TIMELINE AND EFFICIENCY

• The mass production of this vaccine is much easier than it has been for vaccines in the past i Manufacture and delivery of clinical trials material was completed in 45 days, and the first trial vaccines were given 66 days after the genomic sequence of the virus was released

SAFETY PROFILE

• The two-dose vaccine series was completed without serious toxicity, and adverse effects were mild or moderate for the most part.
• Local injection-site reactions were mild, similar to other mRNA vaccines that were investigated.

PERFORMANCE OF THE VACCINE

• The mRNA-1273 vaccine was immunogenic, meaning it was successful in inducing robust binding antibody responses.
• Seroconversion was rapid for binding antibodies, and was seen within 2 weeks after the first vaccination.
• Pseudovirus neutralizing activity was low before the second vaccination -> supports the need for a second vaccination
• Measurements of serum neutralizing activity were similar to mechanisms seen in protecting for other respiratory viruses, like influenza.
• In phase 3, efficacy trials will allow assessment of the correlation of vaccine-induced immune responses with clinical protection.
• Durability of immune response will be tested in 1 year.
• The speed and efficiency of mRNA-1273 probably comes from an innovative antigen design, coupled with a potent lipid-nanoparticle delivery, alongside the use of modified nucleotides to avoid early intracellular activation of interferon-associated genes. These features lead to prolonged protein expression, induction of antigen-specific T-follucular helper cells, and activation of germinal center B cells
• Previous animal trials have raised concern about vaccine-associated enhanced respiratory disease. Evidence suggests this won't happen in humans and that it is safe to proceed.