Immunotherapy with killed bacteria reduces mortality and boosts vaccines against COVID-19

An immunotherapy based on the intranasal administration of a preparation of killed bacteria (called MV130) is highly effective in preventing mortality caused by the coronavirus (SARS-CoV-2) and in enhancing the effect of vaccines against COVID-19.

It has been verified -for the moment in animals- by a team of Spanish scientists, who have shown with these results that the efficacy and immune response of vaccines can be improved, particularly in some segments of the population and also against variants of the pathogen that may reduce the effectiveness of these vaccines, and thus contribute to better protection of the population against the COVID-19.

The results of the investigation -which are published today in the journal Frontiers in Inmunology– have yielded strong scientific evidence: the mortality of infected mice was significantly lower when they received this immunotherapy (MV130) before infection.

Numerous centers have participated in the research, coordinated by researchers Carlos del Fresno, from the Health Research Institute of the La Paz University Hospital; Juan García Arriaza and Mariano Esteban, from the National Center for Biotechnology (CNB) of the Higher Council for Scientific Research (CSIC); and David Sancho, from National Center for Cardiovascular Research (CNIC).

The arrival of the vaccines has been the best weapon against pandemic, have underlined the CNIC and the CSIC in a note released today, but they have confirmed the need for effective and fast tools to respond to the appearance of new viruses, something that can be achieved by training the immune response.

And the immunotherapy composed of dead bacteria (called MV130), produced by the Spanish company Immunotek (Alcalá de Henares, Madrid), has demonstrated this efficacy in the experiments that have already been carried out at the Animal Health Research Center (CISA) of the National Institute of Agricultural and Food Research and Technology (INIA-CSIC), in Madrid.

David Sancho has explained to EFE that it is an investigational drug in Spain which has already been used in clinical trials with good results in recurrent respiratory infections in children and adults, and has ensured that it could be manufactured in sufficient quantities to be administered to risk groups, such as those over 70 years of age.

It would serve, the scientist explained, to strengthen innate immunity “If we face a new situation of a respiratory pathogen against which we do not have a specific vaccine, or to reinforce vaccines with limited efficacy, such as the flu”.

”Given the high efficacy of vaccines against COVID-19We believe that its application would be limited to those individuals who may have a lower response to vaccination “, has explained David sancho, and has assured that they already have data in mice – which they have not yet published – that show that this immunotherapy is effective against other viruses, so it could also be applied to other infections.

The CNIC and the CSIC have recalled that until a few years ago it was believed that specific (or adaptive) immunity was the only one that possessed memory (the ability to remember previous pathogens such as viruses or bacteria) and trigger the response to defend the organism, while innate immunity (not specific for a particular pathogen) did not have that ability.

“Today it is known that innate immunity can be trained to achieve a better response against subsequent unrelated infections; for example, training innate immunity with bacterial preparations to protect against viral infections, such as SARS-CoV-2, and that such training lasts over time “, according to David Sancho.

Researchers have studied whether this immunotherapy, applied prior to the administration of vaccines against COVID-19, could enhance the immune responses generated by those vaccines, and they have shown that it does.

“The result revealed that animals that received MV130 prior to vaccination and, therefore, had a trained innate immune system, showed better immune responses after vaccination”, has pointed out the scientist Carlos del Fresno.

In the same sense, the researcher Juan García Arriaza has asserted that immunotherapy with this “preparation” protects directly against mortality from the coronavirus SARS-CoV-2 and helps improve immune responses generated by vaccines.

“These are relevant results that indicate that, in the case of future new infections caused by emerging pathogens, immunotherapy with MV130 could protect groups particularly sensitive to the pathogen until the arrival of specific vaccines against antigens associated with the pathogen”, Mariano Esteban has pointed out.