What does it mean to have a Chinese cabbage in the middle of the health code?

Vaccinate with COVID-19 vaccine. There is a model in the middle of the health code, which varies from province to province. This is the unified deployment of the province. Only people who have been vaccinated with COVID-19 vaccine will display words and patterns. There is a Chinese cabbage in the middle of the health code, which means that they have been vaccinated with COVID-19 vaccine. The design of the health code center refers to the logo of the World Health Organization.