Seasonal Influenza Vaccine Effectiveness and Safety in Asthma

Date of Approval: 
2018-05-22 00:00:00
Lay Summary: 
In the UK and worldwide flu vaccination for people aged six months or older in winter is the recommended way to prevent flu in risk groups such as people with asthma. However, it is not clear how well the vaccine protects asthma patients from flu and how safe the live vaccine (nasal spray) is for young children with asthma. This study aims to assess how well the flu vaccine works for people with asthma against illnesses such as flu, pneumonia and middle ear infection. It also aims to assess how safe the flu nasal spray is by looking at side effects such as asthma attacks in children with asthma. To do this, we will investigate how well the flu vaccine protects people with asthma from flu-related illness by comparing health data of people who got the vaccine to those who did not. We will also investigate the vaccine’s side effects on children that got the nasal spray by comparing a child’s side-effects shortly after getting the vaccine with the same child’s risk-free periods. Findings from this research will help the flu vaccination programme improve the health of people with asthma by reducing flu-related complications.
Technical Summary: 
Influenza causes considerable morbidity and mortality among individuals with chronic underlying conditions such as asthma. In the UK current policy recommends all individuals with asthma to be immunised with the influenza vaccine. However, the vaccine uptake rates remain suboptimal in asthma partially due lack of strong evidence on the vaccine effectiveness and safety concerns particularly for the new childhood live attenuated vaccine from parents and healthcare providers. The aim of this project is to provide national estimates of the effectiveness and safety of influenza vaccine amongst people with asthma. A longitudinal retrospective cohort study will be undertaken to estimate the vaccine effectiveness in asthma against clinical outcomes such asthma influenza illness, asthma exacerbations and mortality. A Cox proportional hazards model will be used to estimate the hazard ratios (HRs) of all clinical outcomes adjusted for all patient characteristics. The vaccine effectiveness will be estimated from the HRs for each clinical outcome for seasons 2000-2017. A self-controlled case series study design will assess the safety of the live vaccine in young children with asthma against any vaccine-induced adverse events such as asthma attacks for seasons 2013-2017. Only vaccinated cases will be used to estimate the relative risk of adverse events.
Health Outcomes to be Measured: 
Asthma exacerbations Hospital admission due to influenza/pneumonia Antibiotic prescription related to a respiratory infection or otitis media Influenza or influenza-like illness Death Adverse events related to influenza vaccines Primary care consultation due to influenza/pneumonia Acute respiratory infection or otitis media or any other respiratory infection
Application Number: 
18_056
Collaborators: 

Colin Simpson - Chief Investigator - University of Edinburgh
Eleftheria Vasileiou - Corresponding Applicant - University of Edinburgh
Aziz Sheikh - Collaborator - University of Edinburgh
Chris Robertson - Collaborator - University Of Strathclyde
Christopher Butler - Collaborator - University of Oxford

Linkages: 
CPRD Mother-Baby Link;HES Accident and Emergency;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Pregnancy Register