A new medical paper has reported what it believed to be the first case of Covid-19 reinfection in Ireland.
A report in the Irish Medical Journal details the case of a 40-year-old health care worker, who was confirmed to be infected with the virus for the second time, seven months after her first infection.
The paper, co-authored by Dr Cillian De Gascun of the National Public Health Emergency Team (Nphet), states: "To our knowledge, this is the first report of reinfection from Ireland."
The woman did not need hospital attention during her first infection, but was unfit for work due to "significant headaches and persistent fatigue".
The paper, Genomic Evidence of Sars-CoV-2 Reinfection in Ireland, states that "symptoms were milder and recovery was faster on the second episode".
Seven months after her first infection, the patient presented with symptoms including cough, headache, sore throat and fatigue.
"She reports a post viral wheeze controlled with low dose inhaler" the report states.
It notes that Covid-19 was not detected when the woman underwent a PCR test 15 days previously.
The paper warns that lasting immunity from Covid-19 "may not prove universal" in those previously infected or vaccinated.
Citing data from UK studies on health care workers, it says preliminary data suggests that Covid-19 infection is associated with an 83% lower risk of reinfection.
The median protective effect last "up to five months from primary infection".
The authors warn that the consequences of re-infection among health care workers are significant "due to the impact on service delivery and cross infection in other health care workers and patients."
"Further study into the level and duration of immunity conferred by both infection with, and vaccination against, Sars-CoV-2 is required to inform future vaccination campaigns and infection prevention and control policy," the paper concludes.