Main messages from the Unlinked Anonymous Monitoring (UAM) survey of people who inject drugs (PWID) in England, Wales, and Northern Ireland (EWNI) for the period 2013 to 2022 are listed below.

• Recruitment to the UAM survey in 2022 has recovered to pre-pandemic levels.
• From 2013 to 2022, the median age of UAM participants increased from 36 to 43 years, indicating an ageing group of PWID. Concurrently, the proportion of young injectors (under 25 years) decreased from 6% in 2013 to 1.5% in 2022. While this is reflective of the changing demographics of the wider injecting population, further work needs to be done to compare the UAM survey participants to other behavioural and risk factor data from the wider injecting population.
• HIV prevalence among UAM survey participants has remained low and stable over the past decade ranging from 0.8% to 1.5%. However, prevalence varies by nation and region of England.
• Overall, chronic hepatitis C (hepatitis C ribonucleic acid (RNA) and antibody positive) prevalence continues to decline from 49% in 2017 to 23% in 2022. This decline is noted alongside the scale-up of direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) in this population. However, decreases in chronic HCV prevalence are not similar across all nations and regions of England.
• There is no evidence to suggest a decline in chronic HCV prevalence among people who have recently started injecting drugs (up to 3 years prior to survey participation), which implies prevention of new and re-infections remains a challenge.
• Overall, the proportion of UAM survey participants with HCV antibodies (a marker of ever HCV infection) has increased significantly over the past decade (from 49% in 2013 to 54% in 2022) and is higher in the older cohort. This suggests continued exposure to HCV and a treatment effect, with increased uptake of HCV treatment resulting in those recruited to the UAM who are ever-infected living longer.
• Among UAM survey participants recruited in Northern Ireland, HIV and HCV antibody prevalence has increased during 2020 to 2022, to 3.8% and 48% respectively in 2022, which is reflective of an ongoing outbreak in the country.
• The proportion of participants testing positive for HCV antibodies who were aware of their infection, had seen a specialist nurse or doctor (hepatologist) for their HCV and reported having been offered and accepted treatment, increased from 30% in 2017 to 70% in 2022. Among those who were aware of their infection and had been treated, 14% reported having been infected with HCV more than once.
• Over the past decade, the percentage of participants reporting a recent (current or past year) HCV diagnostic test rose from 35% in 2013 to 48% in 2022. However, awareness of infection among those who remain infected remains low.
• The prevalence of antibodies to hepatitis B virus (HBV) core antigen (anti-HBc) (a marker of ever infection) declined significantly from 16% in 2013 to 7.8% in 2022, indicating fewer people have ever been infected with HBV. However, self-reported HBV vaccination uptake has declined over the past decade from 72% in 2013 to 61% in 2022, suggesting that PWID remain at risk of HBV infection. In 2022, HBV vaccine uptake was particularly low among those aged under 25 years (27%) and people who have recently started injecting drugs (39%).
• Significant increases in injecting risk behaviours were noted in 2022 when compared to a decade ago. Direct sharing of injecting equipment has increased from 16% in 2013 to 19% in 2022. Although 82% of all PWID in the UAM survey reported that they had accessed a needle exchange in 2022, this is a notable decline from the 90% reported pre COVID-19 pandemic.
• In 2022, nearly a quarter of those who had injected drugs in the past year reported experiencing a non-fatal overdose during that year, an increase from 16% in 2013. The increase in non-fatal overdose was noted particularly in people aged 25 and over and was similar among participants regardless of whether they had been in drug treatment previously.
• The percentage of participants carrying naloxone in the past year rose significantly, from 54% in 2017 to 68% in 2022. Moreover, 59% of those who reported overdosing in the previous year had naloxone administered, an increase from 46% in 2013.
• In 2022, heroin was the most commonly injected drug, at 92% among people who had injected in the preceding 4 weeks, followed by crack cocaine at 55%, a figure that is similar to the 2018 peak at 60% and an increase from 37% in 2013.
• The injection of other forms of cocaine significantly increased from 6.9% in 2013 to 29% in 2022 among people who had injected in the preceding 4 weeks. In Northern Ireland, reported recent injection of powdered cocaine surged from 5.9% in 2018 to a remarkable 84% in 2022.