Since March 2017, the
Hepatitis A virus (HAV) has spread across the United States. California has
experienced the most significant outbreak at 553 reported cases this year alone
(Center for Disease Control and Prevention CDC, 2017). Nationally and in San
Diego, homeless populations and intravenous drug users are the groups most
affected by HAV outbreaks (CDC, 2017).
HAV is an acute viral
infection that affects an estimated 1.4 million people worldwide every year
(World Health Organization WHO, 2015). According to the CDC, there were an
estimated 2,800 cases of HAV in the United States in 2015 (2017). Rates of HAV
have declined by 95% in the United States since the introduction of a vaccine
in 1995 (CDC, 2017). In San Diego County, cases of HAV infection
decreased from 645 in 1996 to 26 in 2016 (Health and Human Services Agency
HHSA, 2017). The virus is transmitted primarily by the fecal-oral route, via
ingestion of contaminated food or water sources, or by direct contact with an
infected individual (WHO, 2017). HAV infection in the United States occurs most
frequently in populations with specific risk factors related to travel,
hygiene, drug use, and sex practices (HHSA, 2017).
On September 1, 2017, the San
Diego Department of Public Health and Human Services Agency (SDHHSA) declared a
local public health emergency due to the high incidence and rapid spread of
HAV. The first reported case in this outbreak was a homeless man treated at La Mesa Hospital in November 2016. As
of November 15, 2017, 553 local cases were reported in San Diego. Of these, the
hospitalization rate was 67.6% and the death rate was 3.6%. This is the largest
person-to-person epidemic on record in the United States since introduction of
the HAV vaccine in 1995 (Weiss, 2017).
As of October 31, 2017, this
outbreak has affected people ages 5 to 96 years. Sixty-eight percent of those
affected are male, with 3% self-identifying as men who have sex with men.
Sixteen percent of the HAV cases are homeless individuals and 12% of the cases
are individuals who report injection or non-injection illicit drug use (CAHAN,
several clusters of epidemiologically associated cases, though no specific
food, beverage, or drug sources have been identified. Case clusters have been
reported in individuals who have used the same homeless services providers and
in locations with shared restrooms including jails, single room occupancy
hotels, residential drug treatment facilities, group homes, and assisted living
facilities. Six healthcare workers have contracted HAV in this outbreak, as
have seventeen food handlers (CAHAN 2017).
majority of the individuals in this outbreak having known indications for HAV
immunization, none of the patients had been fully vaccinated prior to becoming
ill. Full vaccination entails the completion of two injections six months
apart. Most people affected have been homeless residents of downtown San Diego
and El Cajon; however, cases have been confirmed in all parts of San Diego
county (NBC, 2017).
Applying the Social
Ecological Model to the Problem
The Social Ecological Model
(SEM) is a framework that can be applied to critically analyze health behavior
change in the Hepatitis A outbreak in San Diego (Joseph, 2016; McLeroy, 1988).
SEM integrates individual, social, and environmental factors affecting health
and delineates five levels of influence: individual, interpersonal,
institutional, community, and public policy (McLeroy, 1988). This approach is
useful to comprehensively assess public health issues and address the needs of
high risk groups most impacted by the outbreak, including homeless individuals
and illicit drug users (James et al., 2009).
Individual factors include
the characteristics of a person, such as their beliefs, behaviors, attitudes,
concepts, skills and knowledge (McLeroy, 1988). Homelessness impacts these
factors, as homeless individuals may not have regular access to facilities to
maintain adequate hygiene. Impeded access to hand washing promotes disease
contraction and transmission (CDPH, 2017). In addition to hand washing,
vaccination is an individual factor that has helped contain previous outbreaks.
Unfortunately, homeless populations may be more difficult to reach than the
general population in spreading education regarding the importance of
vaccination (CDPH, 2017).
The CDPH has been able to
examine the strains of HAV and trace the outbreak, concluding that the strains
of this outbreak are not more virulent than previous outbreaks (CDPH, 2017).
However, transmission and mortality during this outbreak is increased,
affecting more people than other documented outbreaks of the past 20 years, with
a mortality rate of nearly 4%. In previous outbreaks, mortality rates were
between 0.3-0.6% (Sisson, 2017). Reasons for this include a higher incidence of
comorbidities observed in the homeless population. As many as 5% of the
infected individuals have Hepatitis B, and up to 20% are believed to have
Hepatitis C. Both these diseases are known to increase mortality from HAV
(Sisson, 2017). Poor access to care is thought to be severely affecting this
population, as healthcare connected individuals are provided more information
about the disease and therefore are more likely to seek vaccination and earlier
treatment (CDPH, 2017).
affecting this outbreak include factors related to social networks and support
systems such as family, friends, and/or work (McLeroy, 1988). Transmission of
the virus is fecal-oral, and globally, the virus is most commonly spread by the
ingestion of contaminated food and water sources. However, transmission between
individuals through physical contact is possible. This outbreak is the largest
person-to-person outbreak not caused by contaminated food since 1996, when the
HAV vaccine was developed (SDHHSA, 2017).
affecting this outbreak include social institutions and their rules/regulations
of operation (McLeroy, 1988). In this case, the San Diego County Health and
Human Services Agency (HHSA) is the first line of defense in fighting a local
outbreak (SDHHSA, 2017). Typically, this office will be first to investigate an
outbreak and attempt to stop the spread of a disease. However, in this case,
fourteen deaths occurred before the outbreak was declared a local health
emergency. This may be because many of these individuals were homeless, and
this population is difficult to identify and trace (McDonald, 2017).
