The severe acute respiratory syndrome coronavirus (SARS-CoV-2) B.1.1.7 variant, also known as the UK variant, is spreading globally. With observed heightened transmissibility, it and can spread faster than previous variants.
To date, the variant has reached many countries, with the United States reporting more than 3,000 cases.
Researchers at the Swiss Institute of Bioinformatics and other institutions estimate that the B.1.1.7 variant may be dominant in Switzerland by March.
In the study, published on the medRxiv* server, the researchers performed whole-genome sequencing of SARS-CoV-2 samples obtained from a large diagnostic laboratory every week for genomic surveillance.
The UK variant
In December 2020, the United Kingdom (UK) variant, also called B.1.1.7, was reported to the World Health Organization (WHO).
Multiple variants were also reported alongside the emergence of the B.1.1.7 variant. These include the South African variant (B.1.351) and the Brazilian variant (P.1).
The B.1.1.7 variant spreads faster and more efficiently across populations than previous strains. Though initial studies have shown that the variant causes only mild to moderate illness, new evidence has suggested that this variant might be associated with an increased risk of death.
Meanwhile, the B.1.351 variant may be more resistant to vaccines and some therapies against coronavirus disease 2019 (COVID-19). The P.1 variant, on the other hand, emerged in early January and has already reached other countries, such as the US and Japan.
The researchers performed whole-genome sequencing-based on Violler AG's samples, an extensive diagnostic lab processing SARS-CoV-2 samples from across Switzerland, to arrive at the study findings.
Each week, SARS-CoV-2 samples were randomly selected for sequencing among all positive test samples at the laboratory. For each sample, the researchers know the test's date and the canton in which the test was performed.
Further, the team also used data from Dr. Risch medical laboratories, which screen their samples for the 501Y mutation by a variant-specific polymerase chain reaction (PCR) test. They conducted analyses for the seven economic regions.
The team quantified the transmission fitness advantage of the UK variant for two datasets. The first data set allowed the researchers to get estimates for the seven Swiss economic regions.
The study findings showed that a logistic growth rate of around 0.09 to 0.10 per day for Switzerland. By March, the B.1.1.7 will be dominant in Switzerland, based on the Swiss data tracking 501Y mutations.
As of today, the majority of new infections may already be caused by the B.1.1.7 variant since cases are confirmed 8 to 11 days after infection.
The team also showed that in the first half of January, the absolute numbers of the UK variant increased, while the absolute numbers of all other cases declined.
Overall, the study demonstrated a consistent signal for a considerable transmission advantage of the UK variant in Switzerland. The estimates coincide with the rates from UK, Denmark, and Switzerland.
The B.1.1.7 transmission rates appear to have slowed down in February globally, which may be due to adherence and compliance to mitigation measures against COVID-19.
About 4.9 percent of all confirmed cases over the study period were characterized through whole-genome sequencing. The team plans to continue their sequencing efforts every week with all data to be submitted to GISAID.
The team aims to help and facilitate the global tacking of SARS-CoV-2 and to monitor the spread of new variants.
To date, the number of cases worldwide has reached 117.60 million, with over 2.61 million deaths. The United States reports 29 million cases and about 527,000 deaths.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.