The Moderna vaccine shows strong prevention of SARS-CoV-2 infection in an animal model

Coronavirus 2019 pandemic (COVID-19) is spreading worldwide. Vaccination efforts against its causative agent – the acute acute coronavirus 2 (SARS-CoV-2) respiratory syndrome – have begun in many parts of the world.

One of the currently being released vaccines is the mRNA-1273 (or Moderna) COVID-19 vaccine. U.S.-based researchers have demonstrated that the primary or primary stimulant mRNA-1273 vaccine in hamsters induced strong neutral antibodies, reduced weight loss, and reproduced SARS-CoV-2 induced down in the airways.

The team – from the Medical Branch of the University of Texas, Princeton University, Icahn School of Medicine at Mount Sinai, and Moderna Inc. – on their conclusions about the bioRxiv* server.

Moderna COVID-19 vaccine

The Moderna COVID-19 vaccine, also known as mRNA-1273, is a nanoparticle-encapsulated mRNA-based lipid vaccine that encodes the stable full-length spike protein of SARS-CoV-2. In short, it allows the host to develop neutralizing antibodies against the virus’s spike protein antigen, which effectively prevents SARS-CoV-2 viruses from invading and infecting. into cells if the guest appears.

Manufactured by ModernaTX, Inc., the vaccine is intended to prevent COVID-19 in people over 18 years of age.

The study

The study showed that administration of a primary stimulant of mRNA-1273 generated a strong anti-neutral antibody response and inhibited the reproduction of the virus in the airways.

Although the vaccine has been used in human trials, these cannot provide a controlled response to diseases and complex immunological vision that can only be performed by preclinical studies. Hamsters are the only model that can cause more severe SARS-CoV-2 infection, similar to hospitalized patients. This makes hamsters relevant for vaccine evaluation.

To reach the conclusions of the study, the researchers tested the efficacy of the Moderna vaccine with only primary levels and three doses of primary stimulant regimens using the Syrian hamster hard model. They conducted a series of tests and studies to identify intermediate vaccines before and after the challenge.

The team has found that hamsters vaccinated with the mRNA-1273 vaccine stimulated strong neutral antibody responses, suppressed the immune-mediated immune cells, and the reductions in white blood cells in the lungs .

Three groups of hamsters were vaccinated with 25 µg, 5 µg, and 1 µg of mRNA-1273 in a primary stimulation regimen. One group received the primary dose of 25 µg at week 0 and another group receives placebo vaccines. The team monitored and quantified the humoral responses to a vaccine with an enzyme-linked immunosorbent assay (ELISA) specific for the protein in SARS-CoV-2 and its receptor binding domain (RBD).

Three weeks after the main dose was administered, higher S-specific immunoglobulin G (IgG) titers were observed in the hamsters who received the 25 µg and 5 µg doses compared to the 1 µg dose. Further, S-specific IgG titles were significantly increased in all groups following the increase. However, the 25 µg and 5 µg dose groups had higher S-specific IgG titers.

Overall, the study showed that two doses of mRNA-1273 vaccine reduced viral loads in the upper and lower airways of hamsters, protecting them against weight loss. Primary immunization provided only partial protection. Simultaneously, two doses of mRNA-1273 are required to induce neutral titers similar to the higher titers seen in COVID-19 convalescent patients.

The most effective dosage was 25 µg, which provided better protection against lung injury and weight loss.

MRNA-1273 showed that protection is mainly achieved through the induction of antibodies, and cellular responses may support complete clearance of the virus. Importantly, the safety of mRNA-1273 was indicated by the absence of unstable cellular pathways in VI hamsters after challenge, ”the researchers in the study concluded.

The team urged further studies to examine how immunity to other vaccines is regulated after infection to provide a basis for a better vaccination campaign.

* Important message

bioRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or be treated as information established.