Chief reviewer in charge of vaccines at the Center for Drug Evaluation of the Chinese National Medical Products Administration, Li Yingli, stated on Saturday that the antibody-dependent enhancement (ADE) effect has not been reported in any of the clinical trials of the vaccine developed by China, state newspaper Global Times reported.

The antibody-dependent enhancement (ADE) effect is a phenomenon in which the antibodies bind to the surface proteins that are infected by the virus but do not inactivate the virus. This can exacerbate immune responses and lead to severe cases of the disease.

He told Global Times : “ADE is a problem that we are particularly concerned about. If it occurs in subjects after vaccination, the vaccine must be given up.”

According to Gao Fu, the head of the Chinese Center for Disease Control and Prevention, ADE is one of the biggest challenges that vaccine development is facing currently.

Whether ADE will occur or not for novel coronavirus has not yet been determined, and there is no data for reference at home or abroad on this question, Gao noted. “We should still stay alert to ADE in vaccine development.”

Gao added that reinfection cases should not be over-interpreted and people should maintain an optimistic attitude to a coronavirus vaccine.

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Reinfection needs to be studied

Meanwhile, other Chinese experts believe that a study should be conducted on reinfection cases.

“By studying such cases, we can find out what kind of immunity is the most important and essential against the novel coronavirus,” Dong Chen, director of the Institute for Immunology of Tsinghua University, said.

Dong also cautioned people saying that the resurgence of novel coronavirus can happen in winter, especially in overseas regions.