Hepatitis Viruses

Hepatitis, or liver inflammation, is most commonly caused by infection with a hepatitis virus. Chronic viral hepatitis is the major cause of liver cirrhosis and liver carcinoma. In the U.S., the most common hepatitis viral infections in the U.S. are hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV).¹ While HAV is transmitted through the fecal-oral route, HBV and HCV are transmitted though infected blood; other bodily fluids can also transmit HBV.^{1, 2}

HAV is acquired in the U.S. primarily through close personal contact with an infected person or exposure to contaminated food or water.^{1, 3} Unlike HBV and HCV, HAV does not cause chronic infection; cases of HAV infection are generally self-resolving within 4-7 weeks with mild to moderate symptoms (e.g., fever, fatigue, malaise, loss of appetite), but symptomatic relapse may occur in up to 20 percent of cases, particularly among individuals of older age groups.^{1, 4, 5}

In 2019, a total of 18,846 acute cases of HAV were reported to CDC from 50 states and the District of Columbia, with an estimated 37,700 acute HAV infections occurring that same year.⁶ In recent years, the Centers of Disease Control and Prevention (CDC) has been monitoring an emerging outbreak of HAV infection in the United States, with 36 states reporting just over 42,000 cases since 2016.

Since 1995, vaccines to prevent HAV infection have been available in the U.S.¹ In 1996, CDC’s Advisory Committee on Immunization Practices (ACIP) recommended administration of HAV vaccine to persons at increased risk for the disease, including international travelers, men who have sex with men (MSM), persons who use drugs and persons who inject drugs (PWID), and children living in communities with high rates of disease. In 2006, ACIP expanded these recommendations to include routine vaccination of children aged older than one year in all 50 states.¹

Epidemiology and Risk to Dental Personnel

HBV infection is an occupational risk to individuals who have exposure to blood, blood products or other bodily fluids. HBV is transmitted via blood or sexual contact, and the virus is transmissible through percutaneous or mucosal exposure to infectious blood or body fluids.⁷ HBV can remain infectious on environmental surfaces for at least seven days and can also be transmitted in the absence of visible blood.⁷

Symptoms of the acute illness caused by HBV infection include nausea, malaise, abdominal pain, and jaundice; untreated, it can then develop into a chronic condition, predisposing individuals to cirrhosis (scarring) of the liver, liver cancer, liver failure, and death.⁸ After the development of effective HBV vaccines, the incidence of acute HBV infection declined and has stabilized.^{1, 6} In 2019, 13,859 new cases of chronic hepatitis B were reported in the U.S.⁶ Chronic HBV infection remains a public health challenge both in the U.S. and abroad: between 847,000 to 2.2 million people in the U.S. are estimated to have chronic HBV infection,⁸ with Asian-American adults (foreign- or U.S.-born) having the highest estimated risk of chronic HBV infection.⁹ Overall, less than five percent of HBV-infected older children and adults develop chronic infection,¹⁰ which is estimated to cause over 1,800 deaths in the U.S. each year (primarily from liver failure).¹¹

HBV is a bloodborne pathogen and can be transmitted through infected blood from a percutaneous injury (such as a needlestick or cut with a sharp object) or through contact with mucous membranes, non-intact skin with HBV-positive blood, or other bodily fluids.⁸ Although blood is the most efficient vehicle of infection, infectious HBV has been found in other body fluids, including bile, nasopharyngeal secretions, saliva, and sweat.¹² Even though most body fluids have low concentrations of infectious HBV particles, contact should be avoided with all other potentially infectious body fluids (e.g., saliva in dental procedures).

Risk of HBV infection after a needlestick with HBV-positive blood ranges from 23% to 62% (depending on the HBV e antigen status of the source person).¹² Percutaneous injuries are the most efficient mode of HBV transmission, but the majority of HBV infections among dental practitioners occur from infected blood or body fluids coming in contact with mucosa or existing breaks in the surface of the skin.¹²

Hepatitis B Vaccine

The CDC’s ACIP recommends that the following groups receive HBV vaccination⁸:

• All infants
• Unvaccinated children younger than 19 years of age
• Adults aged 19 to 59 years of age
• Adults aged 60 years and older with risk factors for HBV infection

Adults older than 60 years without known risk factors for HBV infection may consider HBV vaccination.⁸ For adults, the vaccine is given in two or three injections, depending on the vaccine type used.¹³ If there is an interruption between HBV vaccine doses, the series does not need to be restarted, but the next dose should be administered as soon as possible.⁸

