United Kingdom and Italy with more impact at the beginning of the pandemic in Portugal

The United Kingdom, with more cases, and Italy, with more weight in community transmission, were the countries with the greatest impact at the beginning of the covid-19 pandemic in Portugal, a study by the Ricardo Jorge Health Institute reveals today.

At least 277 people infected with SARS-CoV-2 from 36 countries entered Portugal by March 31, 2020, with the majority from the United Kingdom, Spain, France, Italy and Switzerland,

Another of the study’s conclusions is that, although the first cases of covid-19 notified in Portugal report on March 2, 2020, potential introductions will have occurred in late January, most of which occurred in the last week of February, in a “community transmission that was already running silently”.

The conclusions are part of “an extensive study of the genetic diversity of the new coronavirus” that INSA has been carrying out since the beginning of the pandemic, with the main objective of identifying the main introductions of the virus in the country, namely the countries that will have contributed more to this situation, said the agency Lusa Joana Isidro, of the Nucleus of Bioinformatics of the Department of Infectious Diseases.

“In March 2020, there was a huge effort, together with multiple laboratories and hospitals, to be able to collect samples and obtain the genetic information of the viruses that circulated in this initial phase of the pandemic and that made us one of the countries [the fifth in the world] ] who managed to collect more information on the genetic information of the new coronavirus “at this stage of the epidemic, said Joana Isidro.

Investigator Vítor Borges added that 1,275 virus samples collected in Portugal until the end of March were analyzed, representing 15.5% of confirmed cases in that period.

With these sequences it was possible to predict, based on the genetic uniqueness and with the travel history associated with the patients from which these samples were collected, that there were at least 277 independent introductions of the virus in Portugal until March 31 from “multiple countries”, such as the United Arab Emirates, Argentina, Brazil, Greece, the Netherlands, Andorra and Iceland.

According to the researchers, the country that has contributed with the largest number of introductions was the United Kingdom, followed by France, Spain and Italy.

“Each of these introductions had a different impact. There were introductions that had very limited transmission chains and caused few cases, while there were others that caused many cases”, underlined Vitor Borges.

Although Italy had far fewer introductions than, for example, the United Kingdom, it was the country that had the most weight in community broadcasting in Portugal.

It is estimated that a contagion that occurred in the Lombardy region around the 21st of February has caused about 4,000 cases of covid-19 in Portugal, spread over 44 municipalities in 11 districts, almost exclusively in the North and Center Region, where it is estimated which was responsible for about 20% and 60% of cases, respectively in these two regions, during the first phase of the epidemic.

Regarding the number of infections coming from each country and in which region of Portugal they will have been introduced, the study points out that the United Kingdom had a “great weight”, with many entries in Lisbon and Vale do Tejo and in the North.

“Spain had transversal introductions throughout the country,” said Vítor Borges, pointing out the “very curious” fact that many entries have taken place in the border regions.

This situation denotes that, in addition to introductions by air of infected patients who returned to the country or tourists, there were also many introductions in the border exchange between the two countries, he explained.

According to the researchers, many of the variants that had a major impact in the beginning of the pandemic, such as that of Italy, were not found in a large national sample that INSA carried out in November, which shows that the public health measures taken were able to mitigate this spread.