US. I believe they got these vaccines through pharmacy chains like Walgreens or CVS. This is one of several ways people get vaccines here—it's common for seasonal flu shots especially to be available at employers (medical staff travel from one employer to the next) and pharmacies (sometimes even grocery stores with in-store pharmacies) in addition to the general practitioners' regular clinics. I think for the first dose they got it wherever was convenient—probably the pharmacy where/when they were picking up a prescription—and for the second they looked everywhere for months.