A COVID transmission anecdote and live test of my family’s airborne transmission precautions:

My son’s teenage friend rides in a car for ~30 min, masked the whole time. The next day the driver tests positive. Teen is triple vaxxed.

At day two and three post exposure the teen has a negative rapid antigen test. They had plans to come to our house Sunday (with everyone present doing rapid tests) but given the exposure I ask to postpone. Rapid tests aren’t perfect!

Around four days post exposure the teen has a negative PCR test. That’s gotta mean the risk is low, right?

Being masked, the exposure doesn’t count as a “close contact” so the teen is still at school with my son.

Seven days post exposure the teen does another rapid antigen test and this time it’s positive! No symptoms yet.

My son has been sitting next to the teen and eating lunch with them for the past three days. What’s the probability my son is now infected?

Well, my son has made some key decisions (his, not mine):

• Got boosted the first day he was eligible, 6 weeks ago
• Always wears an N95 mask at school
• Eats lunch outside, keeping >1m distant from others (even in our record cold temps, which my wife and I said was nuts).

I figure he’s got a pretty good shot at having protected himself, but with such prolonged exposure the risk has still got to be significant.

My son will be doing rapid tests daily to help reduce the risk of him spreading it to someone else at school. The first is negative.

My son had another negative rapid antigen test and this morning a negative rapid molecular test (Lucira check-it).

For the record, my son continued to test negative on daily RATs. We stopped regular testing about 4 days after end of symptoms (though I admit to testing only every other day during those 4 days). We also just did an antibody test and saw no hint of IgM (only IgG from vaccine).