The government has announced a significant expansion of the shielding list - this is based on a recent study looking at which medical conditions and other factors (BMI, ethnicity, deprivation) mean that people are likely to develop severe problems if they catch Coronavirus.
There are many news reports on it appearing - for example:
Some of these people should start to get letters/text messages over the next few days but there has been no official update on the government website as yet. I will publicise it when we are notified.
Please watch this space