The city of Nanjing, capital of east China’s Jiangsu province, began on Wednesday to deliver COVID-19 booster shots based on technologies different from those used in initial inoculations in the country, in an effort to reinforce herd immunity against the disease.
The method, known as sequential immunization, targets people over 18 years old who are fully vaccinated with one of the three inactivated vaccines produced by Sinopharm and Sinovac Biotech, according to the National Health Commission. Two shots are required for full vaccination.
Instead of receiving an additional shot developed with the same technology, which has been standard practice in the country since October, people eligible for a booster now have wider choices. They can get a protein sub-unit COVID-19 vaccine made by Anhui Zhifei Longcom Biopharmaceutical or a viral vector vaccine from CanSino Biologics.
Protein sub-unit vaccines use a sub-unit of virus antigen to trigger an immune response, and viral vector vaccines use a modified version of a different virus to instruct our cells to fight the virus, according to Chinese researchers.
