ÌìÃÀÓ°Ôº

About this report

This report explains the quality and methodology information (QMI) for the Cover of vaccination evaluated rapidly programme official/accredited official statistics published by the UK Health Security Agency (UKHSA).

This QMI report helps users understand the strengths and limitations of the statistics and explains how we meet the quality standards stated in the . The report explains:

• the strengths and limitations of the data used to produce the statistics
• the methods used to produce the statistics
• the quality of the statistical outputs

About the statistics

These publications report childhood vaccination statistics in England on a quarterly and annual basis, relating to the routine vaccinations offered to all children up to the age of 5 years.

The statistics show the number of children vaccinated as a proportion of the eligible population (coverage) and are derived from information collected by the UK Health Security Agency (UKHSA) through the Cover of vaccination evaluated rapidly (COVER) programme.

The European Region of the World Health Organization (WHO) currently recommends that on a national basis at least 95% of children are immunised against diseases preventable by immunisation and targeted for elimination or control. These diseases are specifically, diphtheria, neonatal tetanus, pertussis, polio, Haemophilus influenzae type b (Hib), hepatitis B, measles, mumps and congenital rubella.

The WHO and the Joint Committee on Vaccination and Immunisation (JCVI) recommend immunisation against these diseases. UKHSA defines the reporting requirements for COVER.

These statistics:

• include changes to the vaccination schedule meaning that you cannot always compare changes in vaccine coverage over time; where changes to the vaccination schedule occur, these are documented throughout the report and accompanying spreadsheet
• include both children registered at a GP and those not registered
• report coverage based on responsible population (patients registered with GPs based in that local authority and unregistered patients resident in that local authority) rather than resident population
• are published in compliance with the information standard under

You can use these statistics to:

• extract the official estimates of vaccination coverage
• understand trends of vaccination coverage by upper tier local authority (UTLA) over time
• compare vaccination coverage across different geographies

You should not use the statistics to:

• evaluate whether children are being vaccinated on time according to the schedule

Geographical coverage: Coverage is reported for the United Kingdom and by country. Within England, coverage is reported by UTLA and UKHSA region.

Publication frequency: quarterly and annually

Changelog

26 June 2025: QMI report first published.

Contact

Lead analyst: Saira Butt

Contact email: cover@ukhsa.gov.uk

Suitable data sources

Statistics should be based on the most appropriate data to meet intended uses.

This section describes the data used to produce the statistics.

Data sources

Information on childhood immunisation coverage at ages 3 months, 12 months, 24 months and 5 years are collected from Child Health Information Systems (CHISs) for most local authorities or from general practice (GP) systems for a small number of local authorities. CHISs are computerised systems storing clinical records supporting health promotion and prevention activities for children, including immunisation, such as:

• information on childhood immunisation coverage at ages 12 months, 24 months and 5 years, collected through the UK COVER collection by UKHSA
• aggregated data collected from CHISs – in England, COVER data has been collected for UTLAs using the COVER data collection form, which can be found in the

Data quality

The data that we use to produce statistics must be fit for purpose. Poor quality data can cause errors and can hinder effective decision-making.

We have assessed the quality of the source data against the data quality dimensions in the Government Data Quality Framework.

This assessment covers the quality of the data that was used to produce the statistics, not the quality of the final statistics.

Due to a change in information system in quarter 2 of financial year (FY) 2024 to 2025, data quality issues were detected in quarter 3, resulting in the exclusion of data for 14 UTLAs from publication. Further corrections and validations have now been made, allowing the publication of the full data in quarter 3 and revised data in quarter 2. Additionally, to maintain consistency for the full financial year and align with the annual collection, data in quarter 1 was also republished.

A full record of data quality issues since 2018 to 2019 can be found in Appendix A.

