A few things:
(1) When was your last dose of vaccine? Were you already in treatment?
(2) In general, solid tumor cancer patients—even those on chemo—mount a decent response to the mRNA vaccines. Not quite as strong as healthy controls, but decent. That said, everyone is different, and the Delta variant is still somewhat of an unknown. You haven’t posted a signature, so it’s a little hard to say much specifically, but youth (even relative youth), absence of co-morbidities (including obesity), good levels of vitamin D, female gender, solid blood counts, general fitness, and non smoker status are all advantages (some of these apply to vaccine response, some to fighting disease, and many to both). (With the CBC, I would look at your lymphocytes in particular, and not so much your neutrophils, which we usually concentrate on as cancer patients undergoing chemo.) You likely have a recent CBC (blood draw).
(3) By the way, FOLFOX is not considered particularly damaging to the immune system (as chemo regimens go) so with luck your immune system is not too bad.
(4) Are you on a blood thinner, in particular enoxiparin (Lovenox)? If so, great, there is lots of evidence it is protective against COVID in various ways.
(5) You’re right to talk to your oncologist ASAP. Presumably they have an on-call person? You will need to ask if they view you as immunocompromised (you likely are, at least to some extent), and what your best course of action is. If it were me, *and I noticed any symptoms*, I’d get tested and, if positive, start advocating hard for monoclonal antibody treatment (3/4 available in the US are effective against Delta, but it must be administered early in the course of disease). (You may want/need to get tested regardless of symptoms, follow your doctor’s advice.) You may also want to ask about Lovenox if you’re not on it—you can say you heard from some nut on the Internet ; ) that low molecular weight heparin was a good idea for COVID patients because of its anticoagulant and anti-viral properties.
(6) All THAT said, with luck you’ll miss out on getting infected. But know also that solid tumor patients also generally do ok with COVID, and some studies I’ve seen don’t assign much increased risk even to active chemo. But I would err on the side of caution and discuss the situation with your doctors ASAP.
(7) Oh yeah, and follow any applicable quarantine, testing, and masking guidelines.
Sorry this occurred and Good luck!
7/19: Rectal cancer: Initially staged as IIIA, T2N1M0
Initially approx 4.25 cm, low/mid rectum, mod. well diff. adenocarcinoma
8/22 -10/14 4 rounds FOLFOX neoadjuvant, 3 w/Oxiplatin (lots of side effects/reduced size est. 70-75%)
neoadjuvant chemorad 11/19
4 rounds of FOLFOX July-August 2020
ncCR found 10/20; multiple biopsies negative
TAE 11/20, small amount of tumor removed, lung nodules orig id’d 6/20 stable Nov 2020
Chest CT 3/30/21 small growth in 2 nodules (3 and 5mm)
Stable in 6/28 scan.