Dental health care personnel are at risk for occupational exposure to bloodborne pathogens, including HBV.^{14, 15} The Occupational Safety and Health Administration requires that employers shall make available the hepatitis B vaccine and vaccination series to all employees who have occupational exposure. Historically, dental professionals had a three- to four-fold higher risk of HBV infection than the general population, but vaccines and precautionary methods have contributed to decrease that risk.¹⁶ Those who are unsure whether they have been fully vaccinated can test their immunity to HBV through serologic assays.⁸ No booster is currently recommended for persons with normal immune status who have been fully vaccinated.⁸ Although studies to assess whether booster doses of HBV vaccine will be necessary to maintain lifelong protection are ongoing,¹⁷ recent data from a 30-year cohort follow-up suggests that booster doses may not be needed.¹⁸

Epidemiology and Risk to Dental Personnel

HCV infection is the most common bloodborne infection in the United States,¹⁹ and chronic HCV infection is the leading cause of liver transplants.²⁰ Infection with HCV may begin with a short-term illness, although the majority of people with acute HCV infection do not have any symptoms.²¹ Symptoms of an acute infection include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, joint pain, and jaundice.²¹ This acute phase is followed by chronic HCV infection for the approximately 75-85% of newly infected persons who do not clear the initial infection.¹ Chronic HCV rarely has symptoms, but can result in long-term health problems, including liver dysfunction, cancer, and death.^{21, 22} In 2019, 14,242 hepatitis C-associated deaths were reported among U.S. residents.⁶ Estimated cases of acute HCV infection in the United States have more than doubled from 2012 through 2019 (from 24,700 to 57,500 estimated cases).⁶

HCV is transmitted primarily through parenteral exposures to infectious blood or body fluids that contain blood. Possible risk factors include:²¹

• Current or former injection drug users, including those who injected only once many years ago
• Recipients of clotting factor concentrates made before 1987, when less-advanced methods for manufacturing those products were used
• Recipients of blood transfusions or solid organ transplants prior to July 1992, before better testing of blood donors became available
• Chronic hemodialysis patients
• People with known exposures to HCV, such as:
  • health care workers after needlesticks involving HCV-positive blood
  • recipients of blood or organs from a donor who tested HCV-positive
• People with HIV infection
• Children born to HCV-positive mothers

The authors of one recent study concluded that there is strongly suggestive evidence that the national increase in acute HCV infections is related to the country’s ongoing opioid epidemic and associated increases in injection drug use.²³

HCV can be transmitted through a percutaneous injury (such as a needlestick or cut with a sharp object) or contact between mucous membranes or non-intact skin with blood, tissue, or other bodily fluids.²¹ After a needlestick exposure to HCV-positive blood, the risk of HCV infection is approximately 1.8%.²¹ HCV has been detected in saliva, but no undisputed case of HCV salivary transmission has been documented.²⁴ One recent Canadian study indicated a risk of potential HCV transmission between two cases linked to the same dental facility in the province of Ontario (improper instrument reprocessing and/or unsafe medication practices were cited as possible causes).²⁵ Cases of acute viral hepatitis in individuals without traditional risk factors for hepatitis C might be due to health care-related transmission of HCV.

Hepatitis C Treatment

Unlike HBV infection, there is no effective vaccine or post-exposure prophylaxis available for HCV infection. Prior infection with hepatitis C does not protect against later infection.²¹ Older treatments, including interferon injections and ribavirin, had to be given for up to 48 weeks of therapy, were associated with significant adverse effects in many patients, and had only modest effect on sustained viral response (SVR; associated with improvement in all-cause and liver-related mortality from HCV).²² Current “interferon sparing” treatment regimens employing combinations of orally administered direct-acting antiviral agents (e.g., sofosbuvir, ledipasvir) are capable of curing HCV infection in up to 90% or more of cases, including patients who are treatment naïve, or those with cirrhosis or who are treatment experienced.^{22, 26, 27} Current drug regimens also have considerably shortened treatment durations (e.g., 12 weeks).^{22, 27}

Dental personnel decrease the risk of HBV or HCV infection by following standard precautions, which include wearing barrier precautions (e.g., gloves, masks, and protective eyewear) whenever there is potential for contact with body fluids or mucous membranes, using work practice and engineering controls for sharps safety, and following safe injection practices.¹³ The CDC’s recommendations on infection control include the sterilization and disinfection of dental equipment and instruments.¹³ Disinfecting the dental care environment after any contact with potentially infected body fluids is also important since HCV can survive at room temperature on surfaces for more than five days, and HBV can survive for at least one week.¹⁸ The CDC recommends cleaning exposed surfaces with a 1:10 dilution of bleach to water.¹² Correctly following conventional sterilization techniques has been demonstrated to eliminate HBV DNA and HCV RNA from dental instruments.¹⁶ Adherence to all infection control recommendations is vital to preventing the spread of hepatitis.

