Boris Johnson outlines new restrictions after Omicron variant detected in UK. (Photo via BBC)

The United Kingdom has announced new measures in a bid to slow the spread of the newly identified Omicron coronavirus variant as two cases have been found in the country.

According to British health minister Sajid Javid, the two linked cases of Omicron were connected to travel to southern Africa.

Javid said the two cases were detected in Chelmsford and Nottingham, and both patients as well as their households are under quarantine.

Today I can announce one thing that we are doing immediately is carrying out targeted testing and sequencing of positive cases in the two areas that are affected, Javid said Saturday.

A top British health official said there was a reasonable chance that vaccines could be less effective against it.

There is a reasonable chance that at least there will be some degree of vaccine escape with this variant, said England’s Chief Medical Officer Chris Whitty.

The new variant - called B.1.1.529 - has a spike protein that is significantly different to the one in the original coronavirus on which Covid-19 vaccines are based, the UK Health Security Agency (HSA) said on Thursday.

Its mutations are likely to evade the immune response generated both by vaccination and prior infection. Also, it has mutations associated with increased infectivity.

As of Saturday morning, Botswana, Belgium, Hong Kong and Israel have had cases of the new variant.

If anyone has traveled to these four countries or any of the other red-listed countries in the last four days then they must self-isolate and take PCR tests, Javid said.

The UK said Thursday it would place six South African countries under red list travel restrictions due to concerns over the new variant. The countries include Botswana, Eswatini, Lesotho, Namibia, South Africa and Zimbabwe.

In addition, Malawi, Mozambique, Zambia and Angola will be added to the country’s travel red list from 0400 GMT on Sunday.

Meanwhile, Prime Minister Boris Johnson said Saturday passengers arriving from all countries would have to self-isolate until receiving a negative result from a PCR test.

Johnson also said that wearing face masks will be mandatory in shops and on public transport from next week.

We will require anyone who enters the UK to take a PCR test by the end of the second day after their arrival and to self-isolate until they have a negative result, he told a news conference.

We need to buy time for our scientists to understand exactly what we are dealing with, he added.