The overall global risk related to the new Omicron coronavirus variant is 'very high,' the World Health Organisation has said.

In a technical brief to its member States, the WHO detailed the potential risks of the variant and the priority measures that need to be taken for the same. "Given mutations that may confer immune escape potential and possibly transmissibility advantage, the likelihood of potential further spread of Omicron at the global level is high," WHO said in the brief.

"Depending on these characteristics, there could be future surges of Covid-19, which could have severe consequences, depending on a number of factors including where surges may take place. The overall global risk related to the new VOC Omicron is assessed as very high," it said.

The UN Health body said that there is "substantial uncertainty" regarding the transmissibility, immune escape potential (from either infection- or vaccine-induced immunity), clinical presentation, severity of disease, and response to other available countermeasures such as diagnostics and therapeutics when it comes to the new variant.

"Depending on these characteristics, if another major surge of Covid-19 takes place driven by Omicron, consequences may be severe. Increasing cases, regardless of a change in severity, may pose overwhelming demands on health care systems and may lead to increased morbidity and mortality," it said.

"The impact on vulnerable populations would be substantial, particularly in countries with low vaccination coverage. To date, no deaths linked to Omicron variant have been reported," it added.

At present, local transmission has been reported in South Africa and there is evidence of spread to several countries in four WHO regions (African, Eastern Mediterranean, European, and Western Pacific regions), including South Africa, Hong Kong, Botswana, UK, Italy, Belgium, Netherlands and Israel.

"Overall risk related to the new variant of concern Omicron is thus considered very high. The evidence for this assessment contains considerable uncertainty and will be updated as more information becomes available," WHO said.

Surveillance and sequencing efforts

Member States have been advised to increase surveillance and sequencing efforts and accelerate Covid-19 vaccination coverage as rapidly as possible, especially among populations designated as high priority who remain unvaccinated or are not yet fully vaccinated.

It further advised countries to use a "risk-based" approach to adjust international travel measures in a timely manner.

Multiple countries, including India have imposed more stringent travel restrictions for international arrivals owing to the spread of the new variant.

WHO further advised countries to ensure that preventative measures such as use of masks, physical distancing, ventilation of indoor space, crowd avoidance, and hand hygiene are adhered to. Contact tracing is also an important measure.

Countries must also ensure that early warning systems are in place to inform efficient adjustment of public health and social measures.

"In anticipation of increased Covid-19 caseloads and associated pressure on the health system, ensure mitigation plans are in place to maintain essential health services and necessary health care resources are in place to respond to potential surges," it said.

WHO last week designated the variant B.1.1.529 a variant of concern. It named the variant Omicron, on the advice of WHO’s Technical Advisory Group on Virus Evolution (TAG-VE).