Move over, baby boomers. California’s Department of Public Health is now reporting that hepatitis C virus (HCV) infections are now skyrocketing among millennials across the state—with new infections increasing 55 percent among men ages 20 to 29 and 37 percent among women in the same age group in the Golden State over the last decade, Capitol Weekly reports.

The change in at-risk demographics could call for a major shift in California’s HCV screening policies and outreach strategies. Until recently, state health officials considered baby boomers (those born between 1945 and 1965) to be at greatest risk for infection, since hepatitis C wasn’t screened for in the blood supply until 1992. However, a recent surge in opioid addiction and injection drug use among young people across the state and the country appears to have changed that.

According to newly released data from California’s Department of Health, in 2015, nearly 4,000 people were hospitalized for an opioid overdose across the state, and more than 2,000 people died as a result of their overdose. As in many other states, California’s HCV and addiction epidemics appear to be growing most quickly among young white men in rural or suburban areas. In 2015, 18 counties had an opioid overdose mortality rate at least 50 percent higher than the statewide average. Statewide the rate is 4.73 deaths per 100,000; Tuolumne and Humboldt had among the highest rates in the state by far: 24.69 and 13.76, respectively.

State health officials say the facilities that treat hepatitis C are perpetually underfunded and that testing and prevention efforts that target young people are lacking. Of California’s 58 counties, only 23 have syringe service programs (which distribute clean needles to injection drug users and often refer them to HCV testing). A recent Oxford University study among hepatitis C–infected young people also found that 80 percent lived more than 10 miles from the closest needle exchange.

Hepatitis C advocates in California are also worried about future GOP efforts to gut the Affordable Care Act (ACA), arguing that doing so would have a major impact on millennials affected by hepatitis C. Currently, California’s Medicaid program, Medi-Cal, covers HCV treatment and testing, with several grant-funded projects focused on serving underserved and at-risk populations. Without an insurance safety net, young people may no longer be able to access the care or prevention they need to help quell the outbreak.