My sister and their family also got sick lately. They were saying that it was my niece that brought it back home and they all got affected. I think these are just other strains of Covid going around the world. Since a lot of us have been vaccinated or survived it, it isn't as bad and just comes as a flu. I do hope your daughter gets better soon.
Flus and viruses go around. For the vast majority of people, Covid wasn't much more than a flu, for many it was even less than a flu. There are so many problems with isolating ourselves from one another.