- Article
- Source: Campus Sanofi
- 25 Jun 2024
Burden of Influenza
What is the burden of influenza for at-risk patients?
Some people may be at increased risk of influenza-related complications, including:1
Adults aged 65 years and over may be at increased risk of flu-related complications as a result of a weakened immune system that occurs with age.1,2 Flu may cause pneumonia and other respiratory complications.3 In more serious cases, particularly if these patients have any other underlying health conditions, flu could also lead to permanent disability or death.3
Chronic respiratory conditions
Patients with chronic respiratory conditions may be at increased risk of serious flu-related complications.1 This is because flu is a respiratory virus that can make existing breathing conditions worse by putting extra strain on the lungs.4 A respiratory condition may also limit the types of medicines that can be given to treat flu in these patients, potentially causing longer recovery times and a need for hospitalisation.4
Chronic heart conditions
Patients with chronic heart conditions may be at increased risk of serious flu-related complications.5 Flu complications can be severe for patients with heart disease and can lead to considerable morbidity and mortality.6,7
Chronic kidney disease
Patients with chronic kidney disease (CKD) may be at increased risk of serious flu-related complications due to the immune dysfunction that accompanies this condition.8,9 CKD may also increase the risk of mortality for patients compared with healthy people.10
Chronic liver conditions
Patients with chronic liver disease may be at increased risk of serious flu-related complications due to the immune dysfunction that accompanies this condition.11,12 These complications may also increase the risk of mortality in patients.12 Chronic liver conditions may limit the types of medicines that can be given to treat flu, potentially causing longer recovery times and the need for hospitalisation.13
Chronic neurological conditions
Patients with a chronic neurological condition may be at increased risk of serious flu-related complications.1,14 Flu can worsen existing neurological symptoms, for example difficulty breathing, or regulating body temperature. This can lead to other complications, such as pneumonia, and increase the risk of hospitalisation.14 Studies have also shown that flu can cause a relapse in one third of patients with multiple sclerosis within 6 weeks.14
Diabetes
Patients with diabetes may be at increased risk of serious flu-related complications, for example pneumonia.15,16 Flu may increase a patient’s blood sugar levels, which can lead to diabetic complications including ketoacidosis and hyperglycaemic hyperosmolar non-ketotic coma.17 Flu-related challenges in managing blood sugar levels may also slow diabetic patients’ recovery time from flu.16
Immunosuppression
Patients who are immunosuppressed may be at increased risk of flu-related complications.1 These may include lower respiratory tract infections, and in some unusual manifestations, rhabdomyolysis and myocarditis.18 As a result of these complications, those who are immunosuppressed may also have a higher risk of mortality and morbidity from flu.1,19
Asplenia or dysfunction of the spleen
Patients with asplenia (an absent or dysfunctional spleen [including conditions like sickle cell and coeliac disease), may be at increased risk of certain infections, such as flu,20 due to an impaired immune system.21 The spleen helps fight invading pathogens in the blood, with the help of white blood cells.21 When the spleen is not working properly, patients may be less able to tackle infections like flu.21
Morbid obesity (BMI ≥40 kg/m2)
Adults with a body mass index (BMI) of ≥40 kg/m2 may be at increased risk of flu-related complications.1,22 These may include pneumonia and damage to the lungs and could increase the need for hospitalisation.23 In some cases, these flu-related complications may also be linked to a higher risk of mortality.23 Many patients in this group may already be eligible for a flu vaccination, due to complications of obesity that put them in another at-risk group.1
The risk of serious illness from flu is increased during pregnancy as a result of changes to the immune system to support the growing baby.1,24 Vaccination during pregnancy can provide passive immunity to the baby for the first few months of life and can reduce the risk of premature birth and low birth weight. 1,25–27
Children may be at greater risk of flu-related complications.1 It is recommended that at-risk children aged from 6 months and children not at risk aged 2 years to under 17 years are vaccinated.1 Flu-related complications for this group can include pneumonia, dehydration, brain dysfunction, sinus problems and in some cases, can lead to death.28
Flu vaccination is an essential part of helping protect communities29
What are the complications associated with the burden of Influenza?
Influenza may trigger other unwanted health complications for patients
Evidence indicates that influenza may trigger severe cardiovascular complications beyond respiratory infection.7
A self-controlled case series study conducted in Scotland showed that adults aged 40 years and older (median age 68), without a history of heart attack or stroke, were at a significantly increased risk of severe cardiovascular complications in the 1–3 days following a confirmed influenza infection.7
In the 1–3 days following a laboratory-confirmed influenza infection:a
Risk of having a heart attack7
Risk of having a stroke7
aIn a self-controlled case series study (based on a population in Scotland 2004-2014) conducted on a database of adults aged ≥ 40 years with ~90% of the study population aged 50 years and older. In the 1–3 days following a laboratory-confirmed influenza infection versus unexpected or baseline time periods.
CI, confidence interval; IR, incidence ratio.
