On May 31, the medical preprint platform medRxiv published an article titled **"Safety and Superior Immunogenicity of Heterologous Boosting with an RBD-based SARS-CoV-2 mRNA Vaccine in Chinese Adults"**, which disclosed research data on the use of the domestically produced mRNA COVID-19 vaccine developed by Abogen Biosciences/Walvax Biotechnology as a booster shot.
This is also the first published research data on the use of a domestically produced Chinese mRNA COVID-19 vaccine as a booster shot. It should be noted that the aforementioned data only pertains to the study of this mRNA COVID-19 vaccine as a heterologous booster. The mRNA COVID-19 vaccine is currently undergoing Phase III clinical trials both in and outside of China. This clinical study on the booster shot is part of the Phase III clinical trial, and the full results of the Phase III trial have not yet been released.
Affected by this news, Walvax's stock price surged in the afternoon session on June 1, closing at 47.17 yuan per share, up 1.59%.
The mRNA vaccine for COVID-19, named ARCoVaX (or ARCoV), was jointly developed by Abogen, Walvax, and the Academy of Military Medical Sciences.2020Year6In that month, this vaccine obtained the first approval from the National Medical Products Administration (NMPA) for COVID-19.mRNAClinical trial approval for the vaccine. This yearOn January 24, The Lancet Microbe had publishedPhase I Trial Data on the Safety and Immunogenicity of the Vaccine。
The abstract of the latest published study points out that receiving homologous and heterologous booster shots of the COVID-19 mRNA vaccine is the most effective strategy to prevent the ongoing Omicron variant pandemic; the article demonstrates the safety and immunogenicity of heterologous booster vaccination in Chinese adults who have already received two doses of inactivated vaccine; compared with the technical route of neutralizing antibodies generated by inactivated vaccines, heterologous booster vaccination with mRNA vaccines as a heterologous booster shows superiority and safety in the Chinese adult population.
The article introduced that the clinical trial enrolled 300 adults aged 18 years and above. Approximately six months after the trial commenced, they were randomly assigned to either the heterologous booster group or the homologous group, with 200 and 100 participants respectively. The median age in the heterologous booster group was 43 years, while it was 40 years in the homologous group. The heterologous booster group and homologous group included 116 and 55 male participants respectively, accounting for 58% and 55% respectively. Additionally, there were no significant differences between the two groups in terms of body mass index, vital signs, or comorbidities at baseline.
Trial data show that the neutralizing antibody levels induced by heterologous booster shots are 66.59 times higher than those in the homologous booster group, with geometric mean titers reaching 293.9 and 242.4 at 14 and 28 days post-vaccination, respectively; during the same period, the homologous booster group only reached 89.1 and 64.3. Against the Delta variant, the geometric mean titers of heterologous booster shots at 14 and 28 days were 5.1 and 6.5 times higher than those of the homologous booster group. Moreover, enhanced effects were observed in both the 18-59 age group and those aged 60 and above.
However, for the Omicron variant, the average antibody titer of the participants dropped significantly to 28.1 after 28 days of vaccination, but it was still much higher than the 6.4 in the homologous booster group.
In terms of safety, injection site pain was the most reported local symptom for both vaccines. The incidence rate was 17% in the heterologous booster group and 2% in the homologous booster group (P
Among the 200 participants in the heterologous booster group, a total of 8 subjects reported grade 3 fever, with an incidence rate of 4%. In the homologous booster group, headache was the most common systemic symptom, with an incidence rate of 7%, followed by fever, with an incidence rate of 4%. Additionally, no serious adverse events were reported in either group.