News / Features
EuroCoord study suggests HIV has increased in virulence and transmissibility over time
A study by the CASCADE Collaboration in EuroCoord strongly suggest that HIV, at least in Europe, has increased in virulence and transmissibility since the virus became widespread in the human population at the end of the 1970s.
HIV is a virus with high genetic diversity. As the HIV virus replicates, slight variations in the genetic structure of the virus begin to occur. Over time, this means that there will be several subtypes of HIV, and each subtype may be more or less able to cause disease. The term used to describe a pathogenís ability to cause disease is virulence, so if someone is infected with a more virulent form of HIV, they will become ill more quickly. Additionally, more virulent forms of HIV may increase the risk of transmission to others.
EuroCoord data from 15,875 HIV-positive individuals living in different settings across Europe and beyond were used to measure the changes in HIV virulence over time. To do so, the researchers looked at specific points in HIV infection before the beginning of treatment for each patient, including:
- Each patientís CD4 cell count at seroconversion (the earliest point at which antibodies against the HIV virus become detectable in a patientís blood). CD4 cell count shows how well a patientís immune system is working: the higher the CD4 count, the better.
- Each patientís viral load set point (an indicator of the point at which the immune system begins to attempt to fight the virus). Higher viral load set points increase the risk of developing AIDS and death in the absence of treatment.
The study found that CD4 cell count at seroconversion decreased over time and viral set point increased from 1980 until about 2002, when CD4 cell counts at seroconversion and viral set-point remained relatively stable thereafter. In particular, a typical individual infected in 2004 would reach a critically low CD4 cell count, and therefore require treatment, within 3.4 years, whereas an individual infected in 1980 would require treatment in 7 years. Similarly, someone infected in 2002 would typically have a higher viral load set-point than someone infected in 1980, giving them a 44% higher risk of transmitting HIV.
These findings provide strong indications that HIV-1 virulence and transmissibility have increased over the course of the epidemic. This has implications that are important for both HIV-infected people and public health in general.
The CASCADE findings are very different to those of another recently published study, which used data taken from HIV-infected people in Durban, South Africa and Gaborone, Botswana. This study suggested that HIV in southern African was mutating over time into a less virulent form. There are many possible reasons for these different results.
View the article summary on the Lancet HIV website
Read the study by Payne et al. mentioned in the news story
Read the article by Gus Cairns mentioned in the news story
Pantazis N, Porter K, Costagliola D, De Luca A, Ghosn J, Guiguet M, Johnson A, Kelleher A, Morrison C, Thiebaut R, Wittkop L, Touloumi G, for the CASCADE Collaboration in EuroCoord. Temporal trends in prognostic markers of HIV-1 virulence and transmissibility. An observational cohort study. Lancet HIV 2014. doi:10.1016/S2352-3018(14)00002-2 [full article] and [supplementary appendix]
Competing Risks Guide and public access dataset
A Competing Risks guide is now available to download here and the accompanying dataset to download here. This is a freely available guide and should be cited as: A Practical Guide on Modeling Competing Risk Data by Giorgos Bakoyannis and Giota Touloumi on behalf of CASCADE Collaboration www.cascade-collaboration.org downloaded on [insert date of download]. The research leading to these results have used a public version of the CASCADE dataset which has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under EuroCoord grant agreement nį 260694".
The 2nd International ACTIVATE HIV Course: 8th - 9th November, Glasgow 2008This exciting clinical training course is part of the ACTIVATE initiative and precedes the Ninth International Congress on Drug Therapy in HIV Infection. Clinicians from central and eastern
Competing Risks Guide
A Competing Risks guide is now available to download here and the dataset to download here. This is a freely available guide which should be cited as: A Practical Guide on Modeling Competing Risk Data by Giorgos Bakoyannis and Giota Touloumi on behalf of CASCADE Collaboration. www.cascade-collaboration.org. Downloaded on [insert date of download].
New EuroCOORD website
EuroCOORD now has a dedicated website www.eurocoord.net. The January 2008 newsletter is available here.
15th Conference on Retroviruses and Opportunistic Infections (CROI)
The following abstracts were accepted for the 15th CROI conference held in Boston 3rd Ė 6th February 2008:
- The effect of antiretroviral treatment of different durations in primary HIV infection (poster presentation).
- Changes over time in the risk of death following HIV
seroconversion compared with mortality in the general population (oral
12th International Workshop on HIV Observational Databases
The following abstracts have been accepted for the 12th International Workshop on HIV Observational Databases to be held in Malaga 27th - 30th March 2008:
- Relationship between immunodeficiency and specific non-AIDS causes of death: different approaches using the CASCADE Collaboration (oral presentation).
- Modelling pre- and post-HAART CD4: analysis on possible association between pre- and post-HAART slopes.
3 posters using CASCADE data were presented at the 2007 IAS Conference held in Sydney:
- Kholoud Porter presented "Continuing improvements in survival in the era of HAART" (abstract[http://www.ias2007.org/pag/Abstracts.aspx?AID=3715]).
- Kholoud Porter, on behalf of Giota Touloumi, presented "Determinants of immunological response to HAART resumption after treatment interruption in HIV-1 clinical practice" (abstract[http://www.ias2007.org/pag/Abstracts.aspx?AID=4717]).
- BenoÓt Marin presented "Association between CD4 and HIV RNA with non AIDS-related causes of death in the era of combination antiretroviral therapy (cART)" (abstract[http://www.ias2007.org/pag/Abstracts.aspx?AID=2335]).
The next CASCADE workshop will be held at the Radisson Hotel in Krakow, Poland on the 8-9th May 2008.
Welcome to CASCADEís new website!
We hope you find the new website useful and easier to navigate.
It has been primarily developed to provide a link between CASCADE partners and to keep them updated on project progress and output.
It will also include:
- publication summaries
- highlights of recent findings
- links to other relevant websites
If you have any comments or enquiries regarding the new website please email them to the webmaster.