Strengths and limitations of the data

The strengths of the data include:

• timely, comprehensive data and trends
• extensive data since 1987 allowing analysis of long-term trends in immunisation coverage
• inclusion of children not registered with a GP, providing a more complete assessment of coverage

The limitations of the data include:

• results based on aggregate data rather than individual vaccine records

• GPs use different systems to record and manage appointments, which can affect how accurate and complete the data is

• reported data based on vaccination status at specific timepoints rather than the age at which the vaccination was given

Accuracy

Accuracy is about the degree to which the data reflects the real world. This can refer to correct names, addresses or represent factual and up-to-date data.

COVER data is extracted from local CHIS systems which are maintained by CHIS providers. These providers ensure that records are kept up to date and aligned with COVER programme definitions. CHIS providers contact local authorities and GP practices to validate the data where there are any concerns.

Completeness

Completeness describes the degree to which records are present.

For a data set to be complete, all records are included, and the most important data is present in those records. This means that the data set contains all the records that it should, and that all essential values in a record are populated.

Completeness is not the same as accuracy as a full data set may still have incorrect values.

Childhood vaccine coverage is published for all local authorities and includes both children registered with GPs in that local authority and any children not registered with a GP residing within that local authority’s geographical boundary, except where noted. This provides a complete picture of all the children in the relevant age cohort for the whole UK.

Uniqueness

Uniqueness describes the degree to which there is no duplication in records. This means that the data contains only one record for each entity it represents, and each value is stored once.

Some fields, such as National Insurance number, should be unique. Some data is less likely to be unique, for example geographical data such as town of birth.

CHIS information technology (IT) providers are commissioned to conduct routine de-duplication of individual records by patient. This ensures that no children are counted simultaneously in more than one geographical area.

Consistency

Consistency describes the degree to which values in a data set do not contradict other values representing the same entity. For example, a mother’s date of birth should be before her child’s.

Data is consistent if it agrees with data in another data set. For example, the date of birth recorded for the same person in 2 different data sets should be the same.

Validations for consistency in the aggregated data are conducted at the point of data entry on the data entry form, and during UKHSA validation. Validations are carried out to check that vaccines given at the same time have similar coverage values and that the coverage for booster doses does not exceed the coverage of the primary course. 

Timeliness

Timeliness describes the degree to which the data is an accurate reflection of the period that it represents, and that the data and its values are up to date.

Some data, such as date of birth, may stay the same whereas some, such as income, may not.

Data is timely if the time lag between collection and availability is appropriate for the intended use.

COVER data is published on a quarterly and annual basis and reports on children who reached 3 months (BCG only), 12 months, 24 months or 5 years of age in the previous quarter or financial year. This means that the data may reflect vaccinations given months or even years earlier. The quarterly data is published at the end of the subsequent quarter: for example, data for quarter 1 is published at the end of quarter 2. The data is timely for the purposes of understanding the level of coverage among these age groups and trends over time.

Validity

Validity describes the degree to which the data is in the range and format expected. For example, date of birth does not exceed the present day and is within a reasonable range.

Valid data is stored in a data set in the appropriate format for that type of data. For example, a date of birth is stored in a date format rather than in plain text.

The COVER Information Standard ensures data outputs are consistent with the current UK vaccination programme and reporting requirements to ensure the final data reflects expected trends and differences.

Automated validations are carried out at the point of entry into the Strategic Data Collection Service (SDCS) template. The template performs basic automated checks which ensure all fields are complete. Further automated validation checks with manual review are then undertaken by UKHSA, which flag anomalies in local authority denominators and in individual vaccine antigen numerators. As data is aggregated before it is submitted to UKHSA, and all subsequent validation checks are based on aggregate data.

Sound methods

Statistical outputs should be produced using appropriate methods and recognised standards.

This section describes how the statistics were produced and quality assured.

