Pneumococcal Vaccines Show Moderate Immunogenicity, Strong Safety in Children With Cancer

Pneumococcal vaccines produced moderate immune responses and were well tolerated in children with cancer, but protection was weaker during active chemotherapy and faded within a year after treatment, according to a systematic review and meta-analysis presented at IDWeek 2026 in Washington, DC.¹

Children with cancer face a 20- to 100-fold higher risk of invasive pneumococcal disease (IPD) than other children because of immunosuppression from both malignancy and chemotherapy. In a Brazilian pediatric oncology cohort, IPD incidence reached about 311.21 cases per 100,000 patient-years, with a mortality rate of 7.8%. Severe neutropenia was the only independent risk factor identified. The CDC recommends risk-based pneumococcal vaccination for children with immunocompromising conditions, including leukemia, lymphoma, and other malignancies, but optimal timing relative to chemotherapy remains unclear.^1-3

Review Included 18 Studies and 2847 Children

Investigators from Tata Memorial Hospital in Mumbai, India, followed PRISMA 2020 guidelines to search PubMed, SciSpace, and Google Scholar for studies published from 2016 to 2026 evaluating PCV7, PCV10, PCV13, PCV15, PCV20, or PPSV23 in children aged 0 to 18 years with cancer. Of 927 records, 18 studies met inclusion criteria, and 12 were included in the meta-analysis. The studies involved 2847 children, most of whom had leukemia (68%), followed by solid tumors (22%) and lymphoma (10%).¹

Responses Were Stronger After Chemotherapy but Waned

Pooled PCV13 seroprotection was approximately 76% (95% CI, 55%-90%) when the vaccine was given after chemotherapy, compared with 47% (95% CI, 15%-80%) during active treatment (P < .001). By 12 months after chemotherapy, seroprotection had dropped to 40% (95% CI, 25%-55%). Children with acute lymphoblastic leukemia (ALL) responded similarly to those with other cancer types, whereas hematopoietic stem cell transplant (HSCT) recipients required 3 to 4 doses for adequate protection.¹

Serious adverse events occurred in 2.8% of children (95% CI, 1.0%-5.3%), with no vaccine-related deaths; however, none of the included studies reported IPD incidence, and data on PCV15 and PCV20 were limited.¹

Authors Recommend a 2-Dose Strategy

The investigators recommend vaccination during maintenance chemotherapy, followed by a booster 4 to 12 months after treatment ends. Earlier research supports this approach. In a study of 71 children with ALL, approximately 53.1% of those who received PCV13 during maintenance were seroprotected at the end of chemotherapy, compared with 25.6% of those who did not. After a postchemotherapy booster, rates rose to 96.9% and 100%, respectively.^1,4

“Although antibody responses are generally stronger after chemotherapy, delaying vaccination leaves children unprotected during a period of substantial infection risk,” Gaurav Vijay Salunke, MBBS, MD, professor at Tata Memorial Hospital, said in an interview with Pharmacy Times. “Starting during maintenance therapy provides earlier, potentially partial protection, followed by a posttreatment dose or booster when immune recovery is better.”

Salunke added that timing should be individualized based on chemotherapy intensity, lymphocyte recovery, prior vaccination, and local guidance.

Pharmacists Can Support Vaccine Completion

According to Salunke, pharmacists can reconcile immunization records, identify missed doses, coordinate timing with oncology appointments, educate families about expected reactions, and track completion across oncology, primary care, and transplant services.

“Direct pharmacist-specific evidence in pediatric oncology is limited, so these should be viewed as practical multidisciplinary strategies rather than proven outcome interventions,” Salunke said.

HSCT Recipients Need Tailored Revaccination

Salunke explained that HSCT recipients may lose pretransplant immune memory and experience delayed B-cell and T-cell reconstitution, and that graft-versus-host disease and immunosuppressive drugs can further blunt responses.

“Repeated conjugate-vaccine doses are used to prime and strengthen responses,” Salunke added. “The exact schedule should not be assumed to be identical for every patient.”

Care teams should base timing on immune recovery and transplant guidance, account for ongoing immunosuppression, and document every dose, according to the authors.

Clinical Effectiveness Data Are Needed

Because effectiveness data are lacking, the authors said vaccination should be paired with prompt evaluation of fever or respiratory symptoms, rapid treatment of suspected bacterial infection, and review of household vaccination.

“Clinicians should also review household vaccination and avoid assuming that an adequate antibody response guarantees lifelong protection. Revaccination or booster decisions should follow oncology/transplant protocols and immune recovery rather than antibody decline alone. Clinicians should also review household vaccination and avoid assuming that an adequate antibody response guarantees lifelong protection. Revaccination or booster decisions should follow oncology/transplant protocols and immune recovery rather than antibody decline alone,” Salunke said.

They identified prospective studies measuring IPD, pneumonia, serotype-specific breakthrough infections, and vaccine effectiveness by treatment phase as research priorities, along with studies comparing schedules and evaluating pharmacist-led adherence interventions.

REFERENCES

1. Salunke G, Samant P, Biswas S. Immunogenicity, effectiveness, and safety of pneumococcal vaccination in children with cancer: a systematic review and meta-analysis. Poster P-1141 presented at: IDWeek 2026; October 21-24, 2026; Washington, DC.

2. Lages PM, Carlesse F, Boettger BC, Pignatari ACC, Petrilli AS, de Moraes-Pinto MI. Invasive pneumococcal disease in children with cancer: incidence density, risk factors and isolated serotypes. Braz J Infect Dis. 2020;24(6):489-496. doi:10.1016/j.bjid.2020.09.003

3. CDC. Summary of risk-based pneumococcal vaccination recommendations. Updated May 8, 2026. Accessed November 13, 2026. https://www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/risk-indications.html

4. Dorval S, Gantt S, Leclerc JM, et al. Pneumococcal vaccination during chemotherapy in children treated for acute lymphoblastic leukemia. Pediatr Blood Cancer. 2021;68(6):e28944. doi:10.1002/pbc.28944