End Hep C SF, a consortium of public health workers, medical providers, advocates and people living with hepatitis C, has released the first-ever estimate of the number of people thought to be living with active hepatitis C virus (HCV) infection in San Francisco.
The new estimate suggests that nearly 13,000 city residents are currently living with hepatitis C. People who inject drugs, baby boomers and men who have sex with men are disproportionately affected, according to a summary of the report. Complete findings will appear in a forthcoming medical journal article.
San Francisco is one of the only cities in the US to have a robust estimate of how many people are living with hepatitis C, said Emalie Huriaux of Project Inform, who sits on the End Hep C SF steering committee.
“Having this information is critical, as it both illustrates the great impact hepatitis C has on the city – with nearly two out of every 100 residents living with the virus – and it gives us a baseline by which we can measure our success toward the goal of eliminating the public health threat of hepatitis C in San Francisco,” Huriaux said.
Hepatitis C often has no symptoms at early stages and many people are not aware they carry the virus. But over years or decades, chronic HCV infection can lead to serious liver disease including cirrhosis and liver cancer. There are now effective and well-tolerated treatments that can cure most people in two to three months, but due to their high cost they are not available to everyone who needs them.
To learn more about the hepatitis C epidemic in San Francisco, End Hep C SF compiled and analysed public health data from multiple sources.
The study found that approximately 23,000 people – or 2.7% of the 2015 San Francisco population of about 860,000 – have antibodies against HCV, indicating past exposure to the virus. This is significantly higher than the national antibody prevalence of about 1.7%, according to the report.
About one in five people will clear HCV naturally, and others do so with treatment, leaving an estimated 13,000 people – or about 1.5% of the population – with active infection. People with active HCV infection are susceptible to progressive liver damage and can transmit the virus to others.
Nationwide, the Centers for Disease Control and Prevention (CDC) estimates that approximately 3.5 million people are currently living with HCV, out of a total population of around 325,000 million.
The new San Francisco data reveal substantial differences in hepatitis C rates across population subgroups.
In San Francisco, as is the case nationwide and globally, people who inject drugs have the highest likelihood of having hepatitis C, as the virus is readily transmitted via syringes and other drug injection equipment. While people who inject drugs make up only 3% of the city’s total population, they account for 70% of people with active HCV infection.
Baby boomers – people born between 1945 and 1965 – traditionally have the highest rate of hepatitis C in the US, and the CDC recommends that everyone in this age group should be screened for HCV at least once. In San Francisco, this age group makes up 21% of the population, but accounts for 38% of active HCV infections.
Gay and bisexual men, who make up around 8% of the city's population, account for 13% of active HCV infections, according to the report. Sexually transmitted acute HCV infection is mostly seen among HIV-positive men who have sex with men. HCV transmission has been linked to a variety of sexual activities including condomless anal sex and fisting; it is not yet clear whether the virus is transmitted through semen as well as blood.
Transgender women in San Francisco appear to have a particularly high rate of hepatitis C. Although this group makes up just 0.1% of the city's population, the report estimates that one in six may be living with HCV.
The estimated 13,000 people with active HCV infection is roughly similar to the approximately 16,000 people thought to be living with HIV in San Francisco. But the distribution is quite different. Gay and bisexual men account for nearly 90% of people with HIV, while people who inject drugs account for about 20% (some people fall into both categories). Nearly three-quarters of gay men with HCV also have HIV, according to the report.
The consortium estimates that more than 4500 people have been treated for hepatitis C based on reports from local health care facilities. The report says that "a few thousand" people have been cured, but this number is not easy to determine. While the newest direct-acting antiviral therapies have cure rates exceeding 95%, older therapies were less effective and many people stopped treatment early due to side-effects.
"Given recent medical advances, we now have the potential not just to reduce but to eliminate hepatitis C as a public health threat in San Francisco," concluded End Hep C steering committee member Dr Annie Luetkemeyer of the University of California at San Francisco.
End Hep C SF Hepatitis C in San Francisco. 2017.