The working hypothesis is that the administration of a Lactobacillus strain improves the immune response in the elderly population, improving the immune response to a possible COVID-19 infection. The strain would act as an adjuvant that contributes to developing an effective response against the virus, and therefore there are fewer infectious symptoms due to this virus or, if it appears, it occurs in a milder way among the subjects who take the probiotic strain. Also,the investigators hypothesizes that the administration of the Lactobacillus may improve the immune response generated by the Covid-19 vaccine in this elderly population.
