Antibody analysis of patient serums can be used to study prevalence of coronavirus in the population
Keywords:The sample materials and antibody methods of the HUS Diagnostic Center can be utilised in patient diagnostics, as well as more extensive epidemiological studies at the population level.
Osastonylilääkäri Satu Kurkela, osastonylilääkäri Hanna Jarva ja erikoistuva lääkäri Maarit Ahava valmistautumassa satunnaisotantaan laboratorion seeruminäytteistä tutkimusta varten. Kuva: Mikko Hinkkanen, HUS
A study conducted at the Virology and Immunology Laboratory of the HUS Diagnostic Center showed that when the Omicron variant emerged last winter, it spread fast especially among those under the age of 30.
Surplus blood samples from HIV tests in the HUS area were used as material in the study. Researchers picked 100 blood samples at random once a week. The samples were examined for two coronavirus antibodies - the N and S antibodies. The N antibodies indicate that the person had contracted the coronavirus, and the S antibodies indicate that the person had been infected by the coronavirus earlier or has been vaccinated.
The study examines a time of 16 weeks between 15 November 2021 and 6 March 2022. The Omicron variant was first detected in Finland on 29 November 2021.
In the first five weeks (46–50/2021) N antibodies suggesting a recent coronavirus infection were found in 5.2 percent of the samples. In the last five weeks (5–9/2022) they were found in 28.2 percent of the samples. This means that a sharp rise occurred in 16 weeks. The increase was especially steep among those under the age of 30.
“It is possible that the observation was related to the greater number of social contacts that people in this age group had during the research period compared with other age groups”, says Chief Physician Satu Kurkela.
Nearly 300,000 infected
Based on the material, initial conclusions can be drawn about how many people in the HUS area were infected by coronavirus in the period under investigation.
“The number is at least 300,000, but according to the estimate it is significantly higher”, Kurkela says.
A case of coronavirus infection confirmed by laboratory testing was detected in 230,000 people. About 1.5 million people live in the HUS area.
“At the HUS Diagnostic Center we have expertise and sample materials available that can be utilised both in patient diagnostics and in extensive epidemiological studies that produce information to support decision-making on national strategies, for example for restrictions”, Kurkela says.
The study was published in the European Journal of Clinical Microbiology and Infectious diseases.