​

Fourteen years ago, Stanford Health Policy’s Douglas K. Owens and colleagues published a cost-effectiveness analysis that would change the face of HIV prevention. Their landmark study in The New England Journal of Medicine showed that expanding HIV screening would increase life expectancy and curb transmission of the disease — and was cost effective in virtually all health-care settings.

Not long after their model-based results were published, their findings became key evidence in the decision to expand screening by the Centers for Disease Control and Prevention. Their work has been used in HIV screening guidelines from the U.S. Preventive Services Task Force — which Owens now chairs — the American College of Physicians and the Department of Veterans Affairs, among others.

Owens and his Stanford colleague Margaret Brandeau, professor of management science and engineering, have led this team of decision scientists who have been at the forefront of developing scientific models for the screening and prevention of HIV for two decades now. This modeling team — which also includes colleagues from UCSF and Yale — has published nearly 250 peer-reviewed studies and is one of the most experienced and respected in the world.

But today, the opioid epidemic is threatening the hard-fought gains in the prevention and control of HIV and hepatitis C virus (HCV). In support of their continued work to address the opioid epidemic, Owens received a highly prestigious MERIT award from the National Institute on Drug Abuse (NIDA),which provides up to 10 years of funding for the team.

“We are extremely grateful to NIDA for this support and to our colleague at NIDA, Dr. Peter Hartsock, who has worked with us for over 20 years to mitigate the harms from HIV and HCV,” said Owens.

Image

The team will now turn its sights on the complex interplay of the opioid epidemic, and HIV and hepatitis C virus (HCV) transmission. The transmission of HCV has been fueled by the opioid epidemic, and HCV now kills more Americans than all other infectious diseases combined.  

“The unfolding opioid epidemic is a defining challenge for the public health and medical systems in the United States,” Owens, the principal investigator of the team, and his colleagues wrote in their grant proposal. “The reversal of life expectancy growth in the demographic groups most affected by the opioid epidemic represents the aggregation of a complex web of harmful public health and population trends, including a rise in overdoses, suicides, mental health afflictions, economic disadvantages, and infectious disease outbreaks.”

Indeed, for the first time since the 1960s, the U.S. life expectancy has contracted for the second year in a row; drug overdoses have been the leading cause of death for Americans under age 50, with an estimated two-thirds of those deaths resulting from opioids.

Since the last renewal of their NIDA-funding grant in 2013, the team has watched the dramatic rise of opioid overuse, injection drug use, and overdose become a national public health crisis, with more than 60,000 drug overdose deaths in the United States reported by the CDC.

“The growing use of needle-based opioids increases the likelihood of accelerating HIV and HCV transmission,” said co-investigator Jeremy Goldhaber-Fiebert, an associate professor of medicine and core faculty at Stanford Health Policy. “Identifying the best combination of approaches to reduce HIV and HCV transmissions stemming from the opioid epidemic is of critical public health importance.”

The other co-investigators on the team of the project, “Making Better Decisions: Policy Modeling for AIDS and Drug Abuse,” are:

1. Eran Bendavid, an infectious diseases physician and associate professor of medicine at Stanford who is another a seasoned HIV modeler and outcomes expert;
2. Keith Humphreys, professor of psychiatry and behavioral sciences at Stanford and a former senior policy advisor in the White House Office of National Drug Control Policy; 
3. David Paltiel, a Yale School of Public Health professor who pioneered policy options for mitigating the impact of HIV in the United States and abroad;
4. Gregg Gonsalves, an assistant professor of epidemiology at Yale and a 2018 MacArthur Foundation Fellow who will focus on developing new algorithms to detect and predict opioid-related outbreaks of HIV and HCV;
5. James Kahn of the Institute for Health Policy Studies at UCSF, professor of epidemiology and biostatistics and an expert on the individual and population impact of prevention and treatment for HIV, HCV and opioid use.

The End of AIDS? 

Toward 2012, a series of scientific advances led to calls for “the end of AIDS.” The two big factors were the cost of the “triple cocktail” of antiretrovirals plunging in developing countries and then huge donations from wealthy countries began pouring in to fight the disease.

Yet the researchers say successes have been too few and that the incidence of HIV remains far too high. About 40 million people were living with HIV around the world in 2017; an estimated 940,000 people died from AIDS-related illnesses that same year.

The year 2015 marked the first time in two decades that the number of HIV diagnoses tied to opioids increased.

"Although it was started by prescription opioid overprescribing, the epidemic has evolved to include significant injection opioid use which is now threatening to significantly increase the spread of infectious diseases like HIV and Hepatitis C,” said Humphreys.

The most visible example of an opioid-related HIV outbreak took place in Scott County, IN, in 2014-2015. A single infection introduced into the community resulted in nearly 200 new HIV cases within six months, largely related to oxymorphone injections. In 2017 and again in March 2018, two additional substantial outbreaks occurred in Scott County, likely linked to both risky sex and needle sharing. 

In addition, the CDC has identified 220 counties in 26 states that are uniquely vulnerable to HIV and HCV outbreaks related to opioid injections.

Image

“Developing models that forecast high-risk areas for HIV and HCV is essential for aligning surveillance and public health interventions with risk,” said Brandeau, a leader in designing models for the prevention of HIV and hepatitis, especially in drug abuse disorders.

There have also been striking increases in the injection of opioids and heroin that are closely linked to the spread of viral hepatitis. In the demographic areas most affected by opioids, the researchers found, diagnoses of acute hepatitis have more than quadrupled — reversing trends of the previous decade. And in the country as a whole, the number of new HCV cases has nearly tripled since 2010. 

“For any type of contact with an infected source such as a dirty needle, or even cocaine straws, HCV is by far the most rapidly transmissible of the blood-borne infections,” said Bendavid. “One of the challenging issues with hepatitis C is that its major health manifestations do not appear for many years after infection."

What’s the Plan? 

In the next five years, the team intends to evaluate how strategies to prevent and mitigate the harms of opioid use can decrease the spread of HIV and HCV and thereby reduce morbidity and mortality from opioid use. They have four specific goals: 

1. Model the effect of the opioid epidemic on transmission of HIV and HCV.
2. Model the epidemiological and population impacts of individual strategies to prevent and mitigate the harms of opioids and drug injection on HIV and HCV outcomes by evaluating prevention strategies;
3. Model the epidemiologic and population impact of portfoliosof strategies to mitigate the harms of opioid use and drug injection on HIV and HCV outcomes;
4. And model the impact of barriers to implementation of effective strategies to reduce the harms of opioid use on HIV and HCV.

“We will perform novel analyses assessing intervention impacts singly and in combination assessing outcomes for HIV, HCV and opioid use disorder,” the researchers wrote in their grant proposal.

Then, the researcher will model new methods for building complex multi-intervention and multi-disease models and developing adaptive testing algorithms for identifying outbreaks.

Finally, the team intends to assess the barriers and intervention approaches “that more realistically reflect implementation issues than current models and hence identify resource needs for system planning.”

Image