Hospitalisations and economic burden of influenza
Influenza has an associated impact on healthcare costs and resources.
Influenza may have a considerable burden on secondary healthcare systems.30
Hospital admissions during the 2018/19 influenza season had associated medical costs of £99,565,310.1 The highest costs were found to be associated with patients aged 65+ years.30
Certain groups may create increased pressure as they are more likely to experience a longer and more severe illness. During the 2018/19 influenza season:30
| <65 years |
75+ years |
|
Costs per hospitalisation: ~£1,900 |
Costs per hospitalisation: ~£3,700 |
|
Average length of stay: 4.74 days |
Average length of stay: 12.55 days |
|
Mortality: 1.83% |
Mortality: 11.18% |
References
- https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1176378/UKHSA_12699_Flu_Vaccination_main_leaflet___Winter_2023-2024_04_WEB.pdf Green book. Chapter 19. Influenza. (2020). https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/931139/Green_book_chapter_19_influenza_V7_OCT_2020.pdf (Accessed June 2024).
- Haralambieva IH, et al. PLoS One. 2015;10:e0122282.
- NHS. The flu vaccination. Who should have it and why. Winter 2023 to 2024. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1176378/UKHSA_12699_Flu_Vaccination_main_leaflet___Winter_2023-2024_04_WEB.pdf (Accessed June 2024)
- NHS. Flu vaccinations and long term respiratory conditions. https://www.aspenmedicalpractice.nhs.uk/wp-content/uploads/2019/10/Respiratory-Conditions-and-Flu-Vaccine-Importance.pdf (Accessed June 2024)
- BHF. Flu and your heart condition. https://www.bhf.org.uk/informationsupport/support/practical-support/flu-and-your-heart-condition (Accessed June 2024)
- Fukuta H, et al. Heart Fail Rev. 2019;24:109–14.
- Warren-Gash C, et al. Eur Respir J. 2018;29:1701794.
- CDC. Flu and people with chronic kidney disease. https://www.cdc.gov/flu/highrisk/chronic-kidney-disease.htm (Accessed June 2024).
- Grzegorzewska AE. Hum Vaccin Immunother. 2015;11:2599–605.
- Centers for Disease Control and Prevention. Flu & people with chronic kidney disease. https://www.cdc.gov/flu/highrisk/chronic-kidney-disease.htm (Accessed June 2024)
- British Liver Trust. Get the flu jab. https://britishlivertrust.org.uk/about-us/what-we-do/campaigns/get-the-jab/ (Accessed June 2024).
- Härmälä S, et al. BMJ Open. 2019;9:e031070.
- NHS. flu vaccinations and chronic liver disease. https://www.aspenmedicalpractice.nhs.uk/wp-content/uploads/2019/10/Liver-Disease-and-Flu-Vaccine-Importance.pdf (Accessed June 2024)
- NHS. Flu vaccinations and chronic neurological disease. https://www.aspenmedicalpractice.nhs.uk/wp-content/uploads/2019/10/Neurological-Disease-and-Flu-Vaccine-Importance.pdf (Accessed June 2024)
- NHS. Flu vaccinations and diabetes. https://www.aspenmedicalpractice.nhs.uk/wp-content/uploads/2019/10/Diabetes-and-Flu-Vaccine-Importance.pdf (Accessed June 2024)
- Diabetes UK. Flu jab and diabetes. https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/flu-jab (Accessed June 2024).
- Sellers SA, et al. Influenza Other Respir Viruses. 2017;11:372–93.
- Bosaeed M and Kumar D. Hum Vaccin Immunother. 2018;14:1311–22.
- Kumar D, et al. Clin Infect Dis. 2018;67:1322–9.
- NHS England. Vaccination audit for asplenic patients. https://www.england.nhs.uk/atlas_case_study/vaccination-audit-for-asplenic-patients/ (Accessed June 2024).
- NHS. Spleen problems and spleen removal. https://www.nhs.uk/conditions/spleen-problems-and-spleen-removal/ (Accessed June 2024)
- CDC. People at High Risk For Flu Complications. https://www.cdc.gov/flu/highrisk/index.htm (Accessed June 2024).
- Honce R and Schultz-Cherry S. Front Immunol. 2019;10:1071.
- Rasmussen SA, et al. Emerg Infect Dis. 2008;14:95–100.
- Pebody R, et al. Eurosurveillance. 2010;15:19571.
- Benowitz I, et al. Clin Infect Dis. 2010;51:1355–61.
- Omer SB, et al. PLoS Med. 2011;8:e1000441.
- CDC. Flu and young children. https://www.cdc.gov/flu/highrisk/children.htm (Accessed June 2024).
- Franklin B and Hochlaf D (2018). An economic analysis of flu vaccination. https://ilcuk.org.uk/an-economic-analysis-of-flu-vaccination/ (Accessed June 2024).
- Moss JWE, et al. BMC Public Health. 2020;20(1):1464.
MAT-XU-2301387 (v3.0) Date of preparation: June 2024