ROME, Dec. 21 (Xinhua) -- The first case of new coronavirus strain was officially registered in Italy in a person recently returned from Britain, the Italian Health Ministry said on Monday.

In a statement, the ministry said the new variation of the virus first detected in the United Kingdom (UK) was sequenced at Celio military hospital in the Italian capital.

"The Scientific Department of Celio Military Polyclinic, cooperating with the National Health Institute (ISS) in this emergency, has sequenced the genome of the SARS-CoV-2 from a subject who tested positive for the virus variation found in Britain in recent weeks," it said.

The ministry said the patient and her partner, who had returned from the UK in the last few days with a flight landed at Fiumicino airport in Rome, were in isolation, along with their family members and close contacts.

The patient is a 25-year-old woman, and her British partner has tested positive for COVID-19, but not for the new virus strain so far, according to Ansa news agency quoting medical sources.

Both patients are asymptomatic, although the woman showed a high viral load, Ansa added.

On Monday, Italy's National Institute for Infectious Diseases Lazzaro Spallanzani said that "no alarming alteration of virulence has occurred so far, although attention must be kept high."

Spallanzani is a public research institute and Italy's reference hospital for infectious diseases. It was the first center in Europe to isolate the DNA sequence of the coronavirus in February.

"In our virology lab, the characterization of the positivity of travelers from England is underway," the institute's health management said.

"We have put the network of regional laboratories on alert in order to intercept any case that might be attributed to the (UK) variation."

The institute also explained that "viruses' mutations are in any case a circumstance that has already occurred during this pandemic, leading to an alternation of predominant strains in certain periods and in various territories."

With a decree by the health minister on Sunday, Italy declared a ban on flights between Italy and Britain between Dec. 21 and Jan. 6, thus joining other European countries in this step. The decision came soon after British leaders said they had detected a new and more transmissible strain of the coronavirus.

The health minister's decree also prohibited people who traveled in the UK in the last 14 days to enter Italy, also until Jan. 6.

According to the latest data from the Health Ministry on Sunday, Italy has so far registered 1,953,185 coronavirus cases. The total included 622,760 active infections, some 1,261,626 recoveries, and 68,799 fatalities.

Speaking to local media on Monday, ISS president Franco Locatelli said the virus variation should not affect the effectiveness of candidate vaccines.

As the world is struggling to contain the pandemic, countries including France, China, Russia, the United Kingdom and the United States are racing to find a vaccine.

According to the website of the World Health Organization, as of Dec. 16, there were 222 COVID-19 candidate vaccines being developed worldwide, and 56 of them were in clinical trials.