The second mRNA COVID-19 vaccine developed by German biopharmaceutical company CureVac and its British partner GlaxoSmithKline (GSK) has demonstrated improved immune response and protection than its first vaccine, according to a new study.

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The study, yet to be peer-reviewed and posted on pre-print server bioRxiv, shows that CV2CoV has higher neutralising capacity against a range of variants, including the Beta, Delta and Lambda variant and the original virus strain, the company said in a statement on Monday. CureVac's first mRNA-based COVID vaccine CVnCoV, showed the efficacy of just 47 per cent, the lowest reported so far from any COVID-19 vaccine maker.

The new study assessed cynomolgus macaques vaccinated with 12 micrograms of either the first or second-generation vaccine candidate. Better activation of innate and adaptive immune responses was achieved with CV2CoV, resulting in faster response onset, higher titers of antibodies, and stronger memory B and T cell activation as compared to the first-generation candidate, CVnCoV.

When tested against the original SARS-CoV-2 virus, it was found to be better protected based on highly effective clearance of the virus in the lungs and nasal passages, the company said. "In this model, CV2CoV is shown to induce broad antibody and cellular immune responses very similar to the breadth of the immune responses observed after infection with SARS-CoV-2," said Dr. Igor Splawski, Chief Scientific Officer of CureVac. The companies aim to roll out CV2CoV's Phase 1 clinical trial in Q4 2021.

The mRNA technology was a "strategic priority", said Rino Rappuoli, head of vaccines research and development at GSK. "The strong immune response and protection in pre-clinical testing of this second-generation mRNA backbone are very encouraging and represent an important milestone," he added.