England's National Health Service (NHS) said it is working on a system to prove coronavirus vaccination status similar to Israel's "green passport" program, according to the BBC.The certification would also display recent negative COVID-19 tests, or whether they have tested positive within the past six months – the latter most likely providing a natural immunity.Like the green passport program, England's version will also be "time-limited," the NHS said. Israel is suggesting a six-month window, following more testing. The system is an attempt to reopen concert venues and sporting events to the public. The British government also claims to be working on separate ways to safely reopen mass events to the public.The first few events that will run under this program are the FA Cup final and the World Snooker Championship. Movie theaters and nightclubs are also on the list for the pilot program.In Israel, green passports are required to enter certain places and to participate in certain activities. It is granted to those who are a week past their second coronavirus vaccination, or people who have recovered from the virus and are currently not eligible for the vaccine.