Hello and thanks for posting,

Our standard advice is that anyone who has obvious symptoms of cough, colds, sneezing, or tummy bugs, do not visit someone who may have low immunity.

There is NHS information about Strep A here

So, if you are feeling well, then the risk should be low. There is always an option of wearing a N95 face mask (as used in covid), if your nasal droplets are a concern. Covering your mouth with a tissue, when coughing or sneezing is sensible. Otherwise, sensible precautions such as regular hand washing whilst visiting your friend should be adequate. 

I hope that this helps, 

Best wishes,

Vanda