“Big Brother” is a game show in which a group of contestants, referred to as “HouseGuests,” live in a custom-built house (actually a TV set) and are constantly under video surveillance. It has been an international phenomenon for over 20 years. News from the outside is not allowed to reach the HouseGuests; they’re isolated from all broadcasts and newspapers, even as the world faces the uncertainty of the COVID-19 pandemic. The World’s Bianca Hillier reports.