Ars reported a very complicated ransomware attack which has caused Ireland to shut down most of the major IT systems running its national health care service, leaving doctors unable to access patient records and people are unsure of whether they should show up for appointments.

Paul Reid, chief executive of Ireland’s Health Service Executive (HSE), told to a national radio show that the decision to shut down the systems was a “precautionary” measure after a cyberattack that impacted national and local systems ‘involved in all of their core services.”

“This is having a severe impact on our health and social care services today, but individual services and hospital groups are impacted in different ways. Emergency services continue, as does the @AmbulanceNAS [National Ambulance Service],” health minister Stephen Donnelly wrote on Twitter.