A woman receives a dose of COVID-19 vaccine at a vaccination site at Anhui Agricultural University in Hefei, east China's Anhui Province, May 13, 2021. Photo:Xinhua

CanSino's vaccine, the only single-dose vaccine approved in China, is set for high levels of production, raising hopes that the country can achieve herd immunity by year-end. Residents of at least seven provincial-level regions have begun the inoculation process, and there is no upper age limit. 

Based on technology similar to that of Johnson & Johnson's shot, CanSino's vaccine requires only one shot to provide protection. The other three vaccines approved by China require two or three doses. Residents in Beijing, Shanghai and Tianjin municipalities, as well as East China's Zhejiang and Anhui provinces, and Central China's Henan and Hunan provinces, are eligible for the vaccine, the Global Times learned. 

China is expected to achieve herd immunity by the end of the year, said Shao Yiming, a leading physician and imunologist from the Chinese Center for Disease Control and Prevention, on Tuesday. More than 421 million doses of COVID-19 vaccines have been administered in China as of Wednesday, media reported.

The latest financial report from CanSinoBIO showed that the company's third plant in Tianjin has been put into operation and is expected to produce 200 million to 300 million doses per year. Previous media reports said its total annual capacity is to reach 500 million to 700 million doses. 

CanSinoBIO announced on Monday that it will invest over 1.1 billion yuan ($170 million) along with Shanghai Sunway Biotech Co to expand production capacity in Shanghai. 

Due to the convenience of only needing one shot, the vaccine has gained popularity among the public. Zhou Yanqing, an official from a health center in Shaoxing, Zhejiang Province, told the media that the center vaccinated nearly 200 people on May 12. "Apart from those who received a second dose of a different vaccine, almost all the rest of the people chose the one-dose vaccine," the official said. 

The CanSino's vaccine is different from inactive vaccines in terms of technical principles and vaccination procedures, but the method of vaccination, age range and safety levels are all the same. 

The third-phase clinical data shows 28 days after inoculation, the overall protection rate is 65.28 percent and the protection rate for severe cases is 90.07 percent. It is also effective in dealing with variants, thepaper.cn reported, citing officials from the Shanghai Center for Disease Control. 

But compared with other vaccines, many people who were injected with CanSino's vaccine told the Global Times that they had an obvious side effect - fever. Similar comments could be frequently seen on the topics on Sina Weibo, ranking top on Tuesday night. 

"As CanSino has not yet published detailed phase III clinical data, we can only compare its phase II data with the inactivated vaccine data. In an experimental team, 16 percent of volunteers had fever and 28 percent had headaches. But in an experimental team using Sinopharm's inactivated vaccine, the two figures were 4 percent and 1 percent," said Zhuang Shilihe, a Guangzhou-based immunological doctor. 

But Zhuang said it is acceptable to have severe side effects, since the single-dose vaccine induces a stronger immune response. "Some adverse reactions show that our bodies are responding to the vaccine."

Tao Lina, a Shanghai-based vaccines expert, shared with the Global Times a comment by an acquaintance who attended a global COVID-19 vaccine R&D summit. The person said that the antibody retention time after vaccination was not promising. Methods of enhanced immunization (one more dose of the same vaccine) or sequential immunization (one more dose with a vaccine from a different technical route) are being studied.

China is pushing ahead its national vaccination campaign with more than 10 million doses being administered per day for seven consecutive days. The daily number increased, especially after new sporadic cases were discovered in Anhui and Liaoning provinces, 15.05 million doses were injected on Monday, a record daily high.