Employees should immediately report exposure incidents to the employer to permit timely medical follow-up. In the event of an exposure incident (e.g., needlestick, sharps injury), employers are required to refer the exposed employee to a licensed health care professional who can provide post-exposure evaluation and follow-up services that include: documentation of the exposure; identification of the source individual; testing of the source individual’s blood for infectivity status; collection of the blood and testing; post-exposure prophylaxis, if indicated; counseling; and a written opinion documenting that the employee was provided services. The ADA and OSHA have developed an informational resource on “Employer Obligations After Exposure Incidents” for dental professionals.²⁸

Obtaining and reviewing the patient’s medical history can assist in the identification of those potentially infected with viral hepatitis.²⁹ Care of patients with acute viral hepatitis should generally be limited to urgent care.^{24, 29} Consultation with the patient’s physician can help to establish a safe treatment plan adapted to the medical condition of the patient.²⁹

Examples of oral manifestations of liver dysfunction include: mucosal membrane jaundice, bleeding disorders, petechiae, increased vulnerability to bruising, gingivitis, gingival bleeding, fetor hepaticus (i.e., a distinctive breath odor associated with hepatic encephalopathy), cheilitis, smooth and atrophic tongue, xerostomia, bruxism, or crusted perioral rash.¹⁶ Infection with HCV may also increase the likelihood of Sjögren disease, sialadenitis, and oral lichen planus.¹⁶

The degree of a patient’s liver functional impairment can be determined via consultation with the medical physician, since liver disease has important implications for dental treatment.²⁹ Patients with liver disease may have decreased plasma coagulation factor concentrations; before any invasive procedure is performed in these patients, coagulation and hemostasis tests can be informative.^{16, 29} Liver disease may also result in alterations in the metabolism of certain drugs.¹⁶ The patient’s physician can be consulted to discuss which drugs are used, and their possible interactions.

Dental health care personnel must implement proper infection control measures when treating hepatitis-positive patients, as for any patient, but should also create a welcoming and nonjudgmental environment for all patients.³⁰ In addition, the CDC recommends that if dental health care personnel are acutely infected with HAV, they be removed from patient-care environments until seven days after onset of jaundice.³¹

