I also feel like there might be some immune difference. One thing I have noticed on blood work is that me and my kids who have had the tests show high levels of immunoglobulin M. That could just have been the timing of the test when we were fighting something. One kid kid also has low immunoglobulin A. We have a family history of autoimmune diseases.
I will mention blood type not because I believe it really means anything but there is a pattern on my family.
In my birth family, we are all blood type O. Our family is kind of broken, so I don’t know everyone’s details, but this I know:
Mom-not vaccinated, won’t get vaccinated and had a history of vaccine medical exemption prior to covid. She works from home, but eats at restaurants, goes to shops, etc. She wears a mask when it’s asked for but I always notice hers slipping (not on purpose). She gets tested at least once or twice a week for work, despite working at home, and has never had a positive test.
My brother is also unvaccinated, lives in a state that was hit hard but is looser with restrictions. He lives a normal life and has never had it.
I am unvaccinated. I tried several times, but had panic attacks which got worse after adverse events with my kids. I mask, don’t eat in restaurants, don’t go into crowded places. But I slept in the same bed the night my husband woke up with covid symptoms and did not get it. (Delta.) The second time he got covid, I was in a small space with him for hours and did not get it. (Late Delta, early Omicron period.) I finally got covid from my vaccinated daughter after a short exposure. Had I not had a known exposure, I would not have tested. 100 degree fever for a few hours was my only clear sign I was sick. I never felt unwell.
Husband, different blood type, B maybe. Vaccinated and had covid twice after vaccination but too early for a booster. Delta and Omicron probably. First time, low fever for a few hours followed by congestion. Second time heart palpitations which caused him to go to ER where he tested positive. No other symptoms but sinus pressure for a day.
Adult daughter, number 1. Not vaccinated. Blood type O. High IgM but low IgA in past blood tests. Not vaccinated. In Delta time, she slept in the same bed with a friend with symptomatic covid (not on purpose) and did not get it. She tested after an exposure during Omicron time and was positive. She became congested but was fine and worked remotely everyday.
College-age daughter, number 2. Not blood type O. Same blood type as husband. Vaccinated. Chronic adverse reaction. Got covid twice after vaccination during Omicron. Symptoms similar to a bad cold both times but still the worst case in our family.
College-age daughter, number 3. Blood type O. Vaccinated and boosted. Tested often, never got covid. Lived an active, normal life. Otherwise, not a great immune system.
High school age daughter, number 4. Blood type O. Late completed vaccination due to anaphylaxis type reaction after first shot. Tested often, never got covid despite exposures when family members had it. Normal, active life. In person school. Masked. Not a great immune system otherwise.