How long to isolate for?

It's 10 days, or 5 days since being fever free, whichever is the longest.

No requirement for a negative test to end isloation. PCR will remain positive for sometime, antigen will only be positive if she is likely to still be contagious.

This is a quote from the HSE website.

In most cases, you can stop self-isolation if you have had no fever for 5 days and it has been 10 days since you first developed symptoms.

https://www.citizensinformation.ie/en/health/covid19/covid19_isolation_and_restricting.html

My question is why is it 10 days though?

What's the 10 days based on or What's the sciences behind it?

Thanks. 😊

The 10 days was based on contact tracing studies (ie when was transmission occurring from positive cases) and viral culture studies (how long were viral titres likely to remain infectious) Based on original 'wild' type virus, probably different for Delta.

You should be contacted by the HSE and sent 3 antigen tests to do, every second day, over 5 days (1, 3, 5)

If you are a household contact, in addition you should restrict your movements until your 3rd negative antigen test.

The HSE advice is only regarding a fever, so there is no reference to other symptoms, even though many Covid +ve never have a fever at all.

The CDC (USA) is no fever and other symptoms improving - which makes a lot of sense. Many people will have some persistent symptoms but will not be contagious, but improving symptoms suggests the immune system is getting the better of the virus, not the other way around!

A negative antigen test would be a good marker that your colleague is not longer contagious.