Covid-19 Certificate QR Code Scan on Smartphone in Hand. Health Passport. Man in Medical Mask showing a smart phone. Cartoon vector stock illustrationCovid-19 Certificate QR Code Scan on Smartphone in Hand. Health Passport. Man in Medical Mask showing a smart phone. Cartoon vector stock illustrationA man scans a QR code for the government’s ‘Leave Home Safe’ app, used for contact tracing amid the Covid-19 pandemic, to enter Immigration Tower in Hong Kong on December 9, 2021. (Photo by Bertha WANG / AFP)