One in five staff in the State’s largest hospital have been infected with Covid-19, a new study indicates.
Antibodies for the virus were detected in 21 per cent of healthcare workers at St James’s Hospital in Dublin, and 13 per cent of staff at University Hospital Galway, the study found.
Staff were tested last April, in the second round of the Precise study conducted by a research team from the two hospitals.
In the first round, in October 2020, 15 per cent of healthcare workers in St James were seroprevalent (having antibodies for the virus), and 4.1 per cent in UHG.
The rise in infection over the six-month interval reflects the increase in incidence of Covid-19 in the community and, specifically, in healthcare workers during the third wave of the pandemic.
Specific groups had a higher incidence of infection: healthcare assistants, staff of African/black identity, those with a lower level of education and daily contact with patients, nurses, 18 to 29-year-olds, men and staff living with other healthcare workers.
At St James’s Hospital, prevalence was 72 per cent among staff of Nigerian background, 42 per cent among staff of African background and 39 per cent among healthcare assistants.
More than 5,000 staff were tested at the two locations and response rate was 56 per cent.
Asymptomatic
One-quarter of infections (26 per cent) had been previously undiagnosed and half of these were asymptomatic. “Although the majority of these infections were associated with only mild symptoms, it is still possible that these undiagnosed healthcare workers were working during the infectious period, with potential for onwards transmission to patients and other staff members if proper use of PPE and other infection prevention and control measures were not strictly adhered to.”
At the time of testing in April, 95 per cent of staff had started vaccination and 81 per cent were fully vaccinated.
A full 100 per cent of those fully vaccinated, and 99 per cent of those partially vaccinated, had serological evidence of vaccine response.
In relation to the difference in seroprevalence between the two hospitals, the authors say this is related to local community incidence, to social and demographic factors, and to local work practices.
“The difference in seroprevalence between the two sites primarily reflects the difference in community incidence, with a corresponding higher seroprevalence seen in the staff at SJH, in the more densely populated capital city of Dublin, which has had higher community incidence throughout the pandemic thus far.”
Some 23 out of 4,111 (0.6 per cent) of those fully vaccinated had a breakthrough infection at a median of 30 days after their second dose. All had been administered the Pfizer vaccine, the most commonly received vaccine.
Among participants who took part in both phases of the research and who were antibody positive, showing past infection, 90 per cent remained antibody positive six months on.
The researchers have recommended the continued prioritisation of vaccination for healthcare workers, adherence to infection control guidance including personal protective equipment in hospitals and easy access to PCR testing for all staff.
