(Bloomberg) -- New Zealand health authorities reported what they believe to be the country’s first death linked to the Pfizer Covid-19 vaccine.

A woman died from myocarditis, an inflammation of the heart muscle wall, following her Comirnaty Pfizer vaccination, New Zealand’s Covid-19 Vaccine Independent Safety Monitoring Board said in an emailed statement on Monday. It said myocarditis is known to be a rare side effect of the Pfizer vaccine.

The case has been referred to the coroner and the cause of death has not yet been determined. However, the board “considered that the myocarditis was probably due to vaccination,” it said. “This is the first case in New Zealand where a death in the days following vaccination has been linked to the Pfizer Covid-19 vaccine.” 

The board noted that there were other medical issues occurring at the same time which may have influenced the outcome following vaccination. Further details cannot be released while the coroner investigates.

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