Researchers have documented what they believe to be the first known case of COVID reinfection in Ireland.

A study published in the Irish Medical Journal reports that a 40-year-old healthcare worker was diagnosed with the virus for the second time last November.

The woman was originally diagnosed with the virus seven months earlier. in April.

The study notes that her symptoms were milder and her recovery was faster the second time around.

While cases of COVID reinfection have been reported in a number of other countries, this study concerns the first documented case in Ireland.

The Health Protection Surveillance Centre (HPSC) has since recorded hundreds of others.

The woman first presented in April of last year with a fever, headache, shortness of breath, sore throat and reduced sense of taste.

She was confirmed with COVID-19 through PCR testing and, while she was never hospitalised, she was unfit for work for period of four weeks and suffered significant headaches and persistent fatigue lasting four months.

Seven months later she presented with a cough, headache, sore throat, fatigue and muscle pain. Her COVID-19 was again confirmed through PCR testing.

Her symptoms were milder and she was able to return to work after her two-week isolation period.

The authors note that the virus was not detected when the woman underwent a separate PCR test 15 days previously.

The authors note that COVID-19 reinfection is not well characterised and call for further study into the level of immunity conferred by both infection and vaccination.

While the researchers believe this to be the first documented case of reinfection in Ireland, the Health Protection Surveillance Centre (HPSC) has since recorded hundreds of others.