According to CDC estimates, the U.S. 2022/23 influenza season resulted in an estimated 14 million flu-related medical visits, 360,000 flu-related hospitalizations, and 21,000 flu deaths—more than any season since before the COVID-19 pandemic.1 While influenza can impact anyone, some people are more at risk than others. Children aged 6 months and older, for example, are frequently in environments—such as schools and daycare centers—where the transmission may be especially high.2 Vaccination for all eligible individuals, especially vulnerable populations such as those aged younger than 5 years, is critical to helping protect individuals and communities from seasonal influenza.3

Recent analyses have examined real-world evidence about the benefits of different types of influenza vaccines. In a targeted literature review, researchers evaluated the vaccine effectiveness and efficacy (VE) and cost-effectiveness of a cell-based quadrivalent influenza vaccine (QIVc) in preventing influenza-related outcomes in the pediatric population.4 Searches of original research of QIVc and egg-based influenza vaccine (QIVe) identified 16 peer-reviewed clinical studies evaluating the VE of QIVc against influenza-like illness, cases, hospitalizations, or mortality in children and adolescents. These clinical studies found that influenza vaccination was effective in preventing severe influenza-related outcomes, including hospitalizations and medical encounters. Multiple studies in the analysis also suggested that vaccination with QIVc had incremental benefits over QIVe in these same outcomes. While immunization with egg-based vaccines was protective against severe illness compared to no vaccination, the potential for additional protection offered by cell-based vaccines is an important consideration in vaccination practices for vulnerable populations like young children. While this study demonstrated benefits of QIVc vaccination on severe outcomes, inherent qualities of subgroup analyses limit the generalizations that can be made across populations. With more robust data on pediatric populations specifically, a formal meta-analysis may be possible and may give researchers further insights into the benefits of cell-based influenza vaccination (including on influenza infection and mild cases). 4

Reducing the risk of serious influenza-related outcomes in children can play a significant role in community and public health. Children are at higher risk for developing serious influenza-related complications and may be more likely to spread illness through exposure in highly populated environments.3 The study also found that there may be additional benefits to health systems and economies, as three health economics studies focusing on a pediatric population also found the use of QIVc to be cost-effective or cost-saving. One of these studies, which was conducted in the U.S., compared potential effects of vaccinating children with QIVc instead of egg-based vaccines. Findings suggested that the practice helped prevent up to 31,000 hospitalizations and 4,000 deaths, and could lead to cost reductions of approximately $400 million–$1.4 billion depending on the type of flu season, driven by reduction in costs from healthcare visits, hospitalizations, and deaths. The other studies, conducted in Italy and Taiwan, produced similar findings.4

Vaccinating eligible people can help reduce influenza-like illness and complications, and new analyses can help support pharmacists as critical sources of knowledge and resources around influenza. By staying attuned to current research and understanding the benefits of newer vaccine technologies, pharmacists can make evidence-based decisions when providing influenza vaccines, supporting their key role in selecting and administering appropriate flu vaccines to higher risk groups and to the general public.


1. CDC. Past seasons estimated influenza disease burden. 2023. Accessed December 2023.
2. Adalja AA, Crooke PS, Hotchkiss JR. Influenza transmission in preschools: modulation by contact landscapes and interventions. Math Model Nat Phenom. 2010;5(3):3-14.
3. CDC. Flu vaccines are important for children. 2023. Accessed December 2023.
4. Mould-Quevedo JF, Pelton SI, Nguyen VH. Vaccine effectiveness of cell-based quadrivalent influenza vaccine in children: a narrative review. Vaccines. 2023; 11(10):1594.