Antibodies against the novel coronavirus can last at least 12 months in more than 70 percent of recovered COVID-19 patients, a study published by Chinese researchers on Tuesday showed.

The finding adds to growing evidence that vaccination, which elicits immune response in a way similar to how a live virus triggers generation of antibodies, "can effectively restrict the spread of SARS-CoV-2," the study said.

The study was conducted by China National Biotech Group under Sinopharm and the National Research Center for Translational Medicine at Shanghai Jiaotong University. It was published online by Nature Communications.

The study collected 1,782 convalescent plasma samples from 869 recovered COVID-19 patients in Wuhan, Hubei province within 12 months after diagnosis, and tested these samples for the presence of RBD-IgG, a type of antibody that strongly indicates strength of immunity against the virus.

Testing results show in nine months, levels of the antibody dropped to 64.3 percent of the initial level when they first contracted the virus, and then stabilized until the 12th month.

"It shows once immunity against the novel coronavirus is induced in human bodies, antibody levels can maintain for quite a long time," CNBG, one of the institutes conducting the research, said in an article released on its WeChat account on Wednesday.

The study is so far the longest-running study aimed at tracking antibody levels in recovered COVID-19 patients, the company said, adding the new finding will boost confidence in fighting against the disease.