Corporate report

Number of animals used: 2024

Updated 25 September 2025

Our primary duty is to protect the public’s health from infectious disease and other health hazards. The vast majority of our scientific research does not involve animals but the biological similarities between humans and other species mean that they can, on some occasions, be the only effective model for research into infectious diseases and other health impacts where the response to infection, vaccination or environmental hazards is too complex to be modelled in any other way. Animals are only used where there is no viable alternative.

Together with over 130 organisations and universities, we have signed up to the Concordat on Openness in Animal Research in recognition of the important work we undertake that involves animals. At the UK Health Security Agency (UKHSA) we are committed to the refinement, reduction and replacement of animals in research, and continually develop and implement new enrichment methods, make refinements to procedures to reduce harms, look to reduce animal numbers, and develop and use alternative cell and microfluidic models wherever possible.

The following tables provide the numbers of animals used, per species, at our scientific campuses at Porton, Colindale and Chilton, in 2024.

Table 1a. Annual return figures 2024: UKHSA Porton

Severity	NHP	Mice	Guinea pigs	Hamsters	Ferrets	Rats	Cotton rats	Rabbits
Non Recovery	8	0	0	0	0	0	0	0
Mild	20	514	127	177	64	18	36	0
Moderate	20	1	4	185	31	0	0	0
Severe	0	87	1	72	0	0	0	0
Total	48	602	132	434	95	18	36	0

Table 1b. Annual return figures 2024: Porton Biopharma Limited (PBL)

Severity	NHP	Mice	Guinea pigs	Hamsters	Ferrets	Rats	Cotton rats	Rabbits
Mild	0	0	0	0	0	0	0	6
Moderate	0	0	122	0	0	0	0	0
Severe	0	0	286	0	0	0	0	0
Total	0	0	408	0	0	0	0	6

Porton

Research activities included the development of drugs and vaccines against a wide range of potential viral and bacterial threats. This activity has provided a rare capability to national and international funders and gives assurance to the public and government that when a new infectious disease threat emerges, UKHSA is well rehearsed in assisting in the development of new countermeasures to protect the population. 

Coronaviruses

Small rodent non-lethal disease models were used to assess the efficacy of a range of candidate clinical prophylactics and treatments for disease cause by coronaviruses. This model was also used to assess:

• the risk of increased disease from newly emerging variants of concern
• the potential for immune escape from immunity elicited by vaccines
• prior exposure to earlier circulating COVID-19 variants of concern (convalescence)

The model has been subject to additional development to allow a deeper understanding of the contributions different elements of the immune system make to vaccine protection, as well as the assessment of vaccines that provide broader protection against SARS-CoV-2 variants and other coronaviruses. Development of non-lethal models for MERS-CoV has been carried out using hamsters and non-human primates (NHPs). These models are important for assessing broadly protective beta coronavirus vaccines.

Respiratory syncytial virus (RSV)

RSV is a primary cause of hospital admission in infants due to severe breathing difficulties. Development of a non-lethal cotton rat model has sought to support vaccine developers in the evaluate the safety and efficacy of RSV vaccines. Preclinical models are particularly important for RSV vaccine development to identify vaccines that cause harm by inducing enhanced disease.

Influenza

The inherent and ever-present risk of a re-assorted influenza virus emerging from within the animal kingdom remains a concern for a future influenza pandemic. The 20th and early 21st century have seen influenza pandemics involving ‘seasonal’ influenza viruses in 1918, 1957, 1968, 1977 and 2009. While the last of these ‒ the so-called ‘swine influenza’ pandemic ‒ was relatively mild, this cannot be assumed for a future emerging virus. Added to this, the threat of a pandemic caused by highly pathogenic avian influenza (HPAI) viruses continues to be of great concern as the number of species that can be infected increases leading to the possibility of sustained human-to-human transmission coupled with the clinical observation that HPAI tend to present as much more clinically severe than the so-called seasonal influenza strains. UKHSA has therefore developed small animal models of HPAI in order to assess countermeasures. 

UKHSA is appointed as an Outside Testing Laboratory for AstraZeneca which conducts vaccine release testing. In brief, the ferret non-lethal disease model of influenza has been used under Good Manufacturing Practice (GMP) quality standards to safety test the live attenuated influenza vaccine (LAIV) produced by Astra Zeneca. LAIV has been used in the UK since 2013 to protect children against infection with influenza. The vaccine is the preferred product for children in flu ‘at-risk’ groups aged from 2 to 17 years (inclusive) and is used as part of the Department of Health and Social Care’s routine children’s vaccine programme delivered in schools and general practices. The licence has also been used for supporting activities around assessing the vaccine effectiveness of LAIV, including optimising the ferret model for clinical translatability. 

