Glad I can help...Hello there! Can you be more specific about exactly where in Zona Norte? Send me a private message if you like. Your info is perfect for my situation. Much thanks.
I went to the PAMI vaccination center on Avenida Maipu in Olivos. Bring your J&J vaccine card and explain that you need a booster. They will ask you to upload your foreign vaccine card to the MiArgentina app and then take your contact info. They called me the next day to come by for the booster. I am aware of several other folks who have received their booster in this same way. My understanding from the clinic was that each day they usually have leftover doses of the second Pfizer shot that they allocate for J&J boosters. This won’t work if you received a vaccine other than J&J abroad.