China, eager to build good will, stepped in, promising to provide more than 255 million doses, according to Bridge Consulting, a Beijing-based research company.Half a year in, however, that campaign has lost some of its luster. Officials in several countries have raised doubts about the efficacy of Chinese vaccines, especially against the more transmissible Delta variant. Indonesia, which was early to accept Chinese shots, was recently the epicenter of the virus. Others have complained about the conditions that accompanied Chinese donations or sales.The setback to China’s vaccine campaign has created a diplomatic opening for the United States when …