Data set production

CHIS providers extract COVER data from local CHIS systems at the end of the reporting quarter or financial year. The data is submitted in an aggregate form via a standardised template, then compiled for all UTLAs by SDCS. SDCS then transmit the compiled data set to the UKHSA COVER team. All figures in the release are presented as simple counts or percentages (rounded to 1 decimal place). Coverage (which is explained below in the Definitions section, below) is reported for the following routine childhood vaccinations:

Table 1. Childhood vaccinations monitored by the COVER programme and age vaccination is reported

Childhood vaccination	Age reported at
Bacillus Calmette-Guérin (BCG)	3 months, 12 months
Neonatal hepatitis B (HepB) (selective programme)	12 months and 24 months
Diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b (DTaP/IPV/Hib) [note 1]	12 months, 24 months and 5 years
Rotavirus	12 months
Pneumococcal conjugate vaccine (PCV)	12 months
Meningococcal group B (MenB)	12 months
Pneumococcal conjugate vaccine (PCV) booster	24 months
Meningococcal group B (MenB)  booster	24 months
Haemophilus influenzae type b and meningococcal group C (Hib/MenC)	24 months and 5 years
Measles/mumps/rubella dose 1 (MMR1)	24 months and 5 years
Measles/mumps/rubella dose 2 (MMR2)	5 years
Diphtheria, tetanus, pertussis, polio (DTaP/IPV) booster	5 years

Note 1: Since August 2017, the 5-in-1 vaccine was replaced by the 6-in-1 vaccine which also protects against hepatitis B (DTaP/IPV/Hib/HepB).

Further information on the COVER specification criteria can be found in the .

Coverage for the selective hepatitis B and BCG programmes is also discussed in the main report. The quality of neonatal hepatitis B vaccine data varies and coverage can be based on small numbers. As such, comparisons of vaccine coverage should be considered alongside the number of children eligible for vaccination.

Definitions

Eligible population

Eligible population is defined as the total number of children in the local authority responsible population, reaching their first, second or fifth birthday in the collection year (see below for definition of ‘local authority responsible population’). Coverage is calculated for 3 separate cohorts (children reaching their first, second and fifth birthdays in the collection year) and so the eligible population differs for each cohort.

Reporting years

Reporting years are financial years (1 April to 31 March) rather than calendar years.

Coverage

Coverage is defined as the number of persons immunised as a proportion of the eligible population. The calculation of coverage is the total number of people immunised divided by the total number eligible in the population and multiplied by 100.

Immunised

Where a course consists of more than one dose of vaccine administered at set intervals, immunised means having had all doses required for a full course. However, for some vaccines such as Hib/MenC and PCV, the number of doses required to complete a course is age dependent. For example, a child who was not given the recommended 2 doses of PCV before 12 months but did receive a PCV booster dose after their first birthday will still be considered appropriately vaccinated for their age.

Local authority responsible population

Coverage figures are supplied for patients registered with GPs based in that local authority and for unregistered patients who were resident in that local authority. The local authority responsible population is therefore different from the estimated resident population figures produced by the Office for National Statistics (ONS) for each local authority. For the COVER programme, the local authority responsible population is usually derived from the population registers held on CHISs.

In previous years, for local authorities which were coterminous, sharing the same geographical boundaries as the old primary care trusts (PCTs), the local authority responsible population was estimated to be the same as the old PCT responsible population. Where local authority and PCT boundaries were not coterminous, data suppliers were asked to supply figures for the local authority responsible population if these were available.

Where data suppliers were not able to provide data for the local authority responsible population, NHS England estimated local authority figures by apportioning PCT data based on population. Details of the apportioning methodology can be found in the  report. All data received from 2016 to 2017 onwards is supplied at local authority responsible level, negating the need to use estimation.

Note that the national, regional and local statistics reported in publications prior to 2016 to 2017 were based on a local authority data set that included some estimated data (from supplied PCT data). Where this is the case, estimated figures are marked with an ‘[e]’ in the data tables which accompany those publications.

