2021-05-13 07:05:56 GMT2021-05-13 15:05:56(Beijing Time) Xinhua English SERRANA, Brazil, May 12 (Xinhua) -- The small Brazilian town of Serrana, with a population of some 50,000, has been proud of undertaking a mass immunization campaign with the Chinese-made vaccine, according to Serrana Mayor Leonardo Capitelli. The CoronaVac vaccine developed by Chinese pharmaceutical firm Sinovac is the most prevalent in Brazil through cooperation with the Sao Paulo-based Butantan Institute, a state government-funded scientific research center. The vaccine accounts for almost 80 percent of all the doses applied in Brazil. Located in the southeast state of Sao Paulo, Serrana is a sugarcane-producing agricultural town. Project S is the Butantan-led scheme to vaccinate the entire adult population of 27,772 and verify the vaccine's effectiveness against COVID-19.