In October 2020, a national study called the PRECISE study was launched to look at the prevalence of Covid-19 antibodies in healthcare workers (HCWs) in two hospitals – University Hospital Galway (UHG) and St James’s Hospital (SJH) Dublin.
All staff currently working in these two hospitals were invited to have a blood test to determine the presence of antibodies produced after Covid-19 infection. The study was repeated in April 2021 in the same hospitals to evaluate changes in the number of infections six months later and to assess the response to vaccination in the meantime.
In the repeat study in April, over 5,000 HCWs (56 per cent of staff) across the two facilities participated and all roles in the hospitals were represented. This includes nurses, doctors, healthcare assistants (HCAs), administration staff and general support staff.
In SJH, 21 per cent of staff had antibodies produced after Covid-19 infection (increased from 15 per cent in October 2020). In UHG 13 per cent of staff had antibodies produced after Covid-19 infection (increased from 4.1 per cent in October). The increase from October 2020 to April 2021 is a reflection of the magnitude of the third wave of the pandemic nationally and at both sites, according to the HSE.
In UHG prevalence was highest among HCAs (21 per cent), followed by doctors (17 per cent), general support staff (17 per cent), nurses (14 per cent), administration staff (7.7 per cent) and allied health professionals (6.7 per cent).
In SJH it was highest in HCAs (39 per cent), followed by nurses (26 per cent), general support staff (25 per cent), administration staff (16 per cent), doctors (15 per cent) and allied health professionals (15 per cent).
These figures reflect the type of work performed by healthcare workers, as well as other factors including participants’ age, sex and living arrangements.
Overall 19 per cent of all infections were asymptomatic and 26 per cent of infections were undiagnosed. These results emphasise the importance of ongoing adherence to public health and infection control guidance incorporating appropriate use of personal protective equipment (PPE) including face masks in all interactions with other staff, and with patients, to protect both the patient and the HCW from unknowingly passing on infection to others.
“To maximise the chances of diagnosing all Covid-19 infections in HCW, we need ongoing easy access to testing for HCW, even when symptoms are mild.”
The study also looked at antibodies produced after vaccination.
The majority of the participants had been fully vaccinated by the time of the study. Of those that were fully vaccinated, 100 per cent had antibodies (called anti-spike antibodies) as a response to vaccination.
According to the HSE: “We know from other studies that vaccination protects from severe infection. However, it is important to note that vaccinated staff can still get Covid-19 infection, and all local infection prevention and control guidelines still need to be followed while we continue to fully understand the immunity produced by Covid-19 virus vaccination.”
The study PRECISE 2 is available here: https://www.hpsc.ie/a-z/respiratory/coronavirus/novelcoronavirus/research/precise/PRECISE%202%20Report.pdf