Gearing up for Influenza Season 2020-21 in the Northern Hemisphere:
Recommendations for Pediatric SOT Candidates & Recipients

The IPTA ID committee (IDCARE) wishes to provide a brief influenza update in preparation for the upcoming 2020-2021 season in the Northern Hemisphere.

Data from the 2019-2020 season

The epidemiology of the 2019-2020 influenza season was variable but in general, influenza activity ranged from moderate to very high across the globe.1 In the United States (US), the 2019-2020 influenza season was characterized by increased severity in children 0-4 years and adults 18-49 years of age when compared with the 2017-2018 high severity season; in total, at least 434 pediatric deaths were estimated to be associated with influenza during the 2019-2020 season.2,3

Preliminary/interim estimates of 2019-2020 influenza vaccine effectiveness (VE) from both Europe and the US are similar to prior seasons. Overall VE point estimates in Europe ranged between 29-61% (Europe) with VE in children <17 years ranging from 37-95% depending on the setting and the region.4 In the US, overall VE was 45% (95% CI 36-53%) and VE for pediatric patients (6 months-17 years) was 55% (95% CI 42-65%).5

Interim data from the 2020-2021 season

Recent data suggest that interventions aimed against SARS-CoV-2 transmission (wearing a mask, physical distancing, handwashing) in conjunction with influenza vaccination, could substantially reduce the incidence and impact of influenza on the 2020-2021 season in the Northern Hemisphere.6 With the onset of widespread community transmission of SARS-CoV-2 and implementation of transmission mitigation efforts worldwide at the beginning of 2020, a marked decrease in influenza circulation was noted at the end of the 2019-2020 Northern Hemisphere influenza season.6 Moreover, influenza activity from June to August 2020 in the Southern Hemisphere remained very low.6 Given concerns for likely co-circulation of seasonal influenza and SARS-CoV-2 and known morbidity attributable to influenza among SOT recipients7, caution should be used and preventative strategies optimized by SOT candidates, recipients, their families and healthcare providers. Influenza vaccination remains a critical intervention to prevent influenza infection in pediatric SOT recipients.

2020-2021 Influenza Vaccine Components

As in prior seasons, quadrivalent vaccines contain one influenza A H1N1 2009 pandemic-like virus, one influenza A H3N2 virus, and two influenza B viruses (one from the Yamagata lineage and one from the Victoria lineage). Trivalent vaccines contain one of the influenza B virus strains (from the Victoria lineage). World Health Organization (WHO) recommendations for the 2020-2021 Northern Hemisphere influenza season updated all components except for the Yamagata lineage influenza B component.8 For the 2021 Southern Hemisphere influenza season, components are similar to those seen in the 2020-2021 northern hemisphere season with the exception of the influenza A H1N1 pandemic 2009-like virus.9

Currently, there is very little influenza virus circulation in either the US ( or Europe (

Influenza Vaccine Recommendations

No major changes to influenza vaccination recommendations for children were made in the US for this season.10 European recommendations remain similar to prior years with some country-specific variability in influenza vaccine guidance.11

Highlights of current recommendations for influenza vaccination in pediatric SOT candidates and recipients:

  • All persons ≥ 6 months of age who do not have a contraindication to immunization should receive the inactivated influenza vaccine (IIV); IIV should be given as early as possible during the influenza season, preferably before influenza is circulating in the local community.10,12,13
    • Children 6 months to 8 years of age who are receiving IIV for the first time or did not receipt two IIV doses previously, should receive a 2-dose series, with a 4-week interval between doses.
  • There are few data to guide the optimal timing of IIV in children after SOT.
    • Currently, IIV should be provided to SOT recipients beginning at 3-4 months after SOT, when receiving maintenance immunosuppression.
    • Vaccination with IIV beginning as early as 1-2 months post-SOT may be considered if there is a community transmission of influenza. In this scenario, based on controlled data in adults, some experts may recommend a second dose of IIV to be given in the same season once the patient is receiving maintenance immunosuppression.14-16
  • Household contacts, caregivers, and health care workers providing care to children at higher risk for influenza complications (such as pediatric SOT) should also receive yearly influenza vaccination.
  • Receipt of influenza vaccination does not protect against COVID-19; there are no associations with influenza vaccination and risk for COVID-19.17
  • Influenza vaccination is safe and immunogenic in SOT recipients, but protection is not absolute. SOT recipients who develop influenza infection are at higher risk for influenza-associated complications and thus, are candidates for antiviral therapy, regardless of vaccination status or duration of symptoms.10,18

