Publish: 01 Jan 2021, 02:06 pm
The World Health Organization (WHO) has released a report setting out the risk assessment and guidance for a number of recently observed SARS-CoV-2 variants.
The Global Health Institution has highlighted a quartet of variants that are currently in circulation in its press release issued on Thursday.
The SARS-CoV-2 variant with a D614G substitution in the spike protein encoding gene is currently the most dominant form of the global virus, reports media.
It was initially observed in late January or February 2020 before overwhelming the strain identified in China.
It became the dominant strain in June, having increased infectivity and transmission to previous strains. It does not, however, cause greater illness or worsen the effectiveness of existing laboratory diagnoses, therapies, vaccines or epidemiological efforts.
The Danish "Cluster 5" Variant
This SARS-CoV-2 variant was identified in North Jutland, Denmark, in August and September.
It was characterized by its link to infection among the cultivated mink before it was subsequently transmitted to humans. It has multiple mutations that have not been observed previously.
Experts have raised concerned that this could result in reduced virus neutralization, which would reduce the extent and duration of immune protection from infection or vaccination.
The "Cluster 5" variant is currently being assessed for virus neutralization among humans infected with it, though Denmark has reported only 12 human cases in September, without indication of widespread transmission.
The Variant in the UK
Three weeks ago, the United Kingdom initially reported to WHO SARS-CoV-2 variant B117, which has since been shown to have 23 nucleotide substitutions without a phylogenetic relationship to the virus circulating in the country at the time.
The variant appeared initially in Southeast England, but has since replaced the virus lineages in the area as well as in London.
A preliminary assessment indicates the variant has increased transmissibility, but no change in disease severity—as per hospitalization length and 28-day case fatality—nor reinfection risk.
Another of this variant's mutations appears to have affected diagnostic PCR assays with an S gene target, however, the impact is not anticipated to be significant.
As of this week, the variant has been reported in 31 other countries, territories, areas in 5 of the 6 WHO regions.
The South Africa 5O1Y.V2 Variant
A new variant was detected by South African authorities on December 18, spreading rapidly among 3 provinces with an N501Y mutation.
A month earlier, routine sequencing observed this variant had largely replaced other SARS-CoV-2 viruses in regions of Eastern Cape, Western Cape, and KwaZulu-Natal provinces. Despite this rapid displacement and an observed higher viral load that could indicate transmissibility, further research is needed.
Additionally, WHO indicated there is currently no evidence of this variant being associated with more severe disease or worse outcomes, though again, more research is needed. As of this week, is has been reported in 4 other countries.
Response to Variants
Aside from affected nation's authorities currently undergoing epidemiological and virologic assessments on these variants, as well as the addition of the UK and South Africa variants' genomic data to the Global Initiative on Sharing Avian Influenza Data (GISAID), WHO highlighted a series of actions initiated to respond to the new threats.
Intensified sampling in affected regions would have to be carried out to interpret new variant circulation and spread.
National scientific teams would have to observe the mutations' effects on reinfection, vaccination, diagnostic testing, infection severity, and transmissibility.
WHO said government and research authorities would have to collaborate to analyze epidemiologic, modelling, phylogenetic and laboratory findings as they become available.
WHO and national authorities would have to work together to identify means of strengthening SARS-CoV-2 surveillance systems, as well as implementing or bolstering genetic sequencing capacity to evaluate variants.
Community engagement needs to be improved and communication to describe the public health implications of SARS-CoV-2 variants to the public, with emphasis on continued social distancing strategies while research continues.
Variant Risk Assessment
WHO stressed the commonality of viruses to change over time, often without direct benefit to its infectiousness or transmissibility, and sometimes limiting propagation. They also noted that virus mutation risk increases with the frequency of human and animal infections.
Although the initial assessment involves that the UK and South African variants do not cause a change in clinical presentation or severity, their higher case incidence potential could lead to increased COVID-19-related hospitalizations and therefore to death. As such, the WHO warned that more intensive public health response may be needed to control the transmission of variants, pending research.
Existing strategies of disease control—including epidemiological surveillance, strategic testing, contact tracing, and adjusted public health and social measures—are advised to continue during the investigation of the variants.
WHO also advised countries to increase routine systematic sequencing of SARS-CoV-2 viruses, where possible, to better monitor the development of variants.
The Authority has advised national and regional health organizations to work with the travel, transport and tourism sectors to ensure that travelers to and from countries affected by new variants are informed of variations and are resourced to prevent spread.
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