New COVID-19 mRNA vaccine is safe and highly immunogenic as a heterologous booster

The Covid-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in more than 600 million confirmed cases and 6.5 million deaths worldwide.
mRNA-based Vaccines have emerged as a leading platform for Covid-19 protection and are extensively investigated in basic and clinical trials. SYS6006 (CSPC Pharmaceutical Group) is a newly investigational Covid-19 mRNA Vaccine encoding a full-length S protein sequence of the prototype SARS-CoV-2 strain and incorporating the key mutations of main epidemic variants.

In March 2023, it has been authorized for emergent use in China by the national medicinal product agency (NMPA) of China. Yet, the data from clinical trials have not been published before. Moreover, the third dose of inactivated Vaccine of Covid-19 has been proposed as the initial boosting regimen, and the second heterologous Booster (the fourth dose of the vaccine) is worth investigating. By enrolling eligible healthy subjects and convalescent Covid-19 patients, researchers from Shanghai Xuhui Central Hospital have worked and unveiled the first clinical safety and efficacy profile of SYS6006.

These results demonstrated that a modified mRNA Vaccine SYS6006 was safe and highly immunogenic as a heterologous Booster in healthy Chinese adults. The strong enhancement of antibody titers after heterologous boosting is encouraging, along with the broad-spectrum neutralizing activity of these antibodies against variants of concern, such as Omicron BA.2 and BA.4/5. The titers in the SYS6006 group were higher than those in the convalescent patients. These findings suggest the flexible use of the mRNA Vaccine as a Booster regimen, which could accelerate the end of the pandemic...Read more

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