Dear Editor,To May 2022, the COVID-19 pandemic has claimed more than 6.28 million lives, with more than 524 million confirmed cases worldwide. The recent emergence of highly transmissible Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered another major surge in both confirmed cases and deaths. 1 Ten COVID-19 vaccines have been approved by the World Health Organization (WHO) for emergency use, including the two mRNA vaccines, BNT162b2 and mRNA-1273, and two Chinese inactivated vaccines, CoronaVac and BBIBP-CorV. However, the rapid waning of vaccine-induced virus-neutralizing antibody titers and the continuous emergence of variants of concern (VOCs), including Alpha, Beta, Delta and Omicron, have created unprecedented challenges in the eradication of COVID-19 pandemic. [2][3][4] Especially, the heavily mutated Omicron variant has been well characterized to escape from most therapeutic monoclonal antibodies, as well as sera from convalescent patients or fully vaccinated individuals. 5,6 Recent work indicated that neutralizing antibody against Omicron was absent or undetectable in most Chinese populations who received two-dose inactivated vaccines, 7 while a booster dose with mRNA vaccine BNT162b2 showed significant superiority over homologous booster in protection against Omicron. 7-9 However, the two commercial mRNA vaccines, encoding the full spike (S) protein of SARS-CoV-2, are not available in mainland China. The "made-in-China" mRNA vaccine candidate AWcorna (originally termed ARCoV), which

Light-induced phosphorylation of endogenous thylakoid membrane protein can be inhibited markedly by a novel inhibitor CaMBP-10 which is discovered and isolated from plant. The inhibitory effect of BP-10 can be eliminated by addition of CaM. At the same time, the phosphorylation can also be inhibited by EGTA or CaM antagonists, such as TFP (trifluoperazine) and W-7 (N-(6-aminohexyl)-5-chloro-l-naphthalene sulfonamide). This result implies that (i) Ca(2+) and CaM most likely participate in and regulate plant photosynthesis; (ii) the kinase that catalyzes thylakoid membrane protein phosphorylation can be regulated by Ca(2+) and CaM. However, the further experiments indicate that BP-10 has no effect on dephosphorylation of thylakoid phosphoproteins.

Homologous and heterologous booster with COVID-19 mRNA vaccines represent the most effective strategy to prevent the ongoing Omicron pandemic. The additional protection from these prototype SARS-CoV-2 S-targeting vaccine was attributed to the increased RBD-specific memory B cells with expanded potency and breadth. Herein, we show the safety and immunogenicity of heterologous boosting with the RBD-targeting mRNA vaccine AWcorna (also term ARCoV) in Chinese adults who have received two doses inactivated vaccine. The superiority over inactivated vaccine in neutralization antibodies, as well as the safety profile, support the use of AWcorna as heterologous booster in China.