As a precautionary measure to cope with the fear of spreading of Omicron,? the UK has re-introduced compulsory pre-departure tests for all travellers entering the country and added Nigeria to its travel ban red list.

According to the latest analysis conducted by the UK Health and Security Agency (UKHSA), the shorter window between infection and infectiousness for the Omicron variant increases the efficacy of pre-departure testing as it is more likely to identify positive cases before travel.

Therefore, starting Tuesday morning, anyone arriving in the UK is required to provide a pre-booked negative polymerase chain reaction (PCR) or lateral flow test – taken no earlier than 48 hours before departure. This applies to vaccinated passengers and children aged 12 and above.

"We knew this winter would be challenging but the arrival of a new variant means we must further strengthen our defences," said UK Health Secretary Sajid Javid.

"As our world-leading scientists continue to understand more about the Omicron variant we are taking decisive action to protect public health and the progress of our COVID-19 vaccination programme. I urge everyone to do their bit to slow the spread by following the new travel rules, wearing masks where mandatory and most importantly getting the booster jab when called," he said.

Under current rules, travellers only needed to self-isolate until they tested negative within two days of arriving into the country.

Scientists have raised concerns that the heavily-mutated Omicron variant, first identified in South Africa, may be more transmissible than the dominant Delta COVID strain and work remains ongoing to establish if it can escape immunity from the vaccines.

The Department of Health and Social Care (DHSC) said that in light of the emerging evidence and the changing global picture with regards to the spread of Omicron, airlines will be required to check for pre-departure tests alongside completed Passenger Locator Form, and passengers will not be allowed to board a flight without providing evidence of a negative test result.

Given the reduced incubation period of the Omicron variant, passengers are advised to take the pre-departure test as close as possible to their scheduled departure to the UK and no earlier than 48 hours before travelling, the DHSC said.

With the vast majority of cases in the UK having clear links to overseas travel from South Africa and Nigeria, from 4.00 am on Monday all UK and Irish citizens and residents arriving from Nigeria must isolate in a government-approved managed quarantine hotel facility for 10 days, and receive two negative PCR tests, as further precautionary action is taken against the Omicron variant.

The government said that over the past week, 21 Omicron cases reported in England originate from Nigeria, which has been added to the travel ban red list from Monday morning.

All these additional travel related measures will be reviewed after three weeks, on December 20.

“Following developments in the past week, the science shows that we must be cautious in guarding against this new variant and so while we appreciate this, (it) will be difficult for the travel sector, it's important we prioritise public health," said UK Transport Secretary Grant Shapps.

“As we learn more about the Omicron variant, we will review these temporary measures to ensure they continue to be proportionate and necessary to protect public health,” he said.

Anyone arriving from Nigeria before 4.00 am Monday, when the new rules kick in, will be advised and strongly encouraged to isolate at home, and their household should also self-isolate for 10 days starting with their arrival in England.

Affected individuals will be contacted and offered free PCR tests to be taken on the eighth day after arrival.

British and Irish citizens, or those with residence rights, arriving to England from countries on the red list - which includes South Africa, Botswana, Lesotho, Eswatini, Zimbabwe, Namibia, Malawi, Mozambique, Zambia, Angola and soon Nigeria – are required to book a managed quarantine hotel in advance.

The quarantine package will include a quarantine hotel, quarantine transport and a travel test package for COVID-19 tests on day 2 and day 8 of quarantine.

Analysis by the UKHSA suggests there is strong indication of Omicron presence in Nigeria, and several cases identified in the UK are linked to travel from Nigeria.

The country also has very strong travel links with South Africa, for example Nigeria is the second most popular flight destination from Johannesburg, the DHSC said.

The UKHSA said it continues to monitor the situation closely, in partnership with scientific and public health organisations across the world.?

(With PTI Inputs)