Meissa Vaccines has reported that its intranasal Covid-19 vaccine, MV-014-212, generated a robust nasal Immunoglobulin A (IgA) antibody response in seropositive and seronegative adults in Phase I clinical trial.

The live attenuated vaccine is built on the recombinant respiratory syncytial virus (RSV) AttenuBlock platform of Meissa.

It has been designed to be well-attenuated, genetically stable and optimised to offer strong and long-lasting immunity.

The latest initial results are from an interim analysis conducted on 49 subjects.

Of the doses ranging from 10^3-10^5 PFU analysed in the trial, the 10^5 PFU dose stimulated nasal IgA antibody levels that were in line with natural immunity to Covid-19 infection.

The safety data at all the tested dose levels of the vaccine showed MV-014-212 is greatly attenuated, without any infectious vaccine virus seen in trial subjects.

Furthermore, no serious adverse events linked to the vaccine were observed so far.

Currently, the Phase I trial is underway enrolling subjects with full data anticipated next year.

Meissa Vaccines chief medical officer Robert Walker said: “The preliminary clinical data indicate a single, adjuvant-free, needle-free dose of Meissa’s Covid-19 intranasal vaccine can stimulate a nasal IgA antibody response similar to that seen after SARS-CoV-2 infection, with an important difference – safety.

“We will continue to advance Meissa’s Covid-19 intranasal vaccine in this Phase I clinical trial in adults, and we plan to evaluate it as a booster to complement injectable vaccines and initiate a Phase I paediatric study next year.”

The vaccine induced both mucosal and systemic antibodies and demonstrated greater protection against wild-type SARS-CoV-2 challenge in nonhuman primates in preclinical studies.

In addition, serum antibodies were found to neutralise wild-type SARS-CoV-2, as well as the Beta and Alpha variants of the virus.