One of my housemates had received J&J and decided to get a supplemental mRNA shot. Here's what worked for them:
- Got to the nearest CVS.
- Ask what vaccine they have; if they only have J&J, try somewhere else.
- Say yes when they verify that this is your first shot.
- CVS asked for their name and birthdate, which they gave, but they weren't asked for ID or insurance. Possibly if you are you would need to decline?
This requires lying to the pharmacy, never something to take lightly, and there could potentially be negative medical/legal/financial consequences, but with the information we currently have it seems like something to consider.
https://www.fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/emergency-use-authorization suggest that primary care doctors have the power to vaccinate in the US. Given that off-label use of medication is generally allowed I would be surprised if you couldn't find a reasonable primary care doctor to give you a second vaccine shot if your first was J&J.
Treating this as a situation where your first sense is to lie, suggests to me that you don't have a relationship with a trustworthy primary care doctor and you should find a trustworthy primary care doctor.
Even with pharmacies my first approach would be to tell the truth.
I think it's the official policy not to ask for ID/insurance because it's important to also vaccinate the uninsured and undocumented.
I think it says two bad thinks about the primary care doctor:
Besides taking time to listen and being easy to access those two seems to me like the main things that are important about a primary care doctor.