCR. Investigation of CSF specimens from 44 suspected progressive multifocal leukoencephalopathy patients suggest that the new assay is more sensitive being able to detect JCV in 12 specimens versus 5 specimens with the VP1 nested PCR. Sequence analysis confirmed that the T-antigen region is completely conserved while phylogenetic analysis of the five VP1 products identified two genotype 3, one genotype 1 and two genotype 4 strains, the latter two identified for the first time in South African AIDS patients.

Replacement of neuraminidase inhibitor-susceptible influenza A(H1N1) with resistant phenotype in 2008 and circulation of susceptible influenza A and B viruses during 2009-2013, South Africa.

BACKGROUND: Data on the susceptibility of influenza viruses from South Africa to neuraminidase inhibitors (NAIs) are scarce, and no extensive analysis was done. OBJECTIVES: We aimed to determine oseltamivir and zanamivir susceptibility of influenza A and B virus neuraminidases (NAs), 2007-2013, South Africa. PATIENTS/METHODS: We enrolled participants through national influenza-like illness surveillance, 2007-2013. Influenza diagnosis was by virus isolation and quantitative polymerase chain reaction (qPCR). Drug susceptibility was determined by chemiluminescence-based NA-STAR/NA-XTD assay. Sanger sequencing was used to determine molecular markers of NAI resistance. RESULTS: Forty percent (6341/15 985) of participants were positive for influenza viruses using virus isolation (2007-2009) and qPCR (2009-2013) methods. A total of 1236/6341 (19.5%) virus isolates were generated of which 307/1236 (25%) were tested for drug susceptibility. During 2007-2008, the median 50% inhibitory concentration (IC50 ) of oseltamivir for seasonal influenza A(H1N1) increased from of 0.08 nmol/L (range 0.01-3.60) in 2007 to 73 nmol/L (range 1.56-305 nmol/L) in 2008. Influenza A isolates from 2009 to 2013 were susceptible to oseltamivir [A(H3N2) median IC50  = 0.05 nmol/L (range 0.01-0.08); A(H1N1)pdm09 = 0.11 nmol/L (range 0.01-0.78)] and zanamivir [A(H3N2) median IC50  = 0.56 nmol/L (range 0.47-0.66); A(H1N1)pdm09 = 0.35 nmol/L (range 0.27-0.533)]. Influenza B viruses were susceptible to both NAIs. NAI resistance-associated substitutions H275Y, E119V, and R150K (N1 numbering) were not detected in influenza A viruses that circulated in 2009-2013. CONCLUSIONS: We confirm replacement of NAI susceptible by resistant phenotype influenza A(H1N1) in 2008. Influenza A and B viruses (2009-2013) remained susceptible to NAIs; therefore, these drugs are useful for treating influenza-infected patients.