Rotunda research reveals persistence of Covid-19 antibodies in health care workers up to six months after infection

Researchers at the Rotunda Hospital have demonstrated the persistence of anti-SARS-CoV-2 (Covid-19) antibodies in 91% of infected healthcare workers at six months post PCR confirmed infection.

Using a diagnostic test developed and manufactured by Irish company Trinity Biotech, the research team collected serum samples from both symptomatic and asymptomatic healthcare workers employed at the busiest maternity hospital in Europe, from March to September 2020.

Almost 600 blood samples were collected from more than 250 participants, including those staff presenting for symptomatic Covid-19 swabbing, asymptomatic healthcare workers volunteering as control participants and a further group of hospital staff with a previously laboratory confirmed diagnosis of Covid-19.

The study found that:

• Antibodies to SARS-CoV-2 were detected at Day 50 in 98% of participants who had a confirmed positive swab result.
• Antibodies persisted in these participants at Day 100 post-confirmation of infection.
• This figure dropped to 91% by Day 160+, highlighting that the vast majority of HCW had detectable levels of antibodies in their serum up to 6 months post-infection.

The incidence of SARS-CoV-2 infection in healthcare workers was significant during this timeframe, with 14% of study participants testing positive via RT-PCR.

The seropositivity rate, which shows how many participants had detectable antibodies to SARS-CoV-2 in their samples, was shown to be 98% in the symptomatic group of confirmed cases, while the rate of asymptomatic seropositivity was 8%.

The duration and longevity of these antibodies and whether this infers immunity is still unclear and continues to evolve with ongoing research.  Antibody testing of serum samples in the CAST study was performed using the Trinity Biotech Captia™ SARS-CoV-2 IgG ELISA assay.

Commenting on the results Prof Fergal Malone, Master of the Rotunda Hospital said:

“The CAST study presents important data on healthcare worker infection during the ongoing global pandemic and includes information on infection clinical symptoms and the importance of robust serological screening methods.

“We are proud to work with Trinity Biotech, an Irish company in order to bring a reliable, accurate and sensitive serological test for SARS-CoV-2 to market at this challenging time which will have a meaningful impact on the long-term management of the COVID-19 pandemic”.