I have always tested negative, have had it twice per IGG which is only positive if you actually had the virus. I also got it a month ago, tested negative but a friend I was with, we both came down the same day with the same symptoms 4 days after dinner together. She tested positive on day 3. I never did. I am 2 years long haulers with drastic spread of CRPS post covid (autoimmune pain disorder) And now for a month, I am bedridden with another massive spread. Antivirals helped (my doc goes by symptoms and other family results when everyone is sick!) Am now on Prednisone for 2 months to see if it helps. I tested negative. It can affect your lungs or your stomach. If it's in your stomach, swabbing your throat will probably be negative. Beyond that, if it's not COVID he feels FINE exposing his parents to any other virus? I'd be like, you people stay home if I were his parents. People get very sick from lots of flus and viruses. Seriously, if the test with a 40% false negative result is negative, potentially expose ANYONE? For a birthday? Sorry, sick is sick. Stay home. I'm looking at a wheelchair and sleeping with oxygen for 2+ years now. I'm barely retired. I think some of us just never test positive for some reason - plus these home tests are no good if they have been stored anywhere hot before they get to you. Some free ones mailed to me were already outdated! Please, stay home. Be the adult making the right decision?