Publication

Schewe KE, Cooper S, Crowe J, Llewellyn S, Ritter L, Ryan KA, Dibben O ‘An optimised live attenuated influenza vaccine ferret efficacy model successfully translates H1N1 clinical data’ Vaccines 2024: volume 12, issue 11, article 1,275

Tuberculosis

Guinea pig and mouse studies

Drug-resistant tuberculosis (TB) is a major contributor to antimicrobial resistance worldwide, and year-on-year continues to be a public health threat. Half a million people become ill with drug-resistant TB every year. Patients who are infected with strains resistant to isoniazid and rifampicin, called multidrug-resistant (MDR) TB, are practically incurable by standard first-line treatment. The TB research community is working collaboratively to ensure that TB does not once again become an incurable disease. UKHSA is working with TB drug and vaccine developers within the global research community, by evaluating the efficacy of new and novel drug compounds and vaccines in our optimised in vivo models. This ensures that the most safe and promising drug and vaccine candidates progress through to clinical trials in humans.

Macaque studies

Work has been performed to support the global effort to combat tuberculosis. Studies using the non-human primate (macaque) models of Mycobacterium tuberculosis (M. tuberculosis) infection have supported the clinical development of new TB vaccine candidates and new TB drugs and provided data to inform their further development for clinical deployment. To assist efforts to identify biomarkers of disease progression and correlates of risk and protection that could revolutionize the development of new interventions, detailed immune profiling of responses induced by vaccination, treatment and Mycobacterium tuberculosis infection have been conducted.

Publications

1. Peralta Alvarez MP, Downward K, White A, Redondo Azema H, Sibley L, Sarfas C, Morrison A, Dennis M, Diaz Santana D, Harris SA, Li S, Puentes E, Aguilo N, Martin C, Sharpe S, McShane H, Tanner R ‘MTBVAC induces superior antibody titers and IgG avidity compared to BCG vaccination in non-human primates’ NPJ Vaccines 2024: volume 9, issue 1, article 230

2. Peralta Alvarez MP, Jones H, Redondo Azema H, Davis C, White AD, Sarfas C, Dennis M, Li S, Wright D, Puentes E, Kimuda S, Belij Rammerstorfer S, Aguilo N, Martin C, Sharpe S, McShane H, Tanner R ‘Low dose M.tb infection but not BCG or MTBVAC vaccination enhances heterologous antibody titres in non-human primates’ Frontiers in Immunology 2024: volume 15, article 1387454

3. Voogd L, van Wolfswinkel M, Satti I, White AD, Dijkman K, Gela A, van Meijgaarden KE, Franken KLMC, Marshall JL, Ottenhoff THM, Scriba TJ, McShane H, Sharpe SA, Verreck FAW, Joosten SA ‘Mtb specific HLA E restricted T cells are induced during Mtb infection but not after BCG administration in non-human primates and humans’ Vaccines 2024: volume 12, issue 10, article 1,129

4. Voogd L, van Wolfswinkel M, Satti I, White AD, Dijkman K, Gela A, van Meijgaarden KE, Franken KLMC, Marshall JL, Ottenhoff THM, Scriba TJ, McShane H, Sharpe SA, Verreck FAW, Joosten SA ‘Mtb specific HLA E restricted T cells are induced during Mtb infection but not after BCG administration in non-human primates and humans’ bioRxiv preprint 2024: article 2024.08.26.609630

5. Sibley L, Sarfas C, Morrison AL, Williams J, Gkolfinos K, Mabbutt A, Eckworth W, Lawrence S, Dennis M, White A, Sharpe S ‘Immune cell population dynamics following neonatal BCG vaccination and aerosol BCG revaccination in rhesus macaques’ Scientific Reports 2024: volume 14, issue 1, article 16,993

6. Peralta Alvarez MP, Downward K, White A, Harris SA, Satti I, Li S, Morrison A, Sibley L, Sarfas C, Dennis M, Azema HR, Sharpe S, McShane H, Tanner R ‘Intravenous BCG vaccination in non-human primates induces superior serum antibody titers with enhanced avidity and opsonizing capacity compared to the intradermal route’ Vaccine 2024: volume 42, issue 26, article 126,444

Arbo and robovirus pathogens

2024 was a successful year for developing understanding in in vivo disease models that will be invaluable in future therapy efficacy studies and reducing disease burden in low- and middle-income countries (LMICs). During 2024, studies were conducted for several pathogens of high disease consequence. New model development for emerging and re-emerging pathogens such as Nipah and mpox were established in rodent species. Additionally, immunogenicity and efficacy trials highlighted potential new therapies and vaccines to be progressed against Nipah and Crimean-Congo Haemorrhagic Fever (CCHF) disease. Furthermore, immunogenicity studies for potential viral vector vaccines were performed to determine the effects of prior vector immunity.

