Pneumococcal Conjugate Vaccines Reduces Incidence of Pneumonia for Children 2 Years and Under

Pneumococcal conjugate vaccines (PCV) reduced the incidence of pneumonia and improved levels of IgG antibodies in pediatric patients, according to results of a study published in Frontiers in Pediatrics. However, there is a lack of data on adverse events in children, so investigators stated that safety outcomes have to be explored more in future randomized controlled trials.¹

“Pneumococcal infections are the leading cause of childhood morbidity and mortality, especially in developing countries,” the study authors said.¹ “PCV, as an important component of the global childhood immunization program, has been widely recognized for its efficacy in preventing IPD [invasive pneumococcal disease] in children.”

The CDC currently recommends pneumococcal vaccination for children younger than 5 years old, as well as children with certain risk factors for severe disease. There are 2 types of vaccines recommended: PCVs, such as PCV15 and PCV20, and pneumococcal polysaccharide vaccine 23. For children under 5, they should receive 4 doses total, with one at 2 months, 4 months, 6 months, and 12 through 15 months.²

Pneumococcal infection is a growing concern for pediatric patients, according to a review in Cureus. The infection is associated with morbidity and mortality, especially for patients under 2 years. More severe and invasive diseases affect children with immunodeficiencies, malnutrition, chronic lung disease, and nephrotic syndrome, according to the authors. Symptoms can vary depending on the severity of infections.³

In the current study, the investigators aimed to gather the current data on the effect of PCV for children, which included protective efficacy or effectiveness against invasive disease, pneumonia, and otitis media, immunogenicity profiles, and safety parameters. The authors searched PubMed, Web of Science, Cochrane Library, and Embase up to June 19, 2024, and included studies in English. Studies included children who were aged 0 to 2 years, PCV and placebo vaccination, incidence of pneumonia, immunogenicity, safety, and a randomized controlled design.¹

Investigators identified 5678 studies but included 11 that met the eligibility criteria. All studies were published from 1998 to 2023 and included 147,274 patients aged 0 to 2 years, with 73,676 in the PCV group and 73,598 in the placebo group. Patients were from South Africa, Gambia, the Philippines, China, and Australia. The overall bias of the studies was low, but the investigators stated that the results still require careful consideration. Pneumonia was reported in 5 studies and included 141,979 patients. In the pooled analysis, the incidence of pneumonia was lower in the PCV group compared with the placebo. They also found that PCV9 significantly reduced the incidence of pneumonia, but the effects of PCV11 had no difference from the placebo, according to the study authors.¹

For immunogenicity, investigators found that PCV significantly elevated antibody 1, antibody 4, antibody 5, antibody 6B, antibody 9V, antibody 14, antibody 18C, antibody 19F, and antibody 23F compared with the placebo. For the safety analysis, all 11 studies were included, but most did not report specific adverse effects or adverse reactions, according to the study authors. In one study, the authors mentioned an increased incidence of asthma following immunization with PCV, and another showed a favorable safety profile for the vaccine.¹

“These findings are important for understanding the long-term protection of vaccines, optimizing vaccination strategies, and developing future vaccination policies,” the study authors said.¹ “We expect that this study will offer a scientific basis for public health decision-makers and clinical practice, and more comprehensive protection for children.”

READ MORE: Pneumococcal Resource Center

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REFERENCES

1. Dai Q, Dong Y, Wu J, Peng Q. Efficacy, immunogenicity, and safety of pneumococcal conjugate vaccine in children: a systematic review and meta-analysis. Front Pediatr. 2025;13:1652946. Published 2025 Oct 1. doi:10.3389/fped.2025.1652946

2. CDC. Recommended vaccines for children. June 26, 2024. Accessed October 24, 2025. https://www.cdc.gov/pneumococcal/vaccines/children.html

3. Thadchanamoorthy V, Dayasiri K. Review on Pneumococcal Infection in Children. Cureus. 2021;13(5):e14913. Published 2021 May 9. doi:10.7759/cureus.14913