(Science|Business) Data Corner: animal use in science declines in 2023, but not evenly

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The use of animals in research declined by 4.7% between 2022 and 2023, to 8.1 million procedures in the EU and Norway, according to European Commission data. This decline was driven mainly by reduced uses for routine production of antibodies and basic research. Uses for regulatory purposes also recorded a drop, but not in all sectors.

In 2023, 36.7% of procedures were carried out for translational and applied research, particularly on animal nutrition, welfare disorders and diseases, while 34.4% were for basic research activities, most of which focused on the nervous and immune systems and oncology. Thirteen per cent of procedures helped meet market regulations, 5.3% were dedicated to the routine production of antibodies, and 10.6% fed into other categories ranging from species preservation to forensic enquiries.

The regulatory uses of animals cover procedures to comply with the requirements set by specific sector legislations to place and maintain products on the market. This includes quality control and toxicity testing, be it for medicinal products, plant protection or food contact material. These accounted for 1.1 million uses, down 4.6% from 2022. 

All legislations reported a decrease in animal use except for industrial chemicals, which rose by 14.9%.

“This increase does not seem to stem from additional information requirements or an increase in chemicals coming to market,” the Commission report reads. Instead, it says that it may be due to its efforts in 2018 to solve data gaps in 66,000 dossiers registered under the Reach law for chemical safety and compliance, which led to further testing requests.

Europe started work on reducing animal use in research in the 1980s, but progress has been slow. The Commission banned animal testing for cosmetics in 2013, and planned to publish a roadmap to phase out animal testing for chemical safety assessments by the first quarter of 2026 at the latest. This deadline has now passed.

Meanwhile, a 2010 EU directive requires that all scientific activities be classified based on the estimated levels of pain, suffering, distress and lasting harm inflicted to live animals, namely mild, moderate, severe and non-recovery.

The number of severe uses fell to 703,461, or 8.7% of all uses in 2023. These made up 37.4% of uses for basic research, 35.1% for transnational and applied research, 19.9% for regulatory procedures and 5.4% for routine production. The highest number of severe uses was recorded for translational and applied research into animal diseases and disorders, followed by basic research on the nervous system and batch potency testing for regulatory uses.

The number of animals used in scientific experiments for the first time declined by 4.9% to 8 million in 2023, due in large part to a decrease in the use of mammals, especially mice and rats. After consecutive increases in 2021 and 2022, the first uses of primates saw an overall drop of 24.1%, across all species except rhesus monkeys. The Commission deems this “a welcome development, although it is too soon to consider this decrease a consistent long-term trend.” The use of vervets, a monkey species native to sub-Saharan Africa, dropped to zero.

On the other hand, the Commission recorded a 9% increase in first-time uses of fish, starting with salmon, trout, char, grayling and sea bass. For cephalopods, such as squid and octopus, this number rose by 163.6%, but from a low base so that it constitutes just 0.1% of all uses.

In accordance with the “three Rs” principle, which mandates researchers to replace animal tests with non-animal alternatives, reduce the number of animals used in experiments and refine procedures to minimise pain, reusing animals is permitted only when it does not result in their poor welfare. In 2023, it mostly pertained to regulatory procedures, led by skin irritation and corrosion and pyrogenicity testing. Primates were reused more often than other species.  

Under the EU directive, the reuse of an animal in a procedure classified as severe is not allowed. 

“However, in some cases, even if the procedure has been prospectively classified in a lower severity category, an individual animal may reach the ‘severe’ category due to unforeseen events occurring during the procedure,” the Commission says. 

In 2023, 326 such cases were reported, down from 662 in 2022, and “should be investigated by the authorities,” it writes. “If such events do recur, this may suggest a need to revise the prospective classification in the future.”