Lot of issues. Different countries , airports and ports have different vacination/quarantine requirements. That keep changing from day to day. Imagine most of your ships, planes, pilots or seafarers getting sick or stuck in quarantine somewhere or the other for almost a year now.
Things get better as govts wake up to such non uniform policies. In the mean time expect all kinds random break downs.
Things get better as govts wake up to such non uniform policies. In the mean time expect all kinds random break downs.