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Completed

NCT Number: NCT06077045

Uptake of the Childhood Live Attenuated Influenza Vaccine (LAIV) and Influenza-related Healthcare Resource Use in England During the 2012 to 2022 Flu Seasons; a Retrospective, Observational Study in the CPRD and HES Databases

In 2013, the NHS started a vaccination program in some regions of England to provide free flu vaccines to children aged 2 years or older, and younger than 16 years. The program has since been rolled out across England. Most children are given a vaccine that is sprayed into their nose. In clinical trials, this vaccine has been shown to protect children from experiencing severe flu symptoms. It is important to describe how it is used, and what happens to children who receive it in the wider community. This evidence will help the NHS to check that the vaccine roll out runs as planned and produces the intended benefits.

This study aims to: (1) describe how many children each year receive flu vaccines, and describe the characteristics of children who are and aren't vaccinated for influenza; (2) test how often children receiving the vaccine see their GP or a hospital doctor for symptoms related to flu, compared to those who don't; and (3) to test what groups of children are more or less likely to receive a flu vaccine. To answer these objectives, the study will use the Clinical Practice Research Datalink, linked to Hospital Episode Statistics and the Office for National Statistics database.

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Key information

Conditions

Influenza Infections Influenza, Human Orthomyxoviridae Infections RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

0 year–17 year

Sex eligibility

All sexes

Study type

Observational

Primary location

CPRD

London, United Kingdom

About this study

A Live Attenuated Influenza Vaccination (LAIV) has been offered to children through a rolling national program in England since 2013. Previous observational studies identified trends in LAIV uptake that varied with demographic and clinical profiles.

The general aim of this study is to provide up-to-date epidemiological evidence on the uptake of the influenza vaccines, and influenza related HCRU outcomes in children in England. The specific study objectives are given below.

Primary objective:

  • To evaluate the uptake of influenza vaccines in children aged ≥2 and <18 years in England between 2012 and 2020 for LAIV, QIV, and influenza vaccinations where the product is not specified

Secondary objectives:

2.1 To describe usage patterns of LAIV in England between 2012 and 2020. 2.2 To describe HCRU associated with laboratory confirmed influenza and/or influenza-like-illness (ILI) in England between 2012 and 2020 and assess the relative impact of LAIV on HCRU use of LAIV vs no vaccination 2.3 To describe demographics and clinical characteristics of individuals vaccinated with LAIV or not vaccinated against flu by any vaccine in each flu season between 2012 and 2020 2.4 To estimate a DAG aligned model for LAIV uptake in England based on demographic and clinical factors for each flu season and across multiple seasons between 2012 and 2020

The study will include all research eligible aged between ≥2 and <18 years in the study period, with 6 months of history in CPRD before their first influenza vaccination. It will use the Clinical Practice Research Datalink data (vaccinations, diagnoses, characteristics) linked to Hospital Episode Statistics (HCRU). Logistic regression analyses will be used to test for factors associated with vaccine uptake, and outcomes between vaccinated and unvaccinated children. The study will provide up-to-date epidemiological evidence on the uptake of LAIV and its impact on HCRU related to ILI in children in England. This may be used by the NHS for planning and evaluation of the childhood influenza vaccination program.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

The reference study cohort will include patients as follows:

  • Aged ≥2 and <18 years at any time between 1 September 2012 and 30 April 2020
  • Classified as eligible for inclusion in research analysis according to CPRD guidance

In each flu season, the following criteria apply:

Inclusion criteria

  • Aged ≥6 months and <2 years on the 1st September
  • Have a high-risk condition as listed in the Green Book.

Exclusion criteria

  • Were deceased or had migrated out of their practice prior to the 1st September in the current influenza season.
  • Were recorded has receiving both QIV and LAIV in the current influenza season.

Treatment and study plan

Primary outcomes

  1. Uptake of influenza vaccination

    Time frame: Per flu season (defined as 1st September in a given year to the 30th April the following year )

    Proportion of eligible individuals receiving a flu vaccine (LAIV, QIV, other)

Secondary outcomes

  1. GP consultations for ILI (influenza-like illness)

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Rate of GP consultations for ILI per 100,000 person years.

  2. Laboratory confirmed influenza

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Rate of Laboratory confirmed influenza for ILI per 100,000 person years.

  3. Admitted Patient Care (APC) episodes associated with ILI

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Rate of Admitted Patient Care (APC) for ILI per 100,000 person years.

  4. Accident and Emergency (A&E) attendances associated with ILI

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Rate of A&E for ILI per 100,000 person years.

  5. Outpatient attendances associated with ILI

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Rate of Outpatient attendances associated with ILI per 100,000 person years.

  6. Length of stay in APC for influenza and ILI

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Average length of stay in hospital for influenza and ILI

  7. Number of antibiotic prescriptions

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Counts of antibiotic prescriptions

  8. Number of antiviral prescriptions

    Time frame: From vaccination date until the earliest of death, de-registration, or the end of the influenza season (30th April of the second calendar year the season spans).

    Counts of antiviral prescriptions

Sponsors and collaborators

Lead sponsor

AstraZeneca

Industry

Registry information

Acronym: INOCULATE

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
Oct 11, 2023
Registry last updated
Apr 27, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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