Study suggests inactivated bacteria could help prevent COVID-19

OVIEDO, Spain

A group of Spanish researchers found that treating mice with inactivated bacteria before giving them COVID-19 reduced mortality from 60% to 25%, said a study published on Thursday.

Giving mice a mucosal immunotherapy composed of the bacteria before a COVID-19 vaccine also further increased immune responses and made the vaccine significantly more effective, suggested the data, published in the prestigious journal Frontiers in Immunology.

Unlike COVID-19 vaccines, which activate the adaptive immune system, this treatment "trained" the mice's innate immune system to go after viruses more effectively.

The innate immune system is the body's first line of defense against unwanted pathogens. It does not create specific antibodies for each virus but instead broadly springs into action whenever challenged.

The same bacteria, called MV130, has already been shown to be clinically effective at preventing recurrent wheezing in children that was mostly triggered by other viruses. In the same trial, the results of which were published in August, data suggested that the treatment also enhanced immune responses against influenza viruses.

"Our results indicate that mucosal immunotherapy with MV130 represents a promising new tool to fight the tremendous global challenge represented by new emerging viruses, exemplified by SARS-CoV-2," said the peer-reviewed study.