Effects of Probiotic Mixture Supplementation on the Immune Response to the 13-Valent Pneumococcal Conjugate Vaccine in People Living with HIV.

Background: In people living with HIV, combination antiretroviral therapy (cART) reduces the risk of death, but the persistent immune-deficient state predisposes them to pneumococcal infections. Current guidelines encourage administering pneumococcal vaccine Prevenar 13 to patients living with HIV. Since probiotic supplementation could act as adjuvants and improve vaccine immunogenicity by modulating gut microbiota, the present study aimed to assess whether the effect of a formulation containing a combination of specific probiotics (Vivomixx) could improve the immune response to 13-valent pneumococcal conjugate vaccine (PCV13) in adult people living with HIV.

Methods: Thirty patients who were clinically stable and virologically suppressed, without opportunistic infections during this time and no ART changes in the 12 months before the study started were enrolled. Patients were divided into two groups: (1) received a placebo dose and (2) received Vivomixx (1800 billion CFU) for four weeks before and after the vaccination with a single dose of PCV13.

Results: Vivomixx supplementation induced a better response to PCV13 immunization, as shown by greater change in anti-Pn CPS13 IgG and increase in salivary IgA, IL-10 and IL-8.

Conclusions: Additional investigations will help to clearly and fully elucidate the optimal strains, doses, and timing of administration of probiotics to improve protection upon vaccination in immunocompromised individuals and the elderly.