However, looking for antibodies in preserved blood samples, researchers at Akershus University Hospital (Ahus) found a positive result in December 2019 – the same month when the virus was first detected in China.
“This was very surprising. “We looked at blood samples until December to make sure we were going far enough in the past, but we did not expect to find a positive result so soon,” said project leader Anne Eskild.
Akershus University Hospital took blood samples from all pregnant women in the first trimester from December 2019 to December 2020. As part of Pregnancy Care in Norway, blood samples were taken from all pregnant women for syphilis testing. All samples are stored for monitoring of potential infectious diseases.
“There are probably few other countries that have access to stored blood samples at the population level, so there are few or no retrospective cases,” Eskild said.
The research team was given access to anonymous testing of samples under the Infection Control Act. About 500 samples a month were tested for covidine antibodies, and one positive case was detected in December 2019, two in January 2020 and one in February and March, experts said.
Out of a total of 6,020 women examined throughout the period, antibodies were detected in 98 women. “It must be borne in mind that some false positive results may occur, but scientists conclude that the findings show that the virus circulated in Norway as early as 2019,” the report said.
There are no systematic data on who women who had the infection and whether they had symptoms, but it can be seen that women who had antibodies before March 2020 were born in Norway, Eastern Europe, Africa or the Middle East.
“There is a lot of evidence that they were infected either in other parts of the world or through relatives who were outside Norway,” said Eskild, who said the findings suggested the infection may have spread around the world earlier than we thought.
The first confirmed cases in the world date back to December 2019, and were discovered in Wuhan, China.
“Our discovery changes the history of the coronavirus epidemic, both in Norway and around the world,” Eskild concludes.