Prepared by D Dulek and MI Ardura, on behalf of the IPTA IDCARE committee

Additional influenza resources:


  • 1. European Centre for Disease Prevention and Control and World Health Organization: Regional Situation Assessment - Seasonal Influenza. (Accessed 11/2/2020, at
  • 2. CDC. Estimated Influenza Illnesses, Medical visits, Hospitalizations, and Deaths in the United States: 2019-2020 Influenza Season. (Accessed 11/2/2020, at
  • 3. CDC. 2019-20 Season's Pediatric Flu Deaths Tie High Mark Set During 2017-18 Season. (Accessed 11/2/2020, at
  • 4. Rose A, Kissling E, Emborg HD, et al. Interim 2019/20 influenza vaccine effectiveness: six European studies, September 2019 to January 2020. Euro Surveill 2020;25.
  • 5. Dawood FS, Chung JR, Kim SS, et al. Interim Estimates of 2019-20 Seasonal Influenza Vaccine Effectiveness - United States, February 2020. MMWR Morb Mortal Wkly Rep 2020;69:177-82.
  • 6. Olsen SJ, Azziz-Baumgartner E, Budd AP, et al. Decreased Influenza Activity During the COVID-19 Pandemic - United States, Australia, Chile, and South Africa, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1305-9.
  • 7. Kumar D, Michaels MG, Morris MI, et al. Outcomes from pandemic influenza A H1N1 infection in recipients of solid-organ transplants: a multicentre cohort study. Lancet Infect Dis 2010;10:521-6.
  • 8. WHO. Recommended composition of influenza virus vaccines for use in the 2020-2021 northern hemisphere influenza season. 11/2/2020, at
  • 9. WHO. Recommended composition of influenza virus vaccines for use in teh 2021 southern hemisphere influenza season. at
  • 10. Grohskopf LA, Alyanak E, Broder KR, et al. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices - United States, 2020-21 Influenza Season. MMWR Recomm Rep 2020;69:1-24.
  • 11. European Centre for Disease Prevention and Control. Prevention and Control of Seasonal Influenza. (Accessed 11/2/2020, at
  • 12. Danziger-Isakov L, Kumar D, Practice AICo. Vaccination of solid organ transplant candidates and recipients: Guidelines from the American society of transplantation infectious diseases community of practice. Clin Transplant 2019;33:e13563.
  • 13. Committee on Infectious D. Recommendations for Prevention and Control of Influenza in Children, 2020-2021. Pediatrics 2020;146.
  • 14. Cordero E, Roca-Oporto C, Bulnes-Ramos A, et al. Two Doses of Inactivated Influenza Vaccine Improve Immune Response in Solid Organ Transplant Recipients: Results of TRANSGRIPE 1-2, a Randomized Controlled Clinical Trial. Clin Infect Dis 2017;64:829-38.
  • 15. Dulek DE, de St Maurice A, Halasa NB. Vaccines in pediatric transplant recipients-Past, present, and future. Pediatr Transplant 2018;22:e13282.
  • 16. Haddadin Z, Krueger K, Thomas LD, Overton ET, Ison M, Halasa N. Alternative strategies of posttransplant influenza vaccination in adult solid organ transplant recipients. Am J Transplant 2020.
  • 17. Skowronski DM, Zou M, Clarke Q, et al. Influenza vaccine does not increase the risk of coronavirus or other non-influenza respiratory viruses: retrospective analysis from Canada, 2010-11 to 2016-17. Clin Infect Dis 2020.
  • 18. Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa. Clin Infect Dis 2019;68:895-902.



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