Italian scientists reported that they found antibodies to the SARS-CoV-2 coronavirus in blood samples isolated from asymptomatic patients back in September 2019, six months before the large-scale spread of the pathogen. According to the researchers, the unexpected results indicate that the pandemic could have started much earlier than WHO experts believe. Scientific work published in SAGE journals.
Scientists have identified antibodies to the pandemic coronavirus in 111 out of 959 people who underwent lung cancer screening between September 2019 and March 2020. 14 percent of cases were detected in September 2019 and over 30 percent in the second week of February 2020. At the same time, more than 50 percent of patients with antibodies to the receptor-binding domain (RBD) of the S-protein of the coronavirus were found in Lombardy, a region in northern Italy.
The results show an odd circulation of the virus among asymptomatic individuals in Italy months before the first patient was identified in the country, experts say.
At the same time, the detection of antibodies to coronavirus in those who did not have COVID-19 is not an exceptional case. For example, it is known that antibodies to SARS-CoV-2 can appear in those infected with a related virus that causes the common cold. There is also evidence that antibodies that neutralize SARS-CoV-2 are also present in the body of SARS patients in 2003. However, specific antibodies that target RBD have not yet been detected in patients who have not been exposed to pandemic coronavirus.
To confirm the conclusions of Italian scientists, it is necessary to conduct additional studies and prove that antibodies to RBD S-protein cannot arise as a result of the development of cross-immunity under the influence of related viruses, and also to exclude the possibility of contamination of samples.