"Covid will not suddenly disappear," Prime Minister Boris Johnson told Parliament on Monday, adding that "restrictions pose a heavy toll on our economy, our society, our mental well-being."

Cutting the isolation for positive cases to five days could lead to more infections if people don't take masking seriously. A testing requirement would have made the policy safer, experts say.

Here's how to self-isolate, what the new quarantine guidance means for your household, and which symptoms signal you need immediate emergency care.