This year most of the will be sourced from the accredited official statistics reported in the annual COVER ±è³Ü²ú±ô¾±³¦²¹³Ù¾±´Ç²Ô.Ìý

Quality assurance

The following automated data validation checks are conducted by UKHSA:

• checks on data completeness (a submission is available for each UTLA)

• comparisons of the number of children vaccinated with the associated eligible population to ensure it is not higher and to explain if it is equal

• comparisons with previous quarters’ data to identify and explain any large changes in the size of the population eligible for vaccinations (greater than or equal to 20% for BCG and hepatitis B, 10% for all others) and in vaccination coverage (greater than or equal to 10 percentage points for BCG and hepatitis B; greater than or equal to 5 percentage points for all others)
• comparisons with coverage figures reported in previous quarters for the same birth cohort of children to identify any unexpected changes (more than 5 percentage point decrease in coverage; more than 10 percentage point increase in coverage; more than 20% increase in denominator)
• comparisons of the number of children vaccinated for vaccinations generally co-administered to identify any large differences (more than 10% difference); for example, Hib/MenC, the PCV booster, MMR1, and the MenB booster are often co-administered at the 12-month appointment, and the preschool booster and MMR2 are often co-administered at the 3-year 4-month appointment
• comparisons between the number of children vaccinated with primary doses and those vaccinated with secondary doses to ensure that the number vaccinated with primary doses is always higher

Potential breaches are manually reviewed and queried with local providers and NHS England local teams. This may result in amendments, exclusion of data or publication with caveats.

Confidentiality and disclosure control

The has been applied in the production of these statistics. The data is received in aggregate form from the SDCS secure file-sharing platform so a Data Protection Impact Assessment (DPIA) is not needed.

Disclosure controls have been applied according to the following:

• suppressing all data: number of children eligible, number vaccinated and coverage where the number eligible is between 1 and 5
• reporting coverage percentages as a range so the actual figure cannot be deduced

Combining eligible small populations from 2 local authorities which are reported as:

• the Isles of Scilly under Cornwall
• the City of London data under Hackney

Statistics in this report are therefore presented by 149 UTLAs for all routine vaccinations. 

Geography

Vaccination coverage and eligible population is published for each:

• country
• upper tier local authority (UTLA) within England
• regions within England
• UKHSA regions within England

Except where data is suppressed in line with our statistical disclosure control protocol.

Quality summary

Quality means that statistics fit their intended uses, are based on appropriate data and methods, and are not materially misleading.

Quality requires skilled professional judgement about collecting, preparing, analysing, and publishing statistics and data in ways that meet the needs of people who want to use the statistics.

This section assesses the statistics against the dimensions of quality.

Relevance

Relevance is the degree to which the statistics meet user needs in both coverage and content.

What are the statistics for?

These statistics are the authoritative source of figures for annual coverage data when referring to immunisation programmes at all levels within England. They can be used:

• to measure progress against the WHO recommendation that on a national basis at least 95% of children are immunised against diseases preventable by immunisation and targeted for elimination or control
• to provide evidence for JCVI recommendations
• to understand the coverage as the level of protection in the community
• by local authorities to measure their performance
• to evaluate a vaccine programme
• to identify susceptible populations
• to inform vaccine policy decisions

How do they meet user needs?

As a long-running collection using the same methods since 1987, the reports allow for comparison of national trends over time.

How do we know about user needs?

UKHSA has undertaken user engagement work with the transition to publishing the statistics at UKHSA.

Accuracy and reliability

Accuracy is the proximity between an estimate and the unknown true value. Reliability is the closeness of early estimates to subsequent estimated values.

These are established collections based on total populations rather than a sample.

COVER data is a population-based collection provided by CHISs on behalf of all 153 UTLAs.

On 1 April 2023, Cumbria local authority split into 2 new local authorities, Cumberland Local Authority and Westmorland and Furness Local Authority.

However, in the 2024 to 2025 COVER submission, a single submission representing the old Cumbria local authority was received. Therefore, 151 submissions were received, representing data from all 153 local authorities. 

