The HSE is urging people who have already been invited to take part in a major new COVID-19 study, to participate.

The HSE recently invited over 5,000 people to participate in The Study to Investigate COVID-19 Infection in People Living in Ireland (SCOPI). It aims to provide an overall estimate of how many people here have been infected with the virus.

Participants were invited from Dublin and Sligo because they represent parts of the country with higher and lower known levels of infection.

In the two weeks since the study was launched, the HSE has had a positive response, with over 2,000 people responding to the initial invitation, and over 1,600 people participating.

The HSE is now issuing reminder letters to people who have been invited to participate, but have not yet responded.

"This study is really important to help us understand the true level of infection in the population. To date, we have had good take up of our invitation, and we would like to thank all those who have already taken part. They are making a significant contribution to our knowledge of this virus," commented Dr Lorraine Doherty, the HSE's national clinical director for health protection.

Those who have been invited to take part have until Wednesday, July 8, to agree to participate.

Participants are asked to complete a short questionnaire with HSE staff via telephone and to provide a blood sample to test for antibodies. The sample is taken by a phlebotomist in a local centre arranged by the HSE.

Serological (blood) tests measure the antibody response in an individual. Antibodies to SARS-CoV-2, the virus that causes COVID-19, are produced over several weeks after infection with the virus. The presence of antibodies indicates that a person was infected with the virus, irrespective of whether the individual had severe or mild disease, or even infection without any symptoms (asymptomatic).

"As the country begins to reopen, we must remember that COVID-19 has not gone away. We are constantly learning new things about this virus and all of this information is helping us in our response.

"This study could help us better understand how long antibodies last and what protection they may provide against new infection of COVID-19. It can also help us estimate the level or prevalence of infection of COVID-19 in the population across different age groups and this can inform how we manage the virus into the future," explained Dr Cillian de Gascun, director of the National Virus Reference Laboratory.

Participants will be provided with their individual results and those who are found to have antibodies for COVID-19 will be asked to take part in a follow-up study. This will involve three further blood tests and questions about COVID-19 symptoms over a 12-month period.

The HSE said that this will help our understanding of how long antibodies last, and if they have a role in preventing repeat infections.

"By participating in the study, people are playing a really important part in the national effort against COVID-19," Dr de Gascun said.

Initial results are expected in late August.