Emergency room visits for opioid overdoses rose 28.5% last year, compared with 2018 and 2019, a new study finds.

Opioid overdoses accounted for one in every 313 emergency room visits in 2020, compared with one in 400 in the previous two years, HealthDay reports.

“COVID-19, and the disruptions in every part of our social and work lives, made this situation even harder by increasing the risk of opioid misuse and relapse because people were separated from their social support and normal routines,” lead researcher Molly Jeffery of the Mayo Clinic said in a news release.

The researchers said the actual rate of opioid overdoses may be higher than the study suggests, because the number of people who overdose but don’t visit the emergency room is likely increasing.

Treatments for opioid use disorder, such as buprenorphine and methadone, must be more accessible, Jeffery said. The opioid overdose antidote naloxone also needs to be more widely available, she added.