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Preclinical Data on Intranasal COVID-19 Vaccine Shows Protection from SARS-CoV-2 after Single Dose

Meissa’s intranasal recombinant live attenuated COVID-19 vaccine, MV-014-212, induced mucosal as well as systemic antibodies against SARS-CoV-2 and two variants of concern

MV-014-212 was built on the company’s AttenuBlock platform and is designed to be appropriately attenuated, genetically stable, and optimized to drive robust, broad, and durable immunity

Data will be presented at American Society for Virology (ASV) 2021 and are available on bioRxiv

REDWOOD CITY, Calif., July 19, 2021 – Meissa Vaccines (“Meissa”), a biotechnology company developing vaccines to prevent serious viral respiratory infections, announced today the release of preclinical data in nonhuman primates (NHPs) of the company’s intranasal recombinant live attenuated COVID-19 vaccine (MV-014-212). The data demonstrate that a single adjuvant-free dose of MV-014-212 provided equivalent protection against SARS-CoV-2 challenge compared to reported efficacy in NHP models of currently authorized vaccines. Furthermore, the data show that MV-014-212 stimulates mucosal (nasal IgA) antibodies in the upper respiratory tract, the major infection route for SARS-CoV-2, and systemic (serum neutralizing and binding IgG) antibodies. Meissa also announced that the company has enrolled and dosed SARS-CoV-2 seronegative and seropositive adult participants in all dosage groups of a Phase 1 clinical trial of MV-014-212 ( identifier: NCT04798001). Interim analysis of the trial data is expected later this year.

“Many scientists and public health officials think SARS-CoV-2 is becoming endemic, and we believe Meissa’s intranasal COVID-19 vaccine can contribute to global control of the disease and virus spread,” said Martin Moore, Ph.D., CEO and Cofounder of Meissa Vaccines. “The data suggest a single, adjuvant-free, needle-free intranasal dose of MV-014-212 may provide broad immunity to protect against infection by SARS-CoV-2 and its variants.”

Injected vaccines are likely to curtail but not contain transmission, whereas a live attenuated intranasal vaccine has the greatest potential to block transmission, prevent infections, and provide broad and long-lasting immunity. The mucosal immune response is the first line of defense against respiratory viruses, providing fast-acting protection at the primary site of exposure. In NHPs, Meissa’s intranasal COVID-19 vaccine generated both mucosal and systemic antibodies and was highly protective against wild-type SARS-CoV-2 challenge. Serum antibodies were able to neutralize wild-type SARS-CoV-2, B.1.351 (Beta, South Africa), and B.1.1.7 (Alpha, UK). Additional data from serial passaging in manufacturing cell line and virus shed from NHPs showed that MV-014-212 has a stable genotype in vitro and in vivo.

We have deployed Meissa’s AttenuBlock platform to establish a recombinant live attenuated COVID-19 vaccine that is designed to be genetically stable as well as optimized to drive robust and durable immunity,” said Roderick Tang, Ph.D., Chief Scientific Officer and Cofounder of Meissa Vaccines. “We believe Meissa’s intranasal COVID-19 vaccine has the potential to be an important part of the endgame solution to contain SARS-CoV-2.”

Because coronaviruses are genetically unstable, a conventional live attenuated coronavirus vaccine strategy is not recommended for SARS-CoV-2. To overcome this challenge, MV-014-212 was built on the company’s AttenuBlock platform. This platform incorporates 10 years of research and development employing rational and precise codon deoptimization and other genetic strategies to produce a vaccine backbone that provides appropriate attenuation, genetic stability, and optimized immunity. In addition, live attenuated vaccines are effective at lower dosages and scalable with a straightforward and economical manufacturing process.

Dr. Moore concluded, “With AttenuBlock, a modernized live attenuated vaccine platform, we have the potential to not only deliver a protective COVID-19 vaccine, but also produce enough supply for the world with a relatively small manufacturing footprint. We believe Meissa’s intranasal COVID-19 vaccine could help us get rid of masks for good, get back to normal, and potentially immunize billions of people who don’t have access to currently authorized vaccines and who will need boosters periodically.”

Mariana Tioni, Ph.D., will present these data at ASV 2021 on July 22nd from 6-8 pm EDT. The data are also available on bioRxiv:

About Meissa Vaccines

Meissa Vaccines was founded with a mission to protect people everywhere from life threatening respiratory viruses and a commitment to develop innovative technologies capable of delivering effective vaccines at a global scale. Meissa is advancing live attenuated vaccine candidates against respiratory syncytial virus (RSV), SARS-CoV-2 (COVID-19), and human metapneumovirus (hMPV). These vaccine candidates have been developed using the company’s proprietary AttenuBlock synthetic biology platform, which includes codon deoptimization and technologies exclusively licensed from Emory University and Children’s Healthcare of Atlanta. Meissa’s live attenuated vaccine candidates are formulated to be delivered as a single, intranasal, adjuvant-free, needle-free dose and are designed to generate a strong, durable immune response to prevent infection and disease. Meissa is headquartered in Redwood City, Calif.

Meissa Contacts:

For Clinical Trials:

Corporate Contact: Bill Daly, Chief Business Officer, Meissa Vaccines,

For Media Only: Jessica Yingling, Ph.D., Little Dog Communications, +1.858.344.8091,


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