Have you considered that this person might be seriously immunocompromised? I have a friend who is a kidney transplant recipient. He's in his early 50s and single and was a bit over a year post transplant when Covid hit. He was really just starting to feel good and was hitting his stride, and then Covid flipped his world upside down. He waited, like the rest of us for the vaccine and has received both doses of the Moderna vaccine. And he has not generating any detectable antibodies to the virus.
https://www.sciencedaily.com/releases/2021/03/210324170811.htm
My DH is 6 years post kidney transplant. (has it really been that long???
) He has been at home since mid-March 2020; only has gone out to a Walmart once (to pick up a heavy chair that was delivered to the FedEx depot in the store) and to the doctor/lab visits. Other than that, he does walks in our neighborhood (we live next to a 'trail'). He has been wearing a mask anytime he steps out of the house for anything, santizes if he can't wash hands, washes when he can. His immune system is very delicate; he's battled HBP since his kidneys failed; and he's developed diabetes since the transplant.
While catching COVID might be just a 'cold' to some, to him, it could be a death sentence. Just as catching measles or mumps or even the flu could be. So he's extra cautious. He's always done the hand sanitizer/hand washing thing; avoiding touching others; he doesn't get ice or fountain drinks (only bottled, and he cleans the bottle before opening), or fresh veggies at a restaurant (do they clean them properly? he doesn't know). He avoids the sun (long sleeves, pants and hats, and sunscreen), which is fun in FL. Things like that are just a part of life now, since the transplant. The COVID situation...just added another small layer onto his routines (the masks).
Anyways, they are going to check his antibodies at the beginning of May, as that puts him at 2ish months post vax. He got his vaxx Feb 1/Mar 2, Moderna.
He goes back to work in office next month, as we will all be vaccinated by then. He's trying to get HR to give him some extra space in the office, either by expanding his cubical by another 3-4 feet, or by giving him a small office; we would pay for an air filtration thing to go there. His office took advantage of the year away, and expanded; they now have 2 floors in the office building; and since they were upgrading the electrical/wiring anyways, they had the HVAC system upgraded, with really good filtration units.
His office has had 4 people test positive; all 4 are anti-mask, anti-vaxx, conspiracy theory type people. One went on vacation in December, out of state; 1 went to Miami Beach last month for 'spring break' (although he's at least 26); 1 attended an out of state wedding that was no-mask, indoors, over 100 people, back in January; and the last thinks he got it because of conspiracy to get a 5G chip in him (but it was most likely that he caught it as he went about his 'daily life' with no precautions) last fall. These are the only 4 out of over 70 in the office, who have come down ill, and DH is the only one still working from home (everyone else went back in January).