text: (i) these Regulations, or 
  (ii) an enactment which, in Scotland, Wales or Northern Ireland, has the effect of 
  requiring the isolation or quarantine of persons who have been outside the common 
  travel area, for any of the purposes described in sub-paragraph (b); 
  
  (b) for the purpose of— 
  
  (i) preventing danger to public health as a result of the spread of infection or 
  
  contamination with coronavirus or coronavirus disease, 
  
  (ii) monitoring the spread of infection or contamination with coronavirus or coronavirus 
  
  disease, or 
  
  (iii) giving effect to any international agreement or arrangement relating to the spread of 
  
  infection or contamination with coronavirus or coronavirus disease; or 