The Needle Exchange Surveillance Initiative (NESI): Everything you ever wanted to know about NESI (but were afraid to ask)
The Needle Exchange Surveillance Initiative (NESI): Everything you ever wanted to know about NESI (but were afraid to ask)
By Norah Palmateer August 2024
Reader in Public Health at Glasgow Caledonian University, Honorary Healthcare Scientist at Public Health Scotland, and manager of the 2022-23 NESI survey
Yesterday marked the publication of the report from the 8th iteration (or “sweep” as we usually call it) of the Needle Exchange Surveillance Initiative (NESI), which was carried out from November 2022 to December 2023. NESI is a national “bio-behavioural” survey of people who inject drugs (PWID), so-called because it collects information on people’s self-reported behaviour via a questionnaire and collects biological information via a blood spot (which is obtained via a finger-prick device and later tested for blood-borne viruses). Participants are recruited from needle exchange sites across the country.
Rather than go into detail on the latest findings of the report, I’m going to explain what NESI is about, what it is used for and a bit about what happens behind the scenes.
Why NESI?
NESI recruits a representative sample of PWID attending low threshold services for injecting equipment and other harm reduction interventions. In other words, it is a snapshot that can be used to make inferences about the whole population of PWID. NESI is one of only a few national studies of its kind worldwide – the others are in England, Canada and Australia.
Something for everyone
NESI is sometimes referred to as “public health surveillance” and sometimes as a “research study” – it is both. NESI has provided routine surveillance on the prevalence of blood-borne viruses among PWID. For example, it has allowed us to see how levels of hepatitis c virus (HCV) infection have changed with the scale up of effective treatments and it also allowed us to quantify the scale of the HIV outbreak among PWID in Glasgow city. On the research front – by examining the relationships between the different items of information collected – we can answer lots of other questions; for example, what factors contributed to the HIV outbreak? How did prison hepatitis B (HBV) vaccination affect HBV infection among PWID? Is benzodiazepine use associated with non-fatal overdose? And many more. (For those interested, a list of research publications using NESI data is listed in an appendix to the report).
As with all publications, we have to distil the findings into ‘key points’, which is always tricky to do for NESI findings because they cover so many themes and are so wide-ranging. But that is also the beauty of NESI. At the beginning, it was motivated primarily by the need to understand the prevalence of HCV, and later HIV, among PWID, but it is not just about blood-borne viruses. NESI also measures other drug harms, such as soft tissue infections and non-fatal overdose, and uptake of interventions, such as hepatitis B vaccination, HCV/HIV testing and treatment, opioid agonist therapy, naloxone and sterile injecting equipment. More recent additions include questions to gauge quality of life and experiences of stigma. NESI can easily pivot to address emerging public health issues by adding new questions like we have done recently for drug consumption rooms and drug testing (or indeed sometimes additional tests on the blood spots, where the residual blood is sufficient and the technology available).
Going forward, NESI is going to be key in assessing progress on Scottish Government strategies, such as targets on Hepatitis C elimination, HIV transmission elimination, the National Mission on drug deaths and MAT Standards.
Behind the scenes
For those involved in NESI, the publication of the report is the culmination of approximately 20 months of hard work – including 13 months of fieldwork (it takes at least a year to cover all of the mainland NHS Boards), followed by 7 months of data entry, data analysis, report writing, and data visualisation (and that is just for the latest sweep).
It is very much a team effort and the number of people who have been involved in making NESI a success over the years is sizeable. I first became involved in NESI in an analytical/scientific capacity back in 2008, but my most recent role was managing the 2022-23 survey sweep. Andy McAuley, Alison Munro and Liz Allen have held this role before me (and I have a newfound respect for the multi-tasking required). Sharon Hutchinson, CBE, is the current Principal Investigator of the study. Sharon, along with David Goldberg and Avril Taylor, originally conceived of the study, secured funding, and have been its biggest champions. The study also wouldn’t happen without a dedicated team of interviewers who travel near and far to all of the services to recruit participants, laboratory colleagues, our trusty Research Programme Advisor Chris Biggam, analytical support, the pharmacies and agencies that host our interviewers, and NHS Board personnel who facilitate access to these places. Last but not least are the participants, who generously provide their time and information to NESI.
The latest report, data tables and an infographic can be found at the link below. Happy reading!
