The director of the Center for Disease Control and Prevention of China, Gao Fu, admitted that the efficacy of vaccines for the covid-19 in his country is not high, and pointed out that Beijing is studying the mixture of several or a change in the guidelines vaccination of these in order to increase the efficacy of the antigen.
Quoted today by the Hong Kong daily South China Morning Post, Gao said at a conference in the central Chinese city of Chengdu that Beijing is evaluating two avenues for improvement ” to solve the problem that the efficacy of current vaccines is not high .”
One of these would be to adjust the inoculation – either by increasing the dose, the number of doses or the spacing between them – and the other, combining vaccines of different types of technology.
According to the Hong Kong newspaper, “it is the first time that a Chinese scientist has publicly discussed the relatively low efficacy of Chinese vaccines .”
However, in an interview with the state newspaper Global Times published today, Gao considered that the media misinterpreted his words as an admission that Chinese vaccines are not very effective.
“The protection rates of all vaccines in the world are sometimes high and sometimes low. Improving their efficacy is a question that scientists around the world have to ask themselves,” Gao said, quoted by the Global Times.
“In this regard, I suggest that we think about adjusting the vaccination process, as well as the number of doses and intervals , and adopt sequential vaccination with different types of antigens,” he added.
For his part, the vaccine expert Tao Lina, present at this Saturday’s conference in Chengdu, indicated: “The levels of antibodies generated by our (Chinese) vaccines are lower than those of messenger RNA (technology used by vaccines from Pfizer and Moderna), and the efficacy data is also lower. ”
“So,” he continued, quoted by the South China Morning Post, “I think it is a natural conclusion that our inactivated virus and adenovirus vector vaccines are less effective than messenger RNA vaccines.”
At the moment, China has approved four vaccines for covid-19 for emergency use: two developed by the pharmaceutical company Sinopharm (both of inactivated virus), one by Sinovac (inactivated virus) and another by CanSino (viral vector non-replicating).
In the case of the Sinovac vaccine, clinical trials were conducted outside of China that left different efficacy rates: while the trials conducted in Turkey showed an effectiveness of 91.25%, the data provided by Indonesia pointed to 65.3 % and Brazil lowered the percentage to 50.4%, a week after announcing 78%.
The effectiveness rates of Sinopharm vaccines are between 72.5% and 79%, while CanSino claims that its antigen is 75% effective.
On March 31, the group of experts of the World Health Organization (WHO) that studies vaccines against covid-19 explained that it is finishing its analysis of those developed in China by Sinovac and Sinopharm, and in the coming days confirm whether or not you authorize their emergency use.