Teenagers live in a world where school and exams are valued very highly. The decision to cancel A-level and GCSE exams may therefore create a lot of anxiety. Make sure you talk to them about it and encourage them to continue learning. If your school has created online materials, make use of them.
Accept that they will also need to talk with friends and process what is happening around them, so tune into the value of the technology they are glued to, and actively encourage face time and group chats. It is best to talk with teenagers as the near-adults they are, emphasising the positives - the experts are working round the clock.