Influenza is an important public health problem that poses a challenge the health care system every year.

At the global level, it affects 30%–40% of the pediatric population each season, with nearly one million severe cases in children younger than 5 years. In addition, children are the main transmitters of the disease.

Vaccination is the most effective preventive measure against influenza, as, in addition to conferring individual protection to the child or adolescent, it significantly contributes to the protection of the family and the community. The World Health Organization (WHO) and the Spanish Ministry of Health recommend routine vaccination of children aged 6–59 months. The CAV-AEP (Advisory Committee on Vaccines of the Asociación Española de Pediatría [Spanish Association of Pediatrics]) has extended the recommendation for routine vaccination to age 17 years.

Vaccination of influenza is prioritized in individuals who are at risk, including children, on account of their increased vulnerability and higher incidence of severe disease, as well as their household contacts. Due to the particular characteristics of the pediatric population, additional promotion measures may be needed to achieve an adequate vaccination coverage.

This consensus document describes the influenza vaccine composition recommended by the WHO for the 2025–2026 season in the northern hemisphere and the vaccines available in Spain for pediatric patients. It describes practical aspects concerning dosage, administration and storage, summarizes the current evidence on their effectiveness in children and adolescents, highlights strategies for achieving high vaccine uptakes and analyzes important aspects such as safety, contraindications and precautions that providers need to be aware of.

The intranasal live attenuated influenza vaccine is recommended for children and adolescents aged 2–17 years due to its greater acceptability, which contributes to improving vaccine uptake, and its greater effectiveness, particularly after the administration of only one dose. This vaccine has the ability to simulate natural infection and induce a comparable humoral and cellular response that begins in the respiratory mucosa. Table 1 summarizes the recommendations for the 2025–2026 season.

Every year, there are one thousand million cases of seasonal influenza worldwide, including 3–5 million severe cases and 290 000–650 000 deaths.1,2 The proportion of the pediatric population affected by the disease ranges between 30% and 40% depending on the year, with 2–4 million severe cases in children younger than 18 years and up to 35 000 deaths in children aged less than 5 years.3 Recent data from the United States show an increase in mortality in the group aged 5–17 years compared to previous years,4,5 while data from Australia shows an increase in admissions to the intensive care unit (ICU) in children aged 5–9 years.6

Every season, children under 15 are the group with the highest incidence of influenza. In Spain, data on influenza activity in the 2024–2025 season provided by the acute respiratory infection surveillance system (SIVIRA)7 show that the incidence of influenza managed at the primary care (PC) level decreased after the introduction of routine vaccination in children aged 6–59 months, especially after the second campaign (2024–2025), becoming lower compared to the group aged 5–19 years.

The hospitalization rate associated with influenza varies according to age and is highest in the first months of life. In healthy children younger than 4 years, the hospitalization rate is similar to that of older adults aged 65–79 years.7

Due to the aforementioned reasons (incidence, hospitalization, ICU admissions) in addition to the role of children as transmitters of influenza in the community, we recommend extending routine vaccination against influenza to children aged up to 17 years.

Every year, the WHO issues recommendations regarding the composition of the seasonal influenza vaccines aiming to match the circulating strains in each hemisphere.

Since the 2024–2025 season, the WHO has recommended the use of trivalent excluding the B/Yamagata lineage due to the lack of detection of viruses of this lineage since 2020. For the upcoming 2025–2026 season, it has introduced changes in the H3N2 strains recommended for inclusion compared to the previous season8 (Table 2).

In Spain, seven vaccine formulations, all of them trivalent, will be distributed for the upcoming season, of which five (4 inactivated and 1 live attenuated) are authorized for use in children and adolescents (Table 3). One of the inactivated vaccines is obtained from cell cultures and the other three, in addition to the attenuated vaccine, are manufactured using fertilized chicken eggs.

Although the official schedule for vaccination against influenza in healthy children aged less than 9 years who are being vaccinated for the first time, in agreement with the summary of product characteristics, calls administration of two doses at least four weeks apart,9 the Public Health Committee of the Interterritorial Council of the National Health System of Spain10 recommends administration of a single dose to streamline vaccination logistics and improve vaccination coverage.

