After a revised UK advisory accepted Covishield as a valid vaccine but said double-jabbed Indians still have to quarantine because of 'vaccination certification issues', Dr RS Sharma, National Health Authority CEO & Head of the Cowin App, tells NDTV "UK is interested in knowing the CoWIN architecture. Our technical team has interacted with the UK technical team. Two meetings have taken place and during those discussions, there were absolutely no concerns raised. CoWIN is one of the best applications in the vaccination area in the whole world, it is a fact. The entire process is digital, what comes out is a digital certificate that can be verified for its authenticity, integrity and truth. We have been very aligned and conscious of the fact that digital certificates will be needed, so the entire process from Day 1 has been completely digital."