SARS-CoV-2 infection in general practice in Ireland: a seroprevalence study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody testing in community settings may help us better understand the immune response to this virus and, therefore, help guide public health efforts.

To conduct a seroprevalence study of immunoglobulin G (IgG) antibodies in Irish GP clinics.

Participants were 172 staff and 799 patients from 15 general practices in the Midwest region of Ireland.

This seroprevalence study utilised two manufacturers' point-of-care (POC) SARS-CoV-2 immunoglobulin M (IgM)-IgG combined antibody tests, which were offered to patients and staff in general practice from 15 June to 10 July 2020.

IgG seroprevalence was 12.6% in patients attending general practice and 11.1% in staff working in general practice, with administrative staff having the lowest seroprevalence at 2.5% and nursing staff having the highest at 17.6%. Previous symptoms suggestive of COVID-19 and history of a polymerase chain reaction (PCR) test were associated with higher seroprevalence. IgG antibodies were detected in approximately 80% of participants who had a previous PCR-confirmed infection. Average length of time between participants' positive PCR test and positive IgG antibody test was 83 days.

Patients and healthcare staff in general practice in Ireland had relatively high rates of IgG to SARS-CoV-2 compared with the national average between 15 June and 10 July 2020 (1.7%). Four-fifths of participants with a history of confirmed COVID-19 disease still had detectable antibodies an average of 12 weeks post-infection. While not proof of immunity, SARS-CoV-2 POC testing can be used to estimate IgG seroprevalence in general practice settings.