In order to return to some normality it is essential to track corona virus history of everybody. Not very democratic but also very un-avoidable.
What we urgently need is the vaccines and multiple repeated antibody testings.
Medical authority should develop public/private key pairs one for each person an keep the private keys.
All virus related test results should be entered in the block-chain similar to bitcoin transactions now.
In near future when the vaccine is finally developed vaccinations and subsequent antibody tests should be entered in the block chain too.
Once somebody has finally recovered or vaccinated and is medically proven not to be the virus spreading carrier that person should be issued a machine readable ID card with photo ID signed by private key kept by the medical authority.
Special network connected check block chain nodes will allow quick worldwide validation of this ID cards quickly
Only those person can be allowed to travel internationally and provide essential services for other people.
Medical community will develop better tests and hopefully a vaccine soon, but information specialists have to provide non mutable and very robust worldwide tracking system of persons who have already acquired the corona virus immunity.
That is where block-chain could help solve this crisis sooner.
I would be interested to hear some other proposals on using block-chain in along those lines.