Last week, the U.S. Centers for Disease Control and Prevention (CDC) announced a few changes to its annual vaccine guidelines for adults, including new recommendations on human papillomavirus (HPV), hepatitis B virus (HBV) and flu vaccines. The national health organization’s updated 2017 advisory report also includes a new vaccination recommendation for people living with HIV, The Chicago Tribune reports.

The CDC sets its adult immunization schedule every year based on recommendations from the Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts informed by the latest research in health science. Doctors use the annually updated vaccine schedule to ensure that patients are receiving the right vaccines for their age, medical condition and other risk factors. The 2017 list includes advice on 13 vaccinations. 

This year’s advisory switches up the HPV vaccine for adolescents, which helps prevent cervical cancer and a number of other tumors linked to HPV. Moving forward, young people who receive their first dose of the HPV vaccine before age 15 will require only one booster shot, which should be given at least five months after the first. Previously, the CDC recommended three shots for full protection.

In addition, a new vaccine schedule for hepatitis B adds people living with hepatitis C virus (HCV) to the list of those living with chronic liver disease who may benefit from an HBV vaccine series. The CDC also recommends that people with cirrhosis, fatty liver disease, alcoholic liver disease and  autoimmune hepatitis also get vaccinated against hepatitis B if they have not yet already. 

The updated 2017 advisory report also offers new vaccination advice for people who are HIV positive, recommending that all HIV-positive adults receive a two-dose series of MenACWY, a combination meningococcal vaccine that protects against deadly bacterial infections. 

This year’s recommendations have also removed the nasal flu vaccine from the CDC’s official roster, after numerous studies found it to be largely ineffective. People with egg allergies have also been cleared for any age-appropriate flu vaccine this year.

The 2017 advisory report ended by noting that U.S. vaccination rates among adults are still falling short of recommended levels—with only 20 percent of American adults age 19 and older having received a Tdap vaccine, which helps protect against tetanus, diphtheria and pertussis (whooping cough). 

The CDC also noted that access to health insurance helps dramatically increase the likelihood of vaccination and that insured adults are two to five times more likely to be vaccinated than their uninsured counterparts.