@ttibsen First, let me say how sorry I am to learn your daughter is undergoing chemo for cancer. No parent wants to ever hear the dreaded C-word in connection with their child, no matter how old they are! How are you coping with this?
Being a cancer survivor has given me an entirely new perspective however. The huge medical developments over the past few years have provided much needed hope for positive outcomes.

As you’ve found out, drops in red/white blood cells and platelets are expected. Right now, because of her low resistance, she has to be super cautious to avoid any illnesses. At this point not much is known about the effectiveness on the Covid vaccine on immunocompromised patients. It is indeed a matter of ‘something being better than nothing’ But even if it is just a tiny response, it can be valuable in ramping up her immune system should she be exposed.

A suggestion would be for her to have a Spike protein antibody test run 30 days after her 2nd vaccination to see if she’s had any immune response. I’m sure she’s tired of all the blood tests but this can be done in conjunction with her other routine blood draws. Mention it to her oncologist and he can tag that onto her orders. At least it would give some indication if there’s been a response. And that still isn’t the definitive answer. There are other factors which can affect the reaction from our immune system.

May I ask what type of cancer your daughter has? Is she doing well and responding to her treatments?
Please let her know there is hope on the other side of all this! Bodies are remarkably resilient Staying strong and positive are so important. It’s that spirit of endurance which propels us forward. Lori