Early indications show most Omicron coronavirus cases are "mild", the World Health Organisation has said.
The official believes there is no evidence to suggest the efficacy of vaccines reduces when battling against the new variant.
The organisation, quoted by Reuters, suggested "most" cases so far examined are not severe.
They cautiously added there is still a lot not yet known about the new strain.
It comes after Botswana's health ministry declared on Tuesday that nearly 80 per cent of cases of the Omicron variant detected in the country were asymptomatic.
WHO say more than 40 different mutations have already been identified.
But the official did say some mutations of the virus indicated an "increased risk" of quicker transmission.
Professor Neil Ferguson, giving evidence at the government's science and technology committee this morning, says it may be a while before we know how deadly Omicron could be.
He said it could be towards "the end of the month" before there is a clearer picture of the dangers the new variant possess.
He outlined: "What we have seen is Alpha has been more severe than the previous strain, a little, and Delta more severe again, so the trend we've seen is greater severity not less severity.
"Thankfully countered by better treatment by monoclonal antibodies, antivirals and all the other drugs, that mean people have a better chance of surviving severe COVID today than they did at the start of the pandemic."
On Tuesday night, the World Health Organisation released a statement saying all vulnerable people - including over-60s - should postpone travel plans following the emergence of the variant.
Others at risk of developing severe Covid symptoms should also shelve trips, they were advised.
"Persons who are unwell or at risk of developing severe Covid-19 disease and dying, including people 60 years of age or older or those with co-morbidities (e.g. heart disease, cancer and diabetes), should be advised to postpone travel," WHO said in a travel advice statement.
However, a complete travel ban will not prevent the global spread the variant, they added.
The statement went on: “Blanket travel bans will not prevent the international spread, and they place a heavy burden on lives and livelihoods.
"In addition, they can adversely impact global health efforts during a pandemic by disincentivizing countries to report and share epidemiological and sequencing data."
The WHO has also agreed to launch negotiations on an international treaty to prevent future pandemics.
