Why is there no manufacturer for my third vaccine?

The information of the third dose of vaccine has not been accurately verified by the manufacturer. From the point of view of immunology, the production technology and immune mechanism of inactivated COVID-19 vaccine from different manufacturers are the same, which is supported by sufficient data. If COVID-19 inactivated vaccine from the same manufacturer can't be vaccinated because of the vaccine supply problem before, the second or third shot of COVID-19 inactivated vaccine from the same production process and different manufacturers can be vaccinated completely, and the immune effect after vaccination is basically the same, and the vaccine safety can also be guaranteed.