Vancouver, BC – The BC Centre for Excellence in HIV/AIDS (BC-CfE), in collaboration with Vancouver Coastal Health (VCH), has created a first-of-its-kind system for identifying HIV transmission outbreaks in near real-time, described in an article in The Lancet HIV published today. The innovative system has shown to be an effective and cost-saving means to address localized outbreaks of HIV transmission within the province of British Columbia.
“Understanding the movement of the virus is made possible by combining state-of-the-art molecular techniques with the wealth of population-based, anonymized data available through the BC-CfE’s continuously updated database,” said Dr. Julio Montaner, Director of the BC-CfE. “Our cutting-edge methods can be applied in any other setting to address localized outbreaks of HIV and—equally importantly—to address other high-burden contagious diseases such as hepatitis C.”
The BC-CfE’s Drug Treatment database currently holds over 32,000 HIV genotypes for nearly 9,000 residents of BC living with the disease. On average, five to six new HIV genotypes are deposited in the database every day. The monitoring system queries the database every hour, and reanalyzes the entire database when new records are found. The system preserves the same high level of data privacy, security and anonymization already established at the BC-CfE.
Localized outbreaks of HIV transmission are detected as "clusters" of genetically similar HIV infections affecting five or more individuals. Once a cluster is identified, it is linked to anonymized information on geographical regions and population groups most affected. Public health officials can direct targeted health support efforts based on these socio-demographic factors.
Through Treatment as Prevention (TasP®), the BC-CfE aims to reach key vulnerable populations with treatment immediately following a diagnosis. Early treatment improves quality of life and longevity for an individual living with HIV, while decreasing the likelihood they will spread the virus.
“Identifying clusters of HIV transmission helps public health to better target HIV prevention and community outreach services to the populations who can derive the most benefit,” said Dr. Réka Gustafson, Medical Health Officer with VCH and co-author of the paper. “This enables public health nurses to more effectively reach individuals living with HIV who are undiagnosed or not optimally treated, and support them to access testing, diagnosis and treatment services.”
In June 2014, the BC-CfE’s real-time monitoring system detected the rapid expansion (over three months) of a cluster with 11 new HIV cases. The cluster included eight individuals who had acquired transmitted HIV drug resistance, meaning the transmitted virus was already resistant to one of the three standard classes of antiretroviral drug therapy before the patients had ever been exposed to HIV treatment. This motivated an enhanced public health follow-up by VCH in the affected subpopulation within the specific jurisdiction, resulting in an increased number of individuals initiating HIV treatment. Over the subsequent year of follow-up, there was a pronounced reduction of transmitted drug resistance in relation to the cluster.
"This intervention represents the first time an automated evolutionary analysis of HIV sequences directly precipitated and supported a public health effort,” said Dr. Art Poon, BC-CfE Senior Research Scientist, the monitoring system developer and lead author of the paper. “It quite possibly changed the course of an outbreak in near real time.”
Phylogenetic clustering uses virus sequence diversity to investigate “hotspots” of rapid transmission. A phylogeny is a tree-based representation of how populations are related through common ancestors. For rapidly evolving viruses such as HIV, the phylogeny can provide an approximate depiction of the transmission history of the virus (although not necessarily exact due to the extensive genetic diversity of the virus within each host). When a cluster of HIV sequences from a number of infections have a high degree of genetic similarity, they are likely to be related by one or more recent transmission events. However, phylogenetic clustering cannot prove an episode of HIV transmission occurred between two given individuals.
Pioneered by the BC-CfE, TasP® consists of widespread HIV testing and the immediate offer of HIV treatment (highly active antiretroviral therapy, also known as HAART) to those who test positive. TasP® has been proven to greatly improve a patient’s quality of life, prevent progression to AIDS and extend longevity by decades, while reducing the likelihood of transmission by greater than 95 per cent. Within BC, the implementation of TasP®, with support from the provincial government, has resulted in significant declines in HIV transmission among injection drug users. In addition, TasP® has led to an 88 per cent decline in new AIDS cases and a 65 per cent drop in new HIV cases in BC since 1994. On World AIDS Day 2015 (December 1), the Canadian federal government formally embraced TasP® based on the pioneering work of the BC-CfE.
The BC-CfE is Canada’s largest HIV/AIDS research, treatment and education facility and is internationally recognized as an innovative world leader in combating HIV/AIDS and related diseases. BC-CfE is based at St. Paul’s Hospital, Providence Health Care, a teaching hospital of the University of British Columbia. The BC-CfE works in close collaboration with key provincial stakeholders, including government, health authorities, health care providers, academics from other institutions, and the community to decrease the health burden of HIV and AIDS. By developing, monitoring and disseminating comprehensive research and treatment programs for HIV and related illnesses, the BC-CfE helps improve the health of British Columbians.
VCH is responsible for the delivery of $3.4 billion in community, hospital and residential care to more than one million people in communities including Richmond, Vancouver, the North Shore, Sunshine Coast, Sea to Sky corridor, Powell River, Bella Bella and Bella Coola.
Caroline Dobuzinskis, BC-CfE
Phone: 604-682-2344 ext. 66536
Anna Marie D’Angelo, VCH