1. Centers for Disease Control and Prevention. Surveillance for Viral Hepatitis--United States, 2016. U.S. Department of Health and Human Services 2018. https://archive.cdc.gov/www_cdc_gov/hepatitis/statistics/2016surveillance/commentary.htm. Accessed September 22, 2021.
2. Nelson NP, Weng MK, Hofmeister MG, et al. Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020. MMWR Recomm Rep 2020;69(5):1-38.
3. Ramachandran S, Xia GL, Dimitrova Z, et al. Changing Molecular Epidemiology of Hepatitis A Virus Infection, United States, 1996-2019. Emerg Infect Dis 2021;27(6):1742-45.
4. Lemon SM, Ott JJ, Van Damme P, Shouval D. Type A viral hepatitis: A summary and update on the molecular virology, epidemiology, pathogenesis and prevention. J Hepatol 2017.
5. Zhou Y, Callendret B, Xu D, et al. Dominance of the CD4(+) T helper cell response during acute resolving hepatitis A virus infection. The Journal of experimental medicine 2012;209(8):1481-92.
6. Centers for Disease Control and Prevention. 2019 Viral Hepatitis Surveillance Report.  Published July 2021.
7. Schillie S, Vellozzi C, Reingold A, et al. Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2018;67(1):1-31.
8. Centers for Disease Control and Prevention. Clinical Overview of Hepatitis B. 2024 https://www.cdc.gov/hepatitis-b/hcp/clinical-overview/. Accessed June 10, 2024.
9. Le MH, Yeo YH, Cheung R, et al. Chronic Hepatitis B Prevalence Among Foreign-Born and U.S.-Born Adults in the United States, 1999-2016. Hepatology 2020;71(2):431-43.
10. Weinbaum CM, Williams I, Mast EE, et al. Recommendations for identification and public health management of persons with chronic hepatitis B virus infection. MMWR Recomm Rep 2008;57(Rr-8):1-20.
11. Bixler D, Zhong Y, Ly KN, et al. Mortality Among Patients With Chronic Hepatitis B Infection: The Chronic Hepatitis Cohort Study (CHeCS). Clin Infect Dis 2019;68(6):956-63.
12. Centers for Disease Control and Prevention. Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to HBV, HCV, and HIV and Recommendations for Postexposure Prophylaxis.  2001;50(RR11):1-42.
13. Centers for Disease Control and Prevention. Recommended Adult Immunization Schedule for ages 19 years or older, United States, 2019. U.S. Department of Health and Human Services. https://www.cdc.gov/vaccines/hcp/imz-schedules/adult-age.html. Accessed March 6, 2019.
14. Centers for Disease Control and Prevention. Summary of Infection Prevention Practices in Dental Settings: Basic Expectations for Safe Care. U.S. Department of Health and Human Services 2016. https://www.cdc.gov/oralhealth/infectioncontrol/pdf/safe-care2.pdf. Accessed March 7, 2019.
15. Cleveland JL, Gray SK, Harte JA, et al. Transmission of blood-borne pathogens in US dental health care settings: 2016 update. J Am Dent Assoc 2016;147(9):729-38.
16. Cruz-Pamplona M, Margaix-Muñoz M, Gracia Sarrión-Pérez MG. Dental considerations in patients with liver disease. J Clin Exp Dent 2011;3(2):e127-34.
17. Immunization Action Coalition. Ask the Experts: Diseases and Vaccines: Hepatitis B.  2018. http://www.immunize.org/askexperts/experts_hepb.asp. Accessed March 7, 2019.
18. Bruce MG, Bruden D, Hurlburt D, et al. Antibody Levels and Protection After Hepatitis B Vaccine: Results of a 30-Year Follow-up Study and Response to a Booster Dose. J Infect Dis 2016;214(1):16-22.
19. Hofmeister MG, Rosenthal EM, Barker LK, et al. Estimating Prevalence of Hepatitis C Virus Infection in the United States, 2013-2016. Hepatology 2019;69(3):1020-31.
20. Bhamidimarri KR, Satapathy SK, Martin P. Hepatitis C Virus and Liver Transplantation. Gastroenterology & hepatology 2017;13(4):214-20.
21. Centers for Disease Control and Prevention. Clinical Overview of Hepatitis C https://www.cdc.gov/hepatitis-c/hcp/clinical-overview/. Accessed June 10, 2024.
22. Webster DP, Klenerman P, Dusheiko GM. Hepatitis C. Lancet 2015;385(9973):1124-35.
23. Zibbell JE, Asher AK, Patel RC, et al. Increases in Acute Hepatitis C Virus Infection Related to a Growing Opioid Epidemic and Associated Injection Drug Use, United States, 2004 to 2014. American Journal of Public Health 2017;108(2):175-81.
24. Dahiya P, Kamal R, Sharma V, Kaur S. "Hepatitis" - Prevention and management in dental practice. J Educ Health Promot 2015;4:33.
25. Johnston C, Sunil V, Ser D, et al. A public health response to a newly diagnosed case of hepatitis C associated with lapse in Infection Prevention and Control practices in a dental setting in Ontario, Canada. Canada communicable disease report = Releve des maladies transmissibles au Canada 2021;47(7-8):347-52.
26. U.S. Food and Drug Administration. FDA approves Epclusa for treatment of chronic Hepatitis C virus infection.  2016. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm508915.htm Accessed March 6, 2019.
    
27. Lowes R. FDA Approves Once-Daily Viekira XR for Hepatitis C. Medscape Medical News:  2016. http://www.medscape.com/viewarticle/866680. Accessed March 6, 2019.
    
28. American Dental Association and Occupational Safety and Health Administration. Employer Obligations After Exposure Incidents.  2012. https://www.ada.org/resources/research/science-and-research-institute/employer-obligations-after-exposure-incidents-osha. Accessed March 7, 2019.
29. Yepes JF. Hepatic disease. In: Patton LL, Glick M, editors. The ADA Practical Guide to Patients with Medical Conditions. 2nd ed. Hoboken, NJ: John Wiley & Sons, Inc.; 2016. p. 121-33.
    
30. Setia S, Gambhir RS, Kapoor V. Hepatitis B and C infection: Clinical implications in dental practice. Eur J Gen Dent 2013;2:13-9.
31. Centers for Disease Control and Prevention. Guidelines for Infection Control in Dental Health-Care Settings — 2003 (December 19, 2003 / Vol. 52 / No. RR-17). U.S. Department of Health and Human Services 2003. http://www.cdc.gov/mmwr/PDF/rr/rr5217.pdf. Accessed March 7, 2019.

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• Centers for Disease Control and Prevention: Best Practices in Dental Infection Prevention and Control
• Centers for Disease Control and Prevention: Clinical Overview of Hepatitis B
• Centers for Disease Control and Prevention: Clinical Overview of Hepatitis C
• Centers for Disease Control and Prevention: Hepatitis B Vaccination
• Centers for Disease Control and Prevention: Preventing Unsafe Injection Practices
• Centers for Disease Control and Prevention: ABCs of Hepatitis
• Centers for Disease Control and Prevention: What is Viral Hepatitis?