Comparisons of figures over time should be considered in the context of data quality issues reported by some data suppliers in recent years. Apparent trends could reflect changes in the quality of data reported as well as real changes in vaccination coverage. While this issue will be more apparent at a local level, it will also have an impact on the national figures.

Any missing data is clearly marked within the data tables using Analysis Function standard symbols.

Timeliness and punctuality

Timeliness refers to the time gap between publication and the reference period. Punctuality refers to the gap between planned and actual publication dates.

COVER data is published on a quarterly basis and reports on children who reached 3 months (for BCG only), 12 months, 24 months or 5 years of age within the quarter being reported. This means that the data may reflect vaccinations given months or even years earlier. The quarterly data is published at the end of the subsequent quarter, for example, data for quarter 1 is published at the end of quarter 2.

The quarterly reports are official statistics and are pre-announced at least 28 days in advance. The annual reports are accredited official statistics and are pre-announced one year in advance. Provisional publication dates for the year ahead are pre-announced online and can be found on the UKHSA release calendar.

Accessibility and clarity

Accessibility is the ease with which users can access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice.

This publication includes an HTML report, ODS data tables, and an interactive dashboard. The publication includes visualisations that help explain the data. These are designed to be accessible by those with colour vision deficiency as each element has a different luminance value. This means that there is always sufficient contrast between elements for them to be distinguished. The dashboard is designed to make data more meaningful by allowing local, regional and national comparisons over time.

We comply with the and the .

We publish the main statistics report as an HTML web page in order to make the report easier to access across different devices, aligning with the accessibility features mentioned in the ÌìÃÀÓ°Ôº accessibility statement.

The supplementary data tables are published in ODS format and follow the Government Analysis Function’s . For example, each worksheet contains only one table. We also do not include nested tables with merged cells, as these do not work well with screen readers. We avoid using empty cells for the same reason.

Coherence and comparability

Coherence is the degree to which data that is derived from different sources or methods but refers to the same topic, is similar. Comparability is the degree to which data can be compared over time and domain.

Since the National Health Service Act was enacted in 1946, the UK childhood immunisation programme has undergone many changes. Changes to the childhood programme are implemented based on epidemiological assessment, medical evidence, and cost effectiveness. When there are changes to an established programme, the COVER collection is updated to maintain as much comparability over time as possible.

Disruption caused by the COVID-19 pandemic, beginning in March 2020, is likely to have caused some decreases in vaccine coverage seen in 2020 to 2021 and 2021 to 2022 compared with earlier years. In this report, the disruption affected the measures of children aged 5 years the most as some of these children would have been scheduled to receive their routine childhood immunisations from March 2020 onwards.

The statistics are presented at a national and regional level and by UTLA. Due to the different sources and methods by which the local authority data has been derived, coverage figures may not be directly comparable over time.

Outside the UK, national vaccination policies differ and countries use different methods to calculate vaccine coverage. Therefore, direct comparison with countries outside the UK is not always appropriate. However, the World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) attempt to determine the most accurate and up-to-date estimates of immunisation coverage for different countries through their joint annual reporting form submission from national experts. These estimates of national immunisation coverage are reported on the .

Information on vaccine coverage surveillance in European countries is available on the .

Uses and users

Users of statistics and data should be at the centre of statistical production, and statistics should meet user needs.

This section explains how the statistics are used, and how we understand user needs.

