sa-mRNA COVID-19 Vaccine Candidate Demonstrated Longer Duration of Immunity

CSL and Arcturus Therapeutics today announced the results of a follow-up analysis of a Phase 3 study evaluating a booster dose of ARCT-154, the world's first approved self-amplifying messenger RNA (sa-mRNA) COVID-19 vaccine, compared to a conventional mRNA COVID-19 vaccine.

The new analysis at six months post-vaccination shows that ARCT-154 induces a longer immune response than Comirnaty® for both the original Wuhan strain and Omicron BA.4/5 variant and an advantage in antibody persistence.

ARCT-154 was administered at one-sixth the dose of Comirnaty® (5 μg vs 30 μg, respectively).

"These results further support sa-mRNA's differentiating attribute to provide prolonged protection against COVID-19 at lower doses," said Jonathan Edelman, M.D., Senior Vice President, Vaccines Innovation Unit, CSL, in a press release on February 5, 2024.

"Protecting the global public from viral respiratory diseases remains a top priority for us, and we look forward to continuing to collect and share data at the twelve-month post-booster mark."

Unlike standard mRNA vaccines, these companies commented that self-amplifying mRNA vaccines instruct the body to make more mRNA and protein to boost the immune response.