don't yet qualify for booster shots...two shots (as shown in the UCSF video) provide almost NO protection against Omicron (note that she said Omicron changed things)...so, knowing that, and being a Mom, she's being prudent by not exposing them needlessly...it's just a get-together...there will be others...and as noted, when the kids' level of protection was good enough (back at Thanksgiving time) she took them to the family gathering...didn't hunker down in fear.
The Doc's head is in the game...taking the proper precautions as the situation calls for...things change (Omicron)...she changes...btw, that "6-8 month" stat you mentioned is "meaningless"...Omicron blew that out of the water (i.e. only a booster provides protection)...it's a very different COVID variant than Delta, which accounted for 99.9% (literally) of cases in the U.S. around Thanksgiving...once again, the DATA is there in the UCSF video I provided...frankly, that video has turned out to be a treasure trove of information on Omicron and how to deal with it...watch it again.
As for her 'believability'...every one of those Infectious Disease Docs in the video is applying the same precautions as she is, and I'm sure that if they had little kids of their own who don't yet qualify for booster shots, they'd stay home, too...I'll also throw in our own family ID and ICU Docs...you probably saw their guidelines for us and other family members who are headed their way on Saturday...same as the Doc we're talking about.
As for you...thanks for participating in the trials, and for making the right decision...but, breakthrough infections are more prevalent with Omicron...therefore, you could still catch COVID from someone at your gym...be asymptomatic, and spread it to someone else who is vulnerable (e.g. unvaxxed...immunocompromised, etc.)...that's why you need to be a team player. Such spreading is how the virus ends up making people very sick, or dead...there's no other way for the virus to get around...
BTW, while cloth masks were 'good enough' for the original strain of COVID and even for Delta, they aren't as effective for Omicron...another change...so up your precautions and get a KN95 mask and use it in ALL situations where you'll be close to other people...that's what we're doing as well.
Does this help?