Researchers at Akershus University Hospital (Ahus) have found antibodies against COVID-19 dating back to December 2019, a month before the first case was detected in Europe.
The first case in Europe was detected on 27 January 2020. Officially, the virus didn't spread to Norway until 24 February of the same year. Ahus’s discovery thus stems from the same period as the first proven case was found in China.
The researchers themselves described the discovery as “very surprising”.
“The discovery changes the story of the corona epidemic”, Ahus project manager Anne Eskild said in a statement.
The researchers searched for antibodies in anonymously stored blood samples, in accordance with the Infection Control Act. The samples were taken from pregnant women in the first trimester and as part of maternity care and stored to monitor potential infectious diseases.
Antibodies were detected in 98 of the 6,520 samples analysed. Even if a certain proportion of false-positive results must certainly be taken into account, the conclusions hold water, the researchers say. Furthermore, there are many indications that they were infected abroad, Esklid noted.
“Our findings change the history of the corona pandemic both in Norway and in the world,” Eskild pointed out.
According to the Ahus researchers, this indicates that the infection was widespread in large parts of the world earlier than we have thought so far.
“There are probably few other countries that have access to stored blood samples at a population level, and therefore there are few or no other retrospective studies,” Eskild concluded.
According to an Italian study from Milan, the coronavirus was present in Italy in 2019, too, as early as September.
Earlier, researchers at University of California San Diego School of Medicine, with colleagues at the University of Arizona and Illumina, estimated, using molecular dating tools and epidemiological simulations, that the SARS-CoV-2 virus was likely circulating undetected for at most two months before the first human cases of COVID-19 were described in Wuhan, China in late-December 2019.