Two doses should only be administered to children in risk groups aged less than 9 years the first season they are vaccinated against influenza. If they have received one or more doses in a previous campaign, a single dose should be administered in the current campaign11 (Table 4).

All inactivated vaccines can be administered from 6 months of age. The intranasal attenuated vaccine is authorized for use from 2 to 17 years of age. The dose for all ages is 0.5 mL for inactivated vaccines and 0.2 mL (0.1 mL in each nostril) for the intranasal attenuated vaccine.

The vaccine effectiveness (VE) of influenza vaccines in reducing confirmed influenza, influenza-associated hospital admission and preventing fatalities varies based on the characteristics of the population, the type of vaccine used, the viruses circulating in the season and the match with the viruses contained in the vaccines, among other factors.12

With respect to the VE in the pediatric population, it is generally higher compared to the adult population and ranges between 25.6% and 78.8%.13 A systematic review found a VE for preventing hospitalization of 57.4% (95% CI, 49.4%–65.4%), with a higher effectiveness against H1N1 (74.0%; 95% CI, 54.8%–93.3%) compared to type B (50.8%; 95% CI, 41.7%–59.9%), and moderate effectiveness against H3N2 (40.7%; 95% CI, 25.6%–55.8%). Vaccine effectiveness was higher in children aged less than 5 years (61.7%; 95% CI, 49.2%–74.1%) and 5–17 years (54.3%; 95% CI, 35.1%–73.6%).14

In the 2022–2023 season, the VE in Andalusia was 51% (95% CI, 48%–53%) for preventing infection and 69% (95% CI, 56%–79%) for preventing hospitalization due to influenza.15

In Spain, a case-control study with effectiveness data from the 2023−24 season showed an adjusted VE of 70% (95% CI, 51%–81% CI) for prevention of acute respiratory disease managed at the PC level and 77% (95% CI, 21%–93% CI) for prevention of hospitalization due to severe respiratory disease.16

Influenza vaccines have a high safety profile with a favorable risk-benefit balance.

The most common adverse effects with inactivated vaccines are local reactions (redness, tenderness). Systemic adverse events include fever, myalgia and fatigue, with a frequency ranging from 5% to 20%. Usually, these effects are mild and do not require medical attention.17

With the attenuated vaccine, the most common adverse reactions are nasal congestion and fever. In a prospective observational study,18 the most frequently observed adverse events were lower respiratory tract infection and wheezing, although there was not an associated increase in the incidence of hospitalization due to these events compared to the unvaccinated.

A history of anaphylactic reaction to any vaccine component or to a previous dose of influenza vaccine is considered an absolute contraindication for the influenza vaccine. The recommendations for influenza vaccination in individuals with egg allergies are discussed in a separate section of this document.

The attenuated influenza vaccine is also contraindicated in:

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  Immunocompromised individuals, with the exception of children with stable HIV infection with adequate immune function and receiving antiretroviral therapy.

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  According to the summary of product characteristics, it would be contraindicated in individuals with egg allergy, although both the CAV-AEP11 and Spanish Ministry of Health,10 as well as the Centers for Disease Control and Prevention (CDC),19 allow its use with the precautions recommended for all other vaccines.

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  Household contacts of severely immunocompromised individuals. If they receive this vaccine due to error, contact needs to be avoided for 1–2 weeks following vaccination.

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  Children aged 2–17 years currently medicated with aspirin or any other treatment containing acetylsalicylic acid due to the association with Reye syndrome.

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  Pregnant women, due to the lack of safety data.

