UK Register of HIV seroconverters

An observational study of HIV positive people whose date of infection is known

What was this study about?

The UK Register is a national cohort of individuals whose time of HIV seroconversion can be reliably estimated. Set-up in 1994, the initial aim was to better understand the natural history of HIV by assessing the time from HIV infection (seroconversion) to AIDS and death and associated factors impacting on survival.

Current aims of the cohort include assessment of temporal changes in the time from HIV seroconversion to AIDS and death (i.e. effectiveness of therapy), examination of the effect of time since infection on virological, immunological and clinical response to therapy, assessment of the prevalence of transmitted drug resistant HIV and its long-term consequences, and identification of genetic characteristics that account for differences in progression of HIV disease and response to drug therapy.

The UK Register is the only multi-centre study monitoring the HIV epidemic in the UK from the time of infection, providing key information that can be translated into sensitive health policies and national guidelines for the clinical management of HIV.

The study is also part of an international collaboration of 23 similar cohorts known as CASCADE, making an important contribution to produce scientific evidence for global HIV policy stakeholders.

What difference did this study make?

We have been able to monitor the changing patterns of drug resistance in people newly infected with HIV in the UK. Several articles have been published. One of the highlights is the data published in 2017. This indicated that transmitted drug resistance in the MSM population remained very low, and rates remained stable in those with heterosexually acquired HIV infection. Resistance to currently recommended first-line antiretroviral therapy, including integrase inhibitors, remained reassuringly low.


This study has now moved to the Institute for Global Health.

Type of study

Observational study

Contact details

Who funded the study?

The Medical Research Council.

When did it take place?

This study is an ongoing cohort launched in 1994 and is currently incorporated into core activities of the Clinical Trials Unit.

Where did it take place?

Over 100 NHS clinics providing healthcare to HIV infected people across the UK.

Who was included?

Patients are eligible for this study if they are:

 16 years or older at the time of their first HIV antibody positive test for those with horizontal acquired HIV infection or at enrolment into the study for those with perinatal infection confirmed by laboratory evidence of seroconversion by at least one of following criteria:        

-- HIV positive antibody test within 12 months of an HIV negative antibody test

-- HIV antibody negative with positive RT-PCR Test “incident” using a RITA (recent incident testing algorithm) assay

-- Equivocal HIV antibody test supported by a repeat test within a 2-week period showing a rising optical density

-- Have clinical manifestations of symptomatic HIV seroconversion illness supported by antigen positivity and <4 bands positive on Western Blot

-- Reported to the CHIPS<link to CHIPS study> cohort or received paediatric HIV care in