Publications

1. Findlay-Wilson S, Thakur N, Crossley L, Easterbrook L, Salguero FJ, Ruedas-Torres I, Fotheringham S, Kennedy E, Bailey D, Dowall S ‘Cross-protectivity of henipavirus soluble glycoprotein in an in vivo model of Nipah virus disease’ Frontiers in Immunology 2025: volume 16, article 1,517,244

2. Ruedas-Torres I, Findlay-Wilson S, Kennedy E, Dowall S, Salguero FJ ‘Pathology and host-pathogen interactions in a golden Syrian hamster model of Nipah virus infection’ Frontiers in Veterinary Science 2025: volume 12, article 1,518,358

3. Kempster S, Hassall M, Graham V, Kennedy E, Findlay-Wilson S, Salguero FJ, Bagci B, Elaldi N, Oz M, Tasseten T, Charlton FW, Barr JN, Fontana J, Duru C, Ezeajughi E, Matejtschuk P, Arnold U, Adedeji Y, Mirazimi A, Hewson R, Dowall S, Almond N ‘Convalescent human plasma candidate reference materials protect against Crimean-Congo haemorrhagic fever virus (CCHFV) challenge in an A129 mouse model’ Virus Research 2024: volume 346, article 199,409

4. Ebisine K, Quist D, Findlay-Wilson S, Kennedy E, Dowall S ‘A review of nonhuman primate models of Rift Valley Fever Virus infection: progress, challenge strains, and future directions’ Pathogens 2024: volume 13, issue 10, article 856

5. Graham VA, Easterbrook L, Rayner E, Findlay-Wilson S, Flett L, Kennedy E, Fotheringham S, Kempster S, Almond N, Dowall S ‘Comparison of Chikungunya virus-induced disease progression and pathogenesis in type-I interferon receptor-deficient mice (A129) and 2 wild-type (129Sv/Ev and C57BL/6) mouse strains’ Viruses 2024: volume 16, issue 10, article 1,534

Developing replacement methods

In 2024, 8 macaques were used under non-recovery procedures to provide tissues for the development of organ-on-a-chip culture methods that will replace and reduce animal use, to provide data on the influence of the gut microbiome on disease progression and on vaccine efficacy, and tissue and blood samples for critical naive controls for variety of immunological assays for vaccine and/or therapeutic studies.

Bacterial pathogens

Yersinia plague, caused by the bacterium Yersinia pestis, is estimated to have been responsible for a least 200 million deaths throughout recorded human history. Pneumonic plague poses a particular concern to human health, as successful treatment depends on the rapid administration of antibiotic treatment. Mice have been used as an effective disease model to evaluate the efficacy of medical interventions against aerosolised Yersinia pestis. At UKHSA, we are collaborating with vaccine developers and the wider research community to assess the performance of new and novel vaccine candidates using our optimised in vivo models. This work helps to ensure that the safest and most promising vaccines advance to clinical development.

Pseudomonas aeruginosa is a highly adaptable opportunistic bacterial pathogen. Although it rarely causes illness in healthy individuals, it can lead to a wide range of serious infections in those with weakened immune systems, particularly in a healthcare setting. Those at highest risk include cancer patients, newborns, and individuals with severe burns, diabetes mellitus or cystic fibrosis. Pseudomonas aeruginosa exhibits intrinsic resistance to many antibiotics and has a notable capacity to acquire new resistance, making treatment increasingly difficult. UKHSA has developed mouse models to represent chronic infection which, in collaboration with academic and industrial partners, will be used to assess the efficacy of new drugs, vaccines and therapeutics.

Porton Biopharma Limited (PBL)

PBL’s work is focussed on quality-assured development of life-saving biopharmaceuticals. We manufacture the licenced product Erwinase, a childhood leukaemia therapy, and the UK’s licenced anthrax vaccine. As part of the licence there is a requirement to undertake a limited number of animal tests to ensure that each batch of the vaccine is safe and effective. This involves guinea pigs and rabbits. We continue to meet our commitment to the licence, ensuring each batch of our vaccine is safe and effective.

