Effects of Loigolactobacillus coryniformis K8 CECT 5711 on the Immune Response of Elderly Subjects to COVID-19 Vaccination: A Randomized Controlled Trial

Abstract

Elderly people are particularly vulnerable to COVID-19, with a high risk of developing severe disease and a reduced immune response to the COVID-19 vaccine. A randomized, placebo-controlled, double-blind trial to assess the effect of the consumption of the probiotic Loigolactobacillus coryniformis K8 CECT 5711 on the immune response generated by the COVID-19 vaccine in an elderly population was performed. Two hundred nursing home residents >60 yrs that had not COVID-19 were randomized to receive L. coryniformis K8 or a placebo daily for 3 months. All volunteers received a complete vaccination schedule of a mRNA vaccine, starting the intervention ten days after the first dose. Specific IgG and IgA antibody levels were analyzed 56 days after the end of the immunization process. No differences between the groups were observed in the antibody levels. During the intervention, 19 subjects had COVID-19 (11 receiving K8 vs. 8 receiving placebo, p = 0.457). Subgroup analysis in these patients showed that levels of IgG were significantly higher in those receiving K8 compared to placebo (p = 0.038). Among subjects >85 yrs that did not get COVID-19, administration of K8 tended to increase the IgA levels (p = 0.082). The administration of K8 may enhance the specific immune response against COVID-19 and may improve the COVID-19 vaccine-specific responses in elderly populations.

Evaluation of the effect of Loigolactobacillus coryniformis K8 CECT 5711 consumption in health care workers exposed to COVID-19

“…Several randomized clinical trials have shown the immunomodulatory activity of the probiotic strain L. coryniformis K8 ( 12 – 14 ) and support the working hypothesis. Indeed, in one of the studies performed in the context of influenza vaccination, it was observed that the incidence of local symptoms associated with respiratory infections (cough, sore throat, and nasal congestion) was 48% lower in the group that received the probiotic strain compared to the control group in a follow-up period of 6 months ( 13 ).…”

“…The placebo group received a daily capsule containing 220 mg of maltodextrin, whereas the probiotic group received a daily capsule containing 3 × 10 9 colony forming units of the L. coryniformis K8 strain in a matrix of the same maltodextrin combination in a quantity to achieve the same capsule weight (220 mg). This dose has been proven to be effective and safe in previous studies performed in adult population ( 12 – 14 ). The probiotic and placebo were packed in similar gelatin capsules in plastic containers, with just the randomization code distinguishing them.…”

“…Therefore, several authors have called for action to develop effective therapies and preventive measures to reduce infection and flatten the COVID-19 curve, and, in this context, probiotics could have a role ( 5 ). Our research group recently showed the usefulness of the probiotic L. coryniformis K8 in enhancing the immunological response of elderly people in the context of the COVID-19 vaccination ( 14 ). In the present study, we corroborated the role of L. coryniformis K8 as an adjuvant for boosting immunity by helping to extend the immune protection over time after COVID-19 vaccination in a group of HCWs.…”

“…This finding is in line with the results obtained in our previous study performed with vaccinated nursing home residents. In the subset of volunteers who were diagnosed with COVID-19 during the intervention, those who took L. coryniformis K8 had greater IgG-specific levels than those who took the placebo ( 14 ). Although the possible mechanisms involved in the activation of IgG production must be elucidated, the obtained results may have important clinical applications, since some studies found an association between RBD-IgG levels and protection against SARS-CoV-2 in different populations ( 24 , 25 ).…”

“…Additionally, in another trial carried out in elderly participants, L. coryniformis K8 increased the immunological response to influenza vaccination and reduced the symptoms associated with respiratory infections ( 13 ). Very recently, a randomized clinical trial performed in COVID-vaccinated nursing home residents, evidenced the usefulness of L. coryniformis K8 in the context of the COVID-19 pandemic by increasing the specific immune response after infection with COVID-19 and by helping the vaccine-specific responses in the elderly ( 14 ).…”