The Hospital Authority said six of the 12 cases were hospitalized patients while the rest passed away in the emergency department.
With the additional miscarriage cases, Hong Kong has now seen 23 miscarriage cases after vaccination.
From February 26, when the city’s vaccination campaign started, until last Sunday, the city recorded 80 deaths following vaccinations.
Official data shows 0.58 deaths were recorded for every 10,000 people among the inoculated group, while the figure was 19.06 for non-inoculated people.
Meanwhile, in the vaccinated population, authorities have so far recorded 244 cases of strokes, 90 cases of heart attacks.