Appropriate use of the statistics

The statistics can be used to:

• extract the official estimates of vaccination coverage
• understand trends of vaccination coverage by UTLA over time
• compare vaccination coverage across different geographies

Known users

We are aware that the statistics have been used by the following entities, for the purposes listed:

UKHSA

• refers to the statistics as the authoritative source of figures for annual coverage data when referring to immunisation programmes at all levels within England
• uses them to report UK vaccine coverage data to the WHO and the UNICEF
• uses the report to review statistics for their local populations and compare with regional and national statistics

Department of Health and Social Care

• uses the report to inform the development and evaluation of government policy on immunisation and to assess the delivery of different immunisations in the national programme
• uses it to help inform vaccine policy decisions such as national and regional catch-up programmes for specific immunisations
• uses it to input to public and parliamentary business and input to the Public Health Outcomes Framework (PHOF)

Local authorities

• use the statistics to monitor local coverage of childhood vaccinations

NHS England

• uses to monitor local coverage of childhood vaccinations

the Organisation for Economic Co-operation and Development (OECD)

• uses the statistics in the and

User engagement

In June 2024, we carried out a user engagement survey for the quarterly COVER publications. Most users reported frequent interaction with the quarterly statistics to produce outputs relevant to their local area, to understand local coverage, and to compare with other areas and identify trends.

In February 2025, we conducted a user engagement survey for the as published by NHS England. Following initial responses, user requirement sessions were conducted with feedback incorporated into the development of the .

Related statistics

Vaccination data for Wales, Scotland and Northern Ireland are also available:

• (Public Health Scotland)

• (Public Health Agency)

• data from this report is published in the following: (public health profiles)

are available from NHS England. are available from The National Archives.

More information on data collection can be found in the COVER programme information standard and the Green Book on immunisation against infectious diseases. Further immunisation information for health professionals and immunisation practitioners is also available.

In addition to COVER, data and reports for England are available on the coverage for all vaccinations routinely offered under the national immunisation programme.

UKHSA also publishes:

• annual hepatitis B statistics
• annual statistics on the seasonal influenza vaccination programme
• quarterly health protection and communicable disease reports

The number of vaccinations that GP practices are paid for administering (not coverage data) is published by NHS England in .

Appendix A. COVER annual and quarterly reports

Annual reports

Financial year (FY) 2024 to 2025

Data quality issues were identified for 14 UTLAs in London relating to cleaning and extraction of data from GP systems, particularly relating to children not registered with a GP. As a result, only children registered with a GP are included until the data on unregistered children can be validated. Coverage in these UTLAs is overestimated as coverage is likely to be higher among the registered-only population compared to the population not registered with a GP. The 14 UTLAs affected are: Greenwich, Hammersmith and Fulham, Kensington and Chelsea, Lambeth, Lewisham, Southwark, Westminster, Bexley, Brent, Bromley, Ealing, Harrow, Hillingdon, and Hounslow.

FY 2023 to 2024

BCG vaccination coverage

Bacillus Calmette–Guérin (BCG) is a selective vaccination.

In FY 2022 to 2023, BCG vaccination coverage was assessed at age 3 months. FY 2022 to 2023 was the first time data has been recorded for the 3-month cohort, it was badged as statistics in development.

In FY 2023 to 2024, BCG vaccination data is also available for age 12 months.

Eligible populations and number vaccinated were recorded for each local authority in England. Therefore, it is possible to publish national and region coverage values for this vaccination.

In previous years, data collected at age 12 months only contained the number vaccinated, so national coverage had not previously been reported.

COVID-19

Disruption caused by the COVID-19 pandemic, beginning in March 2020, is likely to have caused some of the decreases in vaccine coverage seen in FY 2020 to 2021 and FY 2021 to 2022, compared with earlier years. In this report, the effect of COVID disruption is most likely to be seen in the 5-year age group, where some children would have been scheduled to receive their routine childhood immunisations from March 2020 onwards.

Furthermore, some children who may have missed out on receiving routine immunisations at the scheduled time, and otherwise would have caught up by their fifth birthday, may also have been impacted by the COVID-19 pandemic from late March 2020 onwards.

Changes to the COVER data collection

Changes to the COVER collection form were made by UKHSA (then Public Health England) from April 2013 to enable collection by local authority. The data collection form has also been subject to amendments to reflect changes to the routine schedule when vaccines have been added, amended or withdrawn.

