Moderna has initiated dosing in a Phase II/III study of its Covid-19 vaccine candidate, mRNA-1273, in healthy adolescent participants aged between 12 and 17.

Co-developed by Moderna and NIAID Vaccine Research Center investigators, the mRNA vaccine encodes for a prefusion stabilised form of the Spike (S) protein of SARS-CoV-2.

Conducted in partnership with the US Biomedical Advanced Research and Development Authority (BARDA), the study will have 3,000 participants in the US.

The randomised, controlled study will analyse the safety, reactogenicity and immunogenicity of two 100μg doses of mRNA-1273 given 28 days apart.

Each participant will be given either placebo or mRNA-1273 and will be followed for 12 months after the second vaccination.

The primary endpoint of the study will be safety and reactogenicity of the vaccine, while its effectiveness will be inferred through obtaining a correlate of protection (if established) or immunobridging to the adults.

Moderna CEO Stéphane Bancel said: “Our goal is to generate data in the spring of 2021 that will support the use of mRNA-1273 in adolescents in advance of the 2021 school year.

“We are encouraged by the interim and primary analyses of the Phase III COVE study in adults ages 18 and above and this adolescent study will help us assess the potential safety and immunogenicity of our Covid-19 vaccine candidate in this important younger age population.”

Last month, Moderna announced that the Phase III COVE study of mRNA-1273 met the statistical criteria pre-specified in the study protocol, with a vaccine efficacy of 94.5%.

Meanwhile, in a separate development, clinical-stage biotech firm Tychan is set to begin a Phase III clinical trial of a novel monoclonal antibody, TY027, for Covid-19 in Singapore.

The novel therapy is being analysed for treating Covid-19 patients to slow disease progression and speed up recovery, and also to potentially provide temporary protection against the SARS-CoV-2 virus.