Moderna’s vaccine shows protection from COVID-19 in monkey study

US biotechlogy company Moderna's experimental vaccine to prevent COVID-19 induced robust immune responses and rapidly controlled vel coronavirus in upper and lower airways of monkeys exposed to SARS-CoV-2, according to a study.

candidate vaccine, mRNA-1273, has been co-developed by scientists at Moderna and National Institute of Allergy and Infectious Diseases (NIAID) in US. study, published in New England Journal of Medicine, complements recently reported interim results from an NIAID-sponsored Phase 1 clinical trial of mRNA-1273.

In study, three groups of eight rhesus macaques received two injections of 10 or 100 microgrammes (μg) of mRNA-1273 or a placebo. Injections were d 28 days apart. Vaccinated macaques produced high levels of neutralising antibodies directed at surface spike protein used by SARS-CoV-2 to attach to and enter cells, researchers said.

Animals receiving 10-μg or 100-μg dose vaccine candidate produced neutralising antibodies in blood at levels well above those found in people who recovered from COVID-19, y said. researchers said experimental vaccine also induced Th1 T-cell responses but t Th2 responses.

Induction of Th2 responses has been associated with a phemen called vaccine-associated enhancement of respiratory disease (VAERD), y said. According to researchers, vaccine-induced Th1 responses have t been associated with VAERD or or respiratory diseases.

experimental vaccine also induced T follicular helper T-cell responses that may have contributed to robust antibody response, y said. Four weeks after second injection, all macaques were exposed to SARS-CoV-2 via both se and lungs, according to study.

It found that after two days, replicating virus was detectable in lungs of seven out of eight of macaques in both vaccinated groups, while all eight placebo-injected animals continued to have to replicate virus in lung. ne of eight macaques vaccinated with 100 μg of mRNA-1273 h detectable virus in ir ses two days after virus exposure, researchers said.

This is first time an experimental COVID-19 vaccine tested in nhuman primates has been shown to produce such rapid viral control in upper airway, researchers ted. A COVID-19 vaccine that reduces viral replication in lungs would limit disease in individual while reducing shedding in upper airway would potentially lessen transmission of SARS-CoV-2 and consequently reduce spre of disease, y ded.

(Photo credits: AP)