Some people – but not all – who are receiving certain types of drug treatments, including those which suppress the immune system, are also in this group of very vulnerable people.
Mae rhai – ond nid pawb – sy’n derbyn mathau penodol o driniaethau cyffuriau, gan gynnwys y rhai sy’n amharu ar y system imiwnedd hefyd yn y grŵp hwn.