We are currently in Switzerland (not on a sit, just a vacation). Our flights were Tampa to Dallas/Fort Worth; DFW to London Heathrow; London Heathrow to Geneva. We were only at Heathrow for about 2.5 hours. We were required to have a covid test taken 3 days prior to the departure flight for entry into Heathrow (even though it was merely in transit) - it could have been either PCR or rapid Antigen, and written results. We also had to fill out a form for a QR code - again, even though merely transiting through the airport. Though Switzerland did not require a covid test for entry, we did have to complete a health form in which we indicated we were fully vaccinated. We received a QR code in return which we presented at immigration. We also brought along our vaccination cards which have come in very handy. Here in Switzerland, you cannot eat indoors at a restaurant without proof of vaccination - some restaurants have accepted our vaccine cards. It’s important for everyone traveling to know the rules of their destination country, as well as transit countries…and of course, the requirements for returning home! I felt so sorry for the people at LHR and GVA who arrived without the proper forms…Good luck all!