Maybe she received the 4th (updated Pfizer) dose on the 7th? That is the day the NHS started the latest round per the following link - https://www.pmlive.com/pharma_news/nhs_to_move_ahead_with_pfizerbiontech_bivalent_covid-19_vaccine_roll-out_1454869
Maybe she received the 4th (updated Pfizer) dose on the 7th? That is the day the NHS started the latest round per the following link - https://www.pmlive.com/pharma_news/nhs_to_move_ahead_with_pfizerbiontech_bivalent_covid-19_vaccine_roll-out_1454869