Almost one fifth of Tallaght Hospital staff have Covid antibodies

CORONAVIRUS ANTIBODIES were found in almost 20% of staff at Tallaght Hospital, according to a new study.

Over a three month period from mid-July to mid-October the Laboratory Medicine Department in Tallaght University Hospital conducted a study to evaluate the prevalence of antibodies (‘seroprevalence’) to SARS-CoV-2 (the virus causing COVID-19) among healthcare workers in the hospital.

The Tallaght Antibody Study (TAB) has determine what proportion of staff have had COVID-19 at some point since the onset of the pandemic.

This is the first Irish study to date to report SARS-CoV-2 seroprevalence of healthcare workers.

Commenting on the results Dr. Anna Rose Prior, Consultant Microbiologist commented “These results demonstrate that a high proportion of COVID infection in healthcare workers goes undetected and supports the requirement for universal mask use for all patient interactions during the pandemic, both to protect staff but also to minimise the risk of staff unknowingly transmitting infection to patients.

“This study enables us to identify colleagues who do and don’t develop a measurable immune response to COVID-19.

“The study is a 12 month study meaning we will follow all participants who want to remain in the study for 12 months, measuring their antibody levels at multiple time points.

“This will give us two key pieces of information, the first is understanding how long a measurable level of antibodies to COVID-19 is present in participants and secondly, how many staff develop antibodies during the coming waves of infection.

“I would also like to acknowledge the incredible work of the team in Laboratory Medicine who have dedicated their valuable spare time to conduct the study at what is a particularly busy time in the Hospital.”

Almost 1,200 volunteered to participate in the study which was open to staff from all departments and directorates (see footnote).

This study represents approximately one third of staff working in the Hospital, there was representation from all departments throughout the Hospital. All data and results are anonymised.

Antibodies to SARS-CoV-2 were detected in 18% of participants overall.

For staff with roles involving more direct patient contact the rate was 20% and for those with less direct patient the rate was 13%.

Before this study, 12% of participants had been diagnosed with COVID-19 at some point, based on a positive swab result.

When the group who had known previous infection was excluded, the seroprevalence among those never confirmed to have infection was 7.5%.

However over half of this group suspected they had infection at some point.

The initial results of this study indicate that nearly one fifth of Tallaght Hospital staff have antibody evidence of SARS-CoV-2 infection, acquired at some point since the onset of the pandemic.

This is higher than the rate of previously known infection in their participants.

The seroprevalence among our population of healthcare workers is significantly higher than the overall estimated national seroprevalence of 1.7% (as per SCOPI study, conducted by HPSC).

It is also significantly higher than that reported by seroprevalence studies from similar healthcare institutions in other countries that implemented similar community restrictions.