Pneumococcal 21-Valent Vaccine Well-Tolerated, Immunogenic in Patients Living With HIV

V116, an adult-specific, pneumococcal 21-valent conjugate vaccine (PCV21, Capvaxive; Merck), was found to be well-tolerated and immunogenic for all 21 serotypes in adults living with HIV who present at high risk of severe pneumococcal disease, according to results from the 2-part, parallel-group, randomized, active comparator-controlled, international, phase 3 STRIDE-7 (NCT05393037) clinical trial published by investigators in The Lancet HIV.^1,2

Elucidating the Efficacy and Safety of PCV21

The STRIDE family of trials has thoroughly investigated PCV21 in numerous settings and populations to flesh out its safety and effectiveness at preventing pneumococcal disease. In STRIDE-9, V116 demonstrated robust immunogenicity compared with the 23-valent pneumococcal polysaccharide vaccine (PPSV23; Pneumovax) in older adults who were naïve to pneumococcal vaccination. Meanwhile, STRIDE 4 demonstrated the consistent efficacy and safety of V116 across manufacturing lost. Most recently, investigators from STRIDE-13 found that V116 demonstrated comparable efficacy to PPSV23 in high-risk children and adolescents.^3-5

Determining the efficacy of V116 in individuals at high risk for pneumococcal disease is especially important. People living with HIV (PLWH) are particularly susceptible to the development of severe disease, even when receiving combination antiretroviral therapy, due to incomplete recovery of anti-pneumococcal host defenses and widespread immunosuppression. Therefore, it is critical to evaluate the feasibility of PCV21 vaccination in this population.^1,6

Methods of STRIDE-7

Thus, the STRIDE-7 trial was initiated. The 2-part trial was conducted across 20 facilities in the US, Belgium, France, and South Africa, among others. In part A, which was a randomized, active comparator-controlled, parallel-group, multicenter, double-blind in PLWH aged 18 or older, patients were randomly assigned to receive V116 followed by placebo 8 weeks later or 15-valent PCV (PCV15) followed by PPSV23 8 weeks later. The primary outcome of this part was serotype-specific opsonophagocytic activity geometric mean titers 30-days post-vaccination. Part B, which was exploratory, was an open-label trial of PCV15 following receipt of V116 in part A.¹

A total of 313 participants were randomly assigned—156 in the V116 plus placebo group and 157 in the PCV15 plus PPSV23 group—and 304 (97%) ultimately completed part A (152 in each group). Additionally, 126 (81%) of 155 participants in the V116 plus placebo group as-treated population from part A received PCV15 in part B, with a median administration interval of 11.4 months.¹

Robust Immunogenicity Observed in People Living With HIV

V116 was found to demonstrate immunogenicity for all 21 Streptococcus pneumoniae serotypes contained in the vaccine. Furthermore, immune responses at day 30 were comparable to those in individuals vaccinated with PCV15 plus PPSV23 at week 12 for the 13 common serotypes, and even higher responses for the 8 serotypes unique to V116.

These indications show that, in an immunocompromised population, V116 can provide significant protection against pneumococcal disease, especially for serotypes that were most recently added to the vaccine’s formulation.¹

Positive indicators from this trial continued into the realm of safety. The authors observed that, in part A, fewer participants had at least 1 adverse event (AE) in the V116 plus placebo group (111 of 152 [72%]) compared with the PCV15 plus PPSV23 group (141 of 155 [91%]). There was also a lower frequency of injection-site AEs (79 [51%] vs 130 [84%]), a critical component of vaccination for PLWH given their immunocompromised state. In a critical measure, there was an extremely low rate of serious AEs (4 [3%] in the V116 plus placebo group vs 6 [4%] in the PCV15 plus PPSV23 group), and none were deemed to be vaccine related.¹

These results provide important insights to health care providers and pharmacists. PLWH are at an increased risk for numerous diseases, including respiratory conditions such as pneumococcal disease. Given their immunocompromised state, providing robust protection in the form of vaccination to these individuals is of paramount importance.

With V116 able to protect against more prevalent strains of Streptococcus pneumoniae compared with its predecessors, it is poised to become a critical tool in protecting PLWH from serious infections.¹

REFERENCES

1. Pathirana J, Ramgopal M, Martin C, et al. Safety, tolerability, and immunogenicity of an adult-specific pneumococcal conjugate vaccine, V116, in people living with HIV (STRIDE-7): a two-part, parallel-group, randomised, active comparator-controlled, international, phase 3 trial. The Lancet HIV. 2025. doi:10.1016/S2352-3018(25)00165-1

2. Safety and Immunogenicity of V116 in Adults Living With Human Immunodeifiency Virus (HIV) (V116-007, STRIDE-7). ClinicalTrials.gov Identifier: NCT05393037. Last Updated March 30, 2025. Accessed September 17, 2025. https://clinicaltrials.gov/study/NCT05393037

3. Halpern L. V116 Well Tolerated With Broad Immune Responses in Pneumococcal Vaccine-Naive Older Adults. Pharmacy Times. Published August 12, 2025. Accessed September 17, 2025. https://www.pharmacytimes.com/view/v116-well-tolerated-with-broad-immune-responses-in-pneumococcal-vaccine-na-ve-older-adults

4. Halpern L. 21-Valent Pneumococcal Conjugate Vaccine Exhibits Consistent Safety and Immunogenicity Across Manufacturing Lots. Pharmacy Times. Published June 30, 2025. Accessed September 17, 2025. https://www.pharmacytimes.com/view/21-valent-pneumococcal-conjugate-vaccine-exhibits-consistent-safety-and-immunogenicity-across-manufacturing-lots

5. Halpern L. PCV21 Effective in Children, Adolescents at Increased Pneumococcal Disease Risk. Pharmacy Times. Published September 13, 2025. Accessed September 17, 2025. https://www.pharmacytimes.com/view/pcv21-effective-in-children-adolescents-at-increased-pneumococcal-disease-risk

6. Feldman C, Anderson R, Rossouw T, et al. HIV-related pneumococcal disease prevention in adults. Expert Rev Respir Med. 2017;11(3):181-199. doi:10.1080/17476348.2017.1289841