Single-Dose 13-Valent Conjugate Pneumococcal Vaccine in People Living With HIV - Immunological Response and Protection.

Background: Patients living with HIV (PLHIV) are prone to invasive pneumococcal disease. The 13-valent conjugated pneumococcal vaccine (PCV13) is currently recommended for all PLHIV, followed in most guidelines by a 23-valent polysaccharide pneumococcal vaccine. Data are scarce concerning the immunological efficacy of PCV13 among PLHIV.

Objective: To assess the immunological response at one month, and the immunological protection at 1-, 6-, and 12 months in PLHIV with a CD4 cell count above 200 cells/µl after a single dose of PCV13, as measured by both ELISA and opsonophagocytic assay (OPA).

Methods: PLHIV with CD4 cell count >200 cells/µl were included. Specific IgG serum concentrations for eight serotypes by ELISA and seven serotypes by OPA were measured at baseline, 1-, 6-, and 12 months after the PCV13 vaccination. Global response was defined as a two-fold increase from baseline of specific IgG antibody levels (μg/ml) assayed by ELISA or as a four-fold increase in OPA titer from baseline, for at least five serotypes targeted by PCV13. Global protection was defined as an IgG-concentration ≥1 µg/ml by ELISA or as an opsonization titer ≥LLOQ by OPA for at least five tested serotypes targeted by PCV13. Factors associated with global response and global protection were assessed using logistic regression.

Results: Of the 38 PLHIV included, 57.9% and 63.2% were global responders, 92.1% and 78.9% were globally protected at one month, and 64.7% and 55.9% were still protected at 12 months, by ELISA and OPA respectively. A CD4/CD8 ratio of >0.8 was significantly associated with a better global response by OPA (OR=6.11, p=0.02), and a CD4 nadir <200 was significantly associated with a poorer global response by ELISA (OR=0.22, p=0.04). A CD4 cell count nadir <200 and age over 50 years were associated with poorer global protection by OPA at M1 (OR=0.18, p=0.04) and M12 (OR= 0.15, p=0.02), respectively. Plasma HIV RNA viral load <40 copies/ml was significantly associated with a better global protection at M1 by ELISA and OPA (OR=21.33, p=0.025 and OR=8.40, p=0.04).

Conclusion: Vaccination with PCV13 in these patients induced immunological response and protection at one month. At one year, more than half of patients were still immunologically protected.