Moderna will be initiating a Phase III trial of its flu and Covid-19 vaccine later this year after a Phase I/II trial showed the combination vaccine was as effective as individual doses.

The company, which helped develop one of the world's first Covid-19 vaccinations, has announced positive results from its Phase I/II trial of mRNA-1083.

Chief executive officer of Moderna, Stéphane Bancel, said the positive results will help guide the Phase III trial beginning later this year and is targeting potential regulatory approval in 2025.

"Flu and Covid-19 represent a significant seasonal burden for individuals, providers, healthcare systems and economies,” Bancel said. “Combination vaccines offer an important opportunity to improve consumer and provider experience, increase compliance with public health recommendations, and deliver value for healthcare systems.”

The Phase I/II clinical trial (NCT05827926), which is ongoing, is a randomised, observer blind study evaluating the safety and immunogenicity of mRNA-1083 compared to a standard dose of influenza vaccine, Fluarix, in adults 50-64 years of age and against an enhanced influenza vaccine, Fluzone HD, in adults 65-79 years of age. For both age groups, mRNA-1083 was compared against the Spikevax booster.

Results show antibody titers similar to individual doses

mRNA-1083 achieved haemagglutination inhibition antibody titers similar to or greater than both licensed quadrivalent influenza vaccines. It also achieved SARS-CoV-2 neutralising antibody titers similar to the Spikevax bivalent booster.

Reactions after mRNA-1083 administration were similar to the standalone Covid-19 vaccine group in the trial. The majority of adverse events were reported as grade one or two in severity. Grade three reactions were reported in less than 4% of participants aged 50 and above. No new safety concerns were identified compared to the standalone vaccines.

mRNA-1083 is a combination of mRNA-1283 and mRNA-1010

mRNA-1083 stimulates the immune system to generate antibodies against influenza virus haemagglutinin (HA) glycoprotein and SARS-CoV-2 spike glycoprotein, preventing influenza and SARS-CoV-2 infections. It is a combination vaccine of mRNA-1283, which encodes the Receptor Binding Domain (RBD) and N-Terminal Domain (NTD) of the spike protein and mRNA-1010, encoding haemagglutinin (HA) glycoproteins of influenza A/H1N1, A/H3N2, and influenza B/Yamagata and B/Victoria-lineages.