Table 2. Annual return figures 2024: UKHSA Colindale

Severity	NHP	Mice	Guinea pigs	Hamsters	Ferrets	Rats	Cotton rats	Turkeys
Non recovery	0	0	53	0	0	0	0	0
Mild	0	2	0	0	5	0	0	24
Moderate	0	0	0	0	0	0	0	0
Severe	0	2	0	0	0	0	0	0
Total	0	4	53	0	5	0	0	24

Colindale

Guinea pigs

In 2024, a total of 53 guinea pigs were utilised. For flu H3 subtype assays we employ guinea pig red blood cells, and in serological studies we utilise these red blood cells to assess the immune response levels in humans. The severity was categorised as non-recovery.

Mice

A total of 4 mice were utilised in 2 tests (primary and neutralisation) to identify bacterial toxins (Clostridium botulinum). These tests are conducted using clinical samples or food associated with patients who are suspected of having contracted the bacteria. Two of the mice were found to be affected, testing positive, which is classified as severe. The mice used for the anti-toxin neutralisation exhibited only mild severity, as anticipated.

Turkeys

To conduct influenza assays, 24 turkeys were utilised to supply normal red blood cells. The actual severity was classified as mild.

Ferrets

In total, 5 ferrets were utilised to produce antisera against new and emerging influenza strains, contributing to the development of flu vaccines in the UK. The actual severity was classified as mild.

Table 3. Annual return figures 2024: UKHSA Chilton

Severity	NHP	Mice	Guinea pigs	Hamsters	Ferrets	Rats	Cotton rats	Turkeys
Non recovery	0	0	0	0	0	0	0	0
Mild	0	40	0	0	0	0	0	0
Moderate	0	98	0	0	0	0	0	0
Severe	0	0	0	0	0	0	0	0
Total	0	138	0	0	0	0	0	0

Chilton

Radiation-induced intestinal carcinogenesis

Animal studies are crucial to support those monitoring humans exposed to radiation in order to continually improve the scientific understanding that underpins effective radiation protection. Current uncertainties include the risks posed by low doses of radiation, and whether age, genetic factors and/or underlying disorders increase susceptibility to radiation-induced diseases.

In total, 138 mice were used to investigate the effects of age and human-relevant genetic mutations increasing colon tumour formation on the susceptibility to radiation-induced colon cancer. The complex processes by which radiation leads to cancer development cannot currently be fully modelled in non-animal systems, with mouse models providing essential human-relevant data.

A total of 29% (40) of these mice suffered mild or no harm and 71% (98) suffered moderate harm. The mild and moderate harms were predominantly due to colon tumour development and include lack of appetite, weight loss, rectal bleeding or swelling. Some (less than 5%) female mice of the strain used can also develop mammary tumours in older age (not related to radiation). All mice were closely monitored for signs of disease and weighed frequently, and any animals were humanely killed before their experimental time point if they lost 20% of their body weight, demonstrated rectal bleeding that did not resolve within 48 hours or a rectal swelling that did not resolve within 12 hours, developed a mammary tumour, or showed signs of poor health. A total of 9% (13) of the total number of mice were humanely killed before their experimental time point, 7 due to rectal bleeding or swelling, 3 due to mammary tumours, 1 due to weight loss and signs of poor health and 2 due to single housing issues when their cage mate was humanely killed as a result of illness.

The results achieved will further contribute to the evidence base used by international organisations ‒ such as the International Commission on Radiological Protection (ICRP), the International Atomic Energy Authority (IAEA) ‒ relevant government agencies (such as the Department of Health and Social Care), and the nuclear industry to refine models for cancer risk estimation in human populations and improve radiation protection advice and guidance.

An additional 77 animals were used as part of research studies that did not undergo any procedures. While these animals are not required to be reported in the annual number of procedures, we believe it is important to recognise their important contribution to our work. Twenty-four of these additional animals were used for breeding, producing animals for the research studies, and were killed after the required numbers of offspring were met. Twenty-one were kept as cage mates to research animals to maintain appropriate group housing for social animals such as mice. Thirteen of these 21 were also used to provide tissues including brain, spinal cord, liver and adipose tissue for other research projects, maximising the use of these animals and preventing the use of additional animals for tissue harvesting. The remaining 32 were killed at weaning because they did not have the required genetics for inclusion in the research study. Unfortunately, due to the way genes are inherited, there will be some animals that do not have the required genetics and so are not used in the study. We keep this to a minimum by developing and using efficient breeding methods.