The American Academy of Pediatrics (AAP) has issued new recommendations on how soon parents and doctors should protect newborns from potential exposure to hepatitis B virus (HBV), stating that healthy infants should now receive their first dose of the HBV vaccine within the first 24 hours of life, Medscape reports.

The group’s updated recommendations have been issued in large part because of a dramatic rise in opioid addiction that coincides with an increases in adult cases of hepatitis B across several states, according to the Centers for Disease Control and Prevention. Experts say the uptick in addiction raises the concern that women of childbearing age will contract the virus, increasing the risk of perinatal transmission.

In the United States, up to 1,000 new perinatal cases of hepatitis B occur every year, despite the AAP’s previous recommendations that infants receive the HBV vaccine upon discharge from the birth hospital. In some cases, this meant that some newborns did not get the shot until they were 2 or 3 days old.

Specifically, the recommendation states that medically stable babies born to mothers with a negative hep B test result should receive their first dose of the hepatitis B vaccine within 24 hours of birth as long as their birth weight is 2,000 grams (4.4 pounds) or more. If the mother is known to be positive for the hepatitis B surface antigen, the newborn should receive the shot within the first 12 hours of birth, regardless of birth weight. Doctors also recommend the vaccination be given within 12 hours of birth when the mother’s HBV status is unknown.

With this immunization schedule, experts say the hepatitis B vaccine should be 75 to 95 percent effective at preventing perinatal transmission of the liver virus. Following the updated protocols could help prevent thousands of American children from having a lifelong increased risk of HBV-related illnesses such as cirrhosis and hepatocellular carcinoma (the most common form of liver cancer).

The new recommendations also support the AAP’s goal to eventually eliminate all perinatally acquired hepatitis B infections in the United States — a vital component to the viral hepatitis elimination strategy in the United States.