GX-19

• mRNA vaccines like Pfizer-BioNTech's BNT162b2 and Moderna's mRNA-1273 have demonstrated high efficacy (72-95%) against moderate-to-severe COVID-19 in adults, with ongoing studies evaluating their effectiveness against emerging variants. • DNA vaccines, including Zydus Cadila's ZyCov-D, have shown promise with good safety profiles and the ability to induce neutralizing antibodies and cellular immune responses, offering a cost-effective alternative, especially in developing countries. • Studies indicate that extending the interval between doses of mRNA vaccines may enhance immune responses, particularly in previously uninfected individuals, although the recognition of variants like Omicron may decline more rapidly. • Booster doses of mRNA vaccines, such as BNT162b2, have been shown to significantly improve neutralizing titers against Omicron variants, supporting a three-dose regimen for enhanced protection.

COVID-19 Vaccine Landscape: mRNA and DNA Vaccine Efficacy and Development

Drug Development Updates