Scan the QR code with wechat < / P > < p > to share with friends and circle of friends < / P > < p > Xinhua news agency, Sao Paulo, April 11 (reporter Gong Ruohan) < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E5%B7%B4%E8%A5%BF "> Brazil < / a > the botantan Research Institute of Sao Paulo state announced the new crown of China's science and Technology Corporation on the 11th < a target ="_ blank" href=" https://news.163.com/news/search?keyword=%E7%96%AB%E8%8B%97 "> vaccine < / a > < a target ="_ blank" href=" https://news.163.com/news/search?keyword=%E5%85%8B%E5%B0%94 "> Kerr < / a > the final results of phase III clinical trial of lefo in Brazil revised the protective effect of the vaccine on all new crown cases including mild cases without medical treatment from 50.38% published in early January this year to 50.7%, and the protective effect on new crown cases with obvious symptoms requiring medical treatment from 78% in January 7%. < / P > < p > the study, led by the butantan Institute, has been submitted to the medical journal Lancet for peer review. Kelefu vaccine was developed by Beijing Kexing Zhongwei Biological Technology Co., Ltd. and phase III clinical trial was conducted in Brazil from July 21 to December 16, 2020. < / P > < p > < p > this study shows that when < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E6%8E%A5%E7%A7%8D "> when the interval between the two doses of vaccine is longer, the protective effect of kerrefour on all new crown cases including mild cases without medical treatment can be further improved to 62.3%. The researchers believe that the optimal interval between two doses is 28 days. The study also showed that klerford had no significant effect on P.1 and p.2_ blank" href=" https://news.163.com/news/search?keyword=%E7%97%85%E6%AF%92 "> viruses < / a > also work. P. The mutation virus was first found in Manaus, the capital of Amazon state, which is a factor leading to the serious rebound of the epidemic in Brazil this year. P. The mutant virus was mainly prevalent in Rio de Janeiro and other places. < / P > < p > the researchers believe that although the two strains have multiple mutations that may affect the effect of antibodies, the results show that the neutralization effect of sera from volunteers inoculated with Klebsiella pneumoniae on the two mutant viruses is the same as that on the common strains.