Statistics on the number of persons receiving BCG vaccinations were previously published in this bulletin until the was suspended following a review in 2013. Neonatal BCG coverage data is now collected as part of the COVER programme in accordance with an updated COVER (ISN) published in November 2014. Data on BCG vaccination coverage is published, along with hepatitis B data, in the ‘Selective neonatal vaccination programmes’ section of the main report. Subsequent updates to the ISN were made in November 2017, April 2019 and February 2020.

FY 2022 to 2023

No significant data quality issues were reported for FY 2022 to 2023 data. BCG 12-month coverage data was unavailable for FY 2022 to 2023 and not included in that year’s report. BCG 3-month coverage data was reported for the first time in FY 2022 to 2023, it was designated as official statistics in development.

FY 2021 to 2022

Data for the Peterborough Local Authority showed unusual variation in FY 2021 to 2022, with coverage thought to be underestimated.

Among vaccinations due by the child’s first birthday, FY 2021 to 2022 coverage  for Peterborough decreased from FY 2020 to 2021 coverage by between 6.1 and 6.3 percentage points.  Among vaccinations due by the child’s second birthday, the corresponding change was a decrease of between 7.1 and 8.5 percentage points, and among vaccinations due by the child’s fifth birthday, the corresponding change was a decrease of between 7.4 and 8.2 percentage points.

Between FY 2020 to 2021 and FY 2021 to 2022, Peterborough population denominator data increased (by 6.6% among children aged 1 year, by 4.5% among children aged 2 years and by 4.1% among children aged 5 years). This was in contrast with the changes in the corresponding population denominators for East of England region, which decreased over the same period (by 3.4% among children aged 1 year, by 1.0% among children aged 2 years and by 1.2% among children aged 5 years).

At England level, there were also denominator decreases over the same period (3.7% among children aged 1 year, 1.8% among children aged 2 years and 1.0% among children aged 5 years).

This is thought to be related to a data migration issue, where a batch of individuals were registered but vaccination data was unavailable. This data could not be separated from the overall submission for Peterborough, so is included. The effect of this is that FY 2021 to 2022 coverage rates for Peterborough are lower than they otherwise would be across all age cohorts and all vaccines, and substantially lower than FY 2020 to 2021 coverage rates, which were unaffected by the data quality issue.

FY 2020 to 2021

During FY 2020 to 2021, Southern Health Care NHS Trust took over as provider for 4 local authorities in the South East region: Southampton, Portsmouth, Hampshire, and the Isle of Wight.

Quarterly reports

FY 2024 to 2025

Data quality issues were identified for 14 UTLAs in London relating to cleaning and extraction of data from GP systems, particularly relating to children not registered with a GP. As a result, the methodology was changed and validated, and data for quarters 1 and 2 were re-published so that quarters 1 to 4 use the same methodology. Only children registered with a GP are included until the data on unregistered children can be validated.

The 14 UTLAs for which data has been updated are: Greenwich, Hammersmith and Fulham, Kensington and Chelsea, Lambeth, Lewisham, Southwark, Westminster, Bexley, Brent, Bromley, Ealing, Harrow, Hillingdon, and Hounslow.

As a result, a sharp drop in coverage across all antigens from quarter 4 2023 to 2024 and quarter 1 2024 to 2025 should be considered in this context and may be partially due to improved data quality.

FY 2018 to 2019

Data quality issues relating to complexities in data flows between providers and CHISs were reported in London data in 2018 to 2019. This is attributed to the data improvement work that is occurring due to the wider digital strategy being implemented. Changes in vaccine coverage within London in 2018 to 2019 should be considered in the context of changing data sources, in that changes in coverage may be in part due to changes in data source

FY 2017 to 2018

Data quality issues in some London COVER returns during 2017 to 2018 were observed as new hubs became responsible for generating coverage data. Changes in vaccine coverage within London for that year should be considered in the context of changing data sources, in that changes in coverage may be in part due to changes in data source.