Just did a 4 day trip to Krabi, Koh phi phi. My estimate based on severe raspy coughing is that 10% of tourists have COVID. Most foreigners do not wear masks, on the airplane, ferry, or out at night. The pool party was well attended. Maybe you get sinus drainage, sore throat, mild fever, and that cough lasting more than 1 week. Worse thing is loss of taste and smell and you hope that goes away in under 2 months.