Moderna has dosed the first subjects in a Phase I/II clinical trial of its seasonal influenza vaccine candidates, mRNA-1020 and mRNA-1030. 

Both the messenger RNA (mRNA) vaccines act on hemagglutinin and neuraminidase antigens, which are two key influenza surface glycoproteins needed across the life cycle of the virus.

The randomised, dose-ranging, observer-blind trial will analyse the safety, reactogenicity and immunogenicity of one dose of mRNA-1020 or mRNA-1030 in healthy adult subjects of the age 18 years and above in the US.

This trial is expected to enrol nearly 560 subjects.

Both vaccines comprise eight mRNAs each that act on both hemagglutinin and neuraminidase at varying doses and ratios. 

Like influenza vaccine candidate of Moderna, mRNA-1010, they will target the World Health Organization (WHO) recommended strains to prevent influenza, including seasonal influenza A/H1N1, A/H3N2 and influenza B/Yamagata and B/Victoria. 

The company is pursuing an iterative method for the development of influenza vaccines, with higher levels of enhancements intended to boost immune responses and immunologic breadth. 

Though influenza vaccines licenced presently act mainly on the viral HA, in the Phase I/II trial, Moderna adds neuraminidase antigens to mRNA-1020/1030 vaccines to target both glycoproteins to offer a strong antibody response.

Moderna CEO Stéphane Bancel said: “We are pleased to apply Moderna’s mRNA platform to address the longstanding design and manufacturing challenges associated with developing seasonal influenza vaccines. 

“We believe that by targeting both hemagglutinin and neuraminidase, we can achieve broader immunity and higher vaccine efficacy against circulating influenza strains than traditional influenza vaccines.”

In March this year, the company reported that the Phase II/III KidCOVE trial of its Covid-19 vaccine, mRNA-1273, in children of the age six months to under six years met the primary endpoint.