For different diseases, vaccines have different production processes, and there are commonly inactivated vaccines, live attenuated vaccines, genetically engineered vaccines, etc. There are differences between different vaccines, and whether or not they can be mixed should be notified by the CDC or vaccination units. Currently, some vaccines with different manufacturers for the first and second doses can be mixed, such as the new coronavirus vaccine. The mixing of two doses of vaccine produced by the same technology from different manufacturers of the new coronavirus vaccine will not cause significant adverse effects. However, at this stage, it is recommended to complete vaccination with the same vaccine product. In case of special circumstances, such as the vaccine cannot continue to be supplied or the vaccine recipient is vaccinated in a different place, and the vaccination cannot be completed with the same vaccine product, vaccination can be completed with vaccine products of other manufacturers of the same type. The types of new crown vaccine applications include inactivated vaccine, adenovirus vector vaccine, and recombinant subunit vaccine, and different manufacturers can be selected for the two doses before and after, but the same type of vaccine should be guaranteed for both doses. In addition, if adverse reactions are serious after the first dose, you should consult your doctor whether you can continue vaccination; if you have underlying diseases or allergies, you should inform your doctor in advance and evaluate your condition before deciding whether you can receive the vaccine.