HSE announces results of seroprevalence study

Thursday 20th August

HSE seroprevalence study estimates 1.7% national prevalence of COVID-19 

Thursday, 20th August, the HSE published results of the Study to Investigate COVID-19 Infection in People Living in Ireland (SCOPI): A national seroprevalence study, June-July 2020. This study, the first of its type in Ireland, measured antibodies to SARS-CoV-2 virus, which are an indication of past infection with COVID-19. The study reports a prevalence of infection of 0.6% in Sligo and 3.1% in Dublin. Based on these results, HPSC estimates a national prevalence rate of 1.7%.

A representative sample of 1,733 people aged 12 to 69 years in Sligo and Dublin participated in the study carried out by the Health Protection Surveillance Centre (HPSC) and the National Virus Reference Laboratory (NVRL) study in June/July this year. Of the 1,733 samples tested, 33 tested positive for antibodies. Twenty-eight of these were in Dublin, and five in Sligo. No statistical differences were identified in the prevalence by age group, or between males and females.

Of those who were found to have antibodies, 73% had symptoms that are included in the Irish COVID-19 case definition; that is, one or more of the following: fever, cough, shortness of breath, loss of sense of taste or loss of sense of smell. One third of all those who were found to have antibodies reported loss of sense of smell and/or taste. 

Dr Derval Igoe, Principal Investigator for SCOPI at the HPSC said: “It is not surprising that a relatively low national seroprevalence of 1.7% was observed here. Other countries in Europe, such as Spain and Italy, where there has been a much more intense epidemic, have reported national seroprevalence estimates of 5% and 2.5% respectively. This means that the vast majority of people living in Ireland had not been infected with SARS-CoV-2 virus by the time of the study. As a society, we need to continue with our public health measures, including physical distancing, respiratory etiquette, hand hygiene and the use of face coverings, until a vaccine for COVID-19 is available.” 

Using the prevalence data from this study, the HPSC estimates that that 59,500 people in Ireland in the age group 12 to 69 years had been infected with SARS-CoV-2 up to mid-July; three times more than that detected via surveillance of notified cases.

Dr Ronan Glynn, Acting Chief Medical Officer added: “The low prevalence rate indicates that the measures put in place early, as well as the sensitive case surveillance, testing and contract tracing system, have been effective in minimising community transmission.”

Dr John Cuddihy, Director of the HPSC, added: “According to the World Health Organization (WHO), 80% of all COVID-19 infections are mild or asymptomatic, so some of these cases are unlikely to be detected. Furthermore, not all symptomatic people will seek health care or have a COVID-19 diagnostic PCR test. Therefore, underestimation of cases of COVID-19 highlights the importance of seroprevalence studies as a complement to case-based surveillance. We will be repeating studies on the prevalence of COVID-19 infection over the next year to help us understand how COVID-19 is spreading within the community in Ireland.”

The study team sincerely thanks all those members of the public who took the time to participate in this study, without whom, this new knowledge would not be possible.



Note to Editors

The full report of the results is available at www.hse.ie/scopi

This study received approval from the National COVID-19 Research Ethics Committee and was coordinated by the HSE Health Protection Surveillance Centre (HPSC), and the National Virus Reference Laboratory (NVRL), in collaboration with The Central Statistics Office and the Department of Health.

The study design is based on a protocol developed by the World Health Organization.

Those invited to participate in this study were selected randomly from the HSE Primary Care Reimbursement Service (PCRS) database in two counties: Dublin and Sligo. Result letters were posted on 4 August 2020 to all participants who indicated they wanted their results and the GPs of those participants who opted to inform their GP of the result.

HSE PCRS has a publicly available privacy statement which explains how it collects and uses personal information for the provision of services administered by HSE PCRS. It explains how PCRS complies with data protection legislation, who receives personal data from PCRS and how PCRS deals with individuals’ rights in relation to their personal data.  The statement explains that PCRS can share data within HSE for protecting wider public health interests.

The presence of COVID-19 antibodies in a blood sample is a sign that a participant was infected with the COVID-19 virus at some time in the past. Currently, there is not enough evidence to be sure if antibodies to COVID-19 will protect people from getting sick with COVID-19 again. Further evidence is required to understand how long the antibodies last and what level of antibodies is necessary to confer immunity. This is why it is very important that everyone continues to follow all the social distancing and hygiene measures recommended by the government regardless of their antibody test result. 

Last updated on: 20 / 08 / 2020