The attenuated vaccine must be used with caution in individuals with severe asthma or active wheezing, as these conditions were not studied during clinical trials.20 The CDC of the United States consider it contraindicated in children aged 2–4 years with asthma or who have had a wheezing episode in the past 12 months, while they recommend precaution in children aged 5 or more years with asthma on account of an increased risk of wheezing following vaccination.21 However, a trial in children aged 5–17 years with asthma found no significant differences in the frequency of asthma-related symptoms or changes in lung function tests in the 14 days that followed vaccination with the use of the attenuated vaccine compared to the inactivated vaccine.22

There is no evidence in children that vaccination against influenza is a risk factor for Guillain-Barré syndrome (GBS). In addition, it is estimated that the risk of developing GBS after an influenza infection is greater than the risk associated with vaccination.23,24 As a precaution, administration of additional doses is discouraged in healthy children who developed GBS within 6 weeks of receiving the influenza vaccine, although vaccination in subsequent seasons should still be considered in children with underlying diseases, in whom its benefits exceed the hypothetical risk.25,26

Caution must be exerted in children who developed immune thrombocytopaenic purpura in the week following receipt of the inactivated influenza vaccine. Given the risk of recurrence, the appropriateness of vaccination should be determined on a case-by-case basis.25

The American Academy of Pediatrics (AAP),27 the CDC, the CAV-AEP and the Spanish Ministry of Health all consider that influenza vaccines can be co-administered with other vaccines in the child and adolescent immunization schedule. The intranasal vaccine can be administered with other parenteral or oral attenuated vaccines on the same day or as apart as desired.

In adherence with the recommendations made by the WHO in 2012,28 the CAV-AEP (since 2021) and the Public Health Committee (since 2022) in Spain recommend routine vaccination of children aged 6–59 months.29

It is well known that childhood vaccination has a significant impact on the transmission of influenza viruses and in reducing the incidence of influenza and its complications. In consequence, some countries extend vaccination beyond 5 years of age, such as the United Kingdom (up to 17 years), as it is a cost-effective measure30 with a direct and indirect impact in terms of a reduction in the number of primary care and emergency department visits and hospitalization of children and adolescents and protection of unvaccinated adults.31

For all the above reasons, this consensus statement recommends extending vaccination through age 17 years, emphasizing the importance of vaccination in people with risk conditions and their household contacts. Extended vaccination would help increase vaccination coverage in this group.

Table 5 presents the recommendations for vaccination against influenza.

In addition to the recommendation for routine vaccination against influenza in children and adolescents, it is essential to implement high-impact strategies to increase vaccination coverage, as some autonomous communities are already doing:

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  Training of healthcare professionals: an essential measure, as they are responsible for providing information appropriately. It is the responsibility of both health care professionals and health care authorities and scientific societies to establish appropriate channels for this training.

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  Active recommendation by health care professionals is the most important factor contributing to the decision of parents to vaccinate their children.38 There is evidence of an association between higher vaccination coverage and higher frequency of active recommendation of vaccination by health care providers.

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  Informing the population: conventional promotion tools, such as posters, do not boost vaccination coverage. The dissemination of information through social media, digital platforms, conventional mass-media and in pharmacies can help reach parents, vulnerable groups or individuals with language barriers.

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  Active engagement: as occurred with immunization against respiratory syncytial virus, active engagement and promotion can achieve substantial increases in coverage while also reaching vulnerable groups, such as patients at risk.

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  Improving accessibility of vaccination: this is crucial since, as vaccination against influenza is delivered in seasonal campaigns, additional efforts must be made to ensure that all groups have access to it. Vaccination in schools, walk-in vaccination, weekend vaccination clinics and opening of primary care centers in the afternoons, which make vaccination accessible for families outside regular working hours, have been found to increase vaccination coverage.

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  Increasing acceptability: the availability of an intranasal vaccine has improved coverage, especially in school vaccination campaigns. There is evidence that the attenuated vaccine is widely accepted by children, parents, and health care professionals.38,39

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  Alignment of public health administrators and scientific societies: it is important for both citizens and professionals to perceive that there is agreement between the recommendations of health authorities and scientific societies, as this reinforces the overall confidence in vaccination.

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  Communicating up-to-date information on the health outcomes of vaccination campaigns to professionals and citizens, strengthening confidence in vaccination and allowing corrective measures to be taken to increase the effectiveness and efficiency of the program.

The development of these recommendations (analysis of the published data, debate, consensus and publication) has not been supported by any funding source outside of the logistic support provided by the AEP.