Community factors include how
public institutions relate and work together, and they are vitally important in
defining an event such as this (McLeroy, 1988). CPDH is coordinating local,
state and federal resources to fight this outbreak (CDPH, 2017). Critics have
stated the sluggish response to the outbreak has been a major contributor to
its severity, citing insufficient protocol for addressing person-to-person
outbreaks of HAV (O’Neill, 2017). Massive vaccination campaigns are underway to
increase personal and herd immunity, although these efforts are intended for
long-term results and the supply of adult doses of the vaccine has been
reported to be insufficient (CDPH, 2017).
Public policy may affect
change in situations such as this through implementation of local, state, and
federal laws (McLeroy, 1988). This outbreak was declared a public health
emergency on September 1, 2017 (SDHHSA, 2017). While vaccination against HAV
has been available since 1995 and has been recommended for all children since
1999, many adults have not previously received the vaccine (CDPH, 2017).
Rates of HAV have drastically
declined since the introduction of the vaccine in 1995. However, outbreaks
still occur in areas where sanitation is poor, people have limited access to
healthcare, and among intravenous drug users. Due to the fecal-oral pattern of
transmission of HAV, poor hygiene is a significant risk factor for contracting
the virus. As previously mentioned, the predominant groups affected by this
outbreak are homeless individuals and illicit drug users (Castles, 2017).
Personal risk factors include
having unprotected sex with an individual who has HAV, men who have sex with
men, and people with oral-anal sexual practices. Traveling to countries where
HAV is endemic also poses a risk of infection.
At a family level, risk
factors for infection include being in close contact with someone who has HAV
and providing care to someone with the disease. Those who work with children
are at risk due to inadequate hand hygiene common amongst children, and an
increased likelihood of fecal exposure.
San Diego has several major
risk factors at the community level. Despite its large population, the city has
inadequate public restrooms. This disproportionately affects homeless
individuals who may not have access to private toilets or soap and clean water for
hand washing (CDPH, 2017). Adults in San Diego may be under-vaccinated and may
not have adequate access to HAV diagnosis and treatment or post-exposure
prophylaxis (PEP) (Castles, 2017). HAV has an incubation period of 15-50 days,
and those with known exposure may avoid illness by seeking PEP (CDPH, 2017).
Contamination of the food or water supply is a common source of infection in
places where HAV is endemic, however, this has not been identified as a factor
in San Diego.
Protective Factors Against
The HAV vaccine is very
effective, even when the vaccine series is incomplete. One dose confers
immunity in 95% of individuals, while 100% become immune after two doses (CDPH,
2017). Children are now routinely vaccinated starting at 12 months of age (CDC,
2017). Living in one’s own home, having access to healthcare, washing hands
with soap and water, using condoms during sex, and avoiding oral-anal contact are
all individual protective factors that decrease the likelihood of contracting
For families, having a strong
family network, teaching children to wash their hands after using the restroom
and before preparing food, obtaining vaccinations for all family members, and
seeking treatment for family members who are intravenous drug users also
protect against HAV. At the community level, San Diego did not have protective
measures in place before the outbreak began despite having a large homeless
population, and the California Public Health Department did not have an
official protocol for person-to-person outbreaks of HAV (O’Neill, 2017). They
are now working to create such guidelines.
The SEM can also provide a
valuable framework for identifying prevention efforts. Health promotion is most
effective when interventions target all spheres of influence, including
individual, interpersonal, organization, community, and policy levels (Golden
& Earp, 2012). Although the CA Department of Health (CDH) details
interventions across levels, given the severity of the outbreak much work can
be done to improve existing interventions.
SDCHHSA recommends the
following individual-level interventions to prevent infection: vaccines for
at-risk groups, adequate hand washing with soap and water, avoiding sexual
interactions with infected individuals, and not sharing food, beverages,
cigarettes, or hygienic items such as towels, toothbrushes, and eating
utensils. Vaccination efforts targeting the at-risk population are well
underway and as of September 30, 2017, more than 54,000 adult HAV vaccines had
been administered across San Diego County. PEP protocols are also in place,
offering protection to those who believe they may have been exposed (CDPH,
2017). Business and homeowners are recommended to disinfect their home or
business using bleach and employees are obligated to notify their supervisor if
they are diagnosed with the virus (CDPH, 2017).
Although these interventions
are essential in preventing further spread of disease, few supports are specific
to the homeless population where the outbreak is most prevalent. With limited
access to resources, homeless individuals can further enhance prevention
efforts by utilizing public hand washing stations. In an effort to address the
homeless population directly, San Diego has also paired public health nurses
with homeless outreach workers to visit homeless encampments and offer
education, vaccines, and information about available resources (CDPH, 2017).
Interventions at the
interpersonal level are needed to increase public knowledge and ensure an
understanding of recommendations (Golden & Earp, 2012). SDCHHSA has
provided online resources in multiple languages including a website targeting
the needs of the