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San Diego's Hepatitis A Outbreak
By Acting More Quickly, the County and City of San Diego Might Have Reduced the Spread of the Disease

Report Number: 2018-116



In early March 2017, the County of San Diego Health and Human Services Agency (HHSA) announced a detected increase in hepatitis A cases. According to the U.S. Centers for Disease Control and Prevention (CDC), hepatitis A is a highly contagious liver disease that can range in severity from a mild illness lasting a few weeks to a severe illness lasting several months. In adults, hepatitis A presents with flu‑like symptoms, including fever, fatigue, and loss of appetite, and it can also cause jaundice, a condition that turns a person’s skin or whites of the eyes yellow. Once infected, most people fully recover and develop life‑long immunity. However, in rare cases, hepatitis A causes liver failure and death. On March 10, 2017, HHSA issued a health advisory to the San Diego medical community that an outbreak of hepatitis A was occurring and that it was disproportionately affecting two primary populations: individuals experiencing homelessness (the homeless population) and individuals who use illegal drugs (the illicit drug‑using population). HHSA stated in the health advisory that 19 cases of hepatitis A had occurred in the county of San Diego (county) from November 2016 through early March 2017, more than double the seven or eight cases that the county expected for that period.

Hepatitis A Prevention and Response

According to CDC, hepatitis A is a vaccine‑preventable disease that is transmitted through the ingestion of fecal matter. This transmission can occur in a number of ways, such as when infected individuals who did not wash their hands adequately after using the restroom touch objects or food that others subsequently touch or ingest. In the United States, the occurrence of hepatitis A has decreased by more than 90 percent over the last several decades, most likely because of the vaccination of at‑risk populations and the routine vaccination of children. However, periodic epidemics arise about once every decade, and hepatitis A remains one of the most frequently reported, vaccine‑preventable diseases in the United States, with many of the new cases stemming from Americans who travel to parts of the world where hepatitis A is common and then bring the disease home with them.

At-Risk Groups That CDC Recommends Should Receive the Hepatitis A Vaccine

CDC recommends vaccination for the following groups:

Source: CDC’s 2017 hepatitis A outbreak webpage.

CDC and the World Health Organization (WHO) offer guidance for dealing with hepatitis A that focuses on vaccination as the primary method of preventing the spread of the disease, especially among individuals with risk factors that include poor sanitation, lack of safe water, use of recreational drugs, living with an infected person, sexual partnering with someone with an acute hepatitis A infection, and travelling without immunization to areas where hepatitis A is prevalent. According to CDC, the hepatitis A vaccine is safe and effective. It consists of two doses, given six months apart, both of which are necessary for long‑term protection. However, a single dose of the vaccine within two weeks of contact with the virus may prevent a person from developing the disease and spreading it to others. CDC recommends vaccination against hepatitis A for the at‑risk groups listed in the text box; however, we noted that CDC did not include the homeless population as an at‑risk group.1 According to WHO, anyone who has not received the vaccine or previously contracted the hepatitis A virus is at risk of contracting the disease. This can include people who are not in an at‑risk population. In addition, both WHO and CDC note the importance of sanitation and hygiene efforts to stop the spread of the disease. Preventive measures include maintaining adequate supplies of safe drinking water; properly disposing of sewage; and encouraging effective personal hygiene practices, such as washing hands after using the restroom.

According to the Association of State and Territorial Health Officials (health officials association), time is of the essence when outbreaks occur. It has also stated that a timely and complete public health response can save lives, avert illness, and limit health care costs.

Government Agencies Involved in Protecting Public Health

National, state, and local public agencies contribute to protecting public health, including the control of infectious disease. As the nation’s health protection agency, CDC collaborates with a variety of outside organizations, like WHO, to provide the expertise, information, and tools that people and communities need to protect their health. At the state level, the California Department of Public Health (CDPH) uses these tools to guide its efforts to control and prevent infectious disease. The CDPH director acts as the State’s public health officer. According to CDPH, its fundamental responsibilities include infectious disease control and prevention, and its services include providing public health laboratory services and information about health threats.

State law requires CDPH to create a list of reportable diseases and conditions, and regulations require that health care providers report those diseases and conditions to the local health officer where the patients reside. State law requires that the governing body of each jurisdiction appoint a health officer. The State currently has 61 local health officers, one for each of the 58 counties and one each for three cities—Berkeley, Long Beach, and Pasadena. The local health officers must report the number of cases of certain diseases to CDPH at least weekly. The primary purpose of these reporting requirements is to alert other local health officers and the State’s public health officer to the presence of diseases within their jurisdictions.

At the local level, each jurisdiction is responsible for ensuring the public health of its residents. State law requires local health officers to take measures necessary to prevent the occurrence or spread of communicable diseases within the officer’s jurisdiction. Further, state law requires the governing body of each city to preserve and protect the public health, which includes the regulation of sanitary matters within the city, while the board of supervisors of each county must take necessary measures to preserve and protect the public health in the unincorporated territory of the county. Moreover, state law allows cities to contract with counties for the performance of all enforcement functions within the cities related to ordinances of public health and sanitation. In 1953 the city of San Diego (city) entered into such a contract with the county, which after several amendments, remains in effect as of the date of this report.


1 On October 24, 2018, the Advisory Committee on Immunization Practices, which is composed of medical and public health experts who develop recommendations to CDC on the use of vaccines, voted to add individuals experiencing homelessness to the at‑risk list. Go back to text

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