For the first time, a study was conducted in Ukraine to coordinate the number of people with antibodies to the coronavirus SARS-CoV-2, the causative agent of COVID-19. Thus, according to preliminary results, at least 40% of Ukrainians have antibodies to SARS-CoV-2.
Preliminary results of the study
As of June-July 2021, 40.5% of study participants detected detectable IgG antibodies to one of the proteins of the coronavirus SARS-CoV-2 (RBD domain of S1 protein).
According to a preliminary statistical estimate, if this indicator is extrapolated to the entire population of Ukraine, it is likely to be in the range from 39.3% to 41.7% (95% confidence interval).
This value should be considered as the minimum proportion of Ukrainians who have been infected with SARS-CoV-2 since the beginning of the pandemic. The actual number is probably larger , because the results of the study are influenced by the following factors:
- some people at certain periods after infection do not have antibodies to the RBD domain of S1 protein, but have antibodies to other proteins – this will be further assessed in the study;
- due to the possible short-term circulation of antibodies in some people who underwent COVID-19, they may have disappeared by the time of the study;
- antibody levels could be too low for detection by laboratory methods or be below the threshold of a particular test system.
All these aspects will be taken into account during the in-depth analysis of the research results. The research team plans to prepare a full report in September 2021.
Note that the presence of antibodies to the coronavirus that causes COVID-19 indicates that a person has previously been in contact with the virus, but is not a sign of the disease. Detection of antibodies does not guarantee immunity to all strains of SARS-CoV-2 virus and is not a reason to refuse vaccination. It is unknown at this time what the level of antibodies to protect should be and how long they last.
How the data was collected
Data collection for the study lasted from June 7 to July 9, 2021. For 5 weeks, 54 mobile teams worked in all regions of Ukraine , conducting blood sampling and interviewing Ukrainians about their experience with COVID-19, behavior during a pandemic, compliance with quarantine standards, socio-demographic factors that may affect the infection, etc.
A total of 154 interviewers, 168 health workers, 87 workers and Red Cross volunteers joined the data collection . 129 health care facilities were involved in the centrifugation and storage of blood samples .
The study interviewed and collected suitable blood samples from 6,398 healthy adults randomly selected. One third of the study participants live in rural areas, one third – in regional centers, another third – in other cities and towns.