You (the household member) must follow the UK Government self-isolation guidance self-isolation guidance and self-isolate for at least 7 days from the start of your symptoms.
After 7 days, if you do not have a high temperature, you do not need to continue to self-isolate. If you still have a high temperature, keep self-isolating until your temperature returns to normal. You do not need to self-isolate if you just have a cough after 7 days, as a cough can last for several weeks after the infection has gone.
The key worker (and other household members) must self-isolate until 14 days from start of symptoms in the household member with COVID-19; if any other household member, including the keyworker develops symptoms, they must follow the 7 day isolation rule themselves, as above.
If you have a POSITIVE test result for COVID-19 infection but have never had any symptoms:
Even though you have not had symptoms, you can still pass the virus to others and must still self-isolate.
The date your COVID-19 test was taken should be used as the first day of the 7 day self-isolation period. If you subsequently develop symptoms within that 7 days, then use the date of onset of your symptoms as the first day of your self-isolation period. The same date (either your test date or the date of onset of your new symptoms) is used as the first day of the 14 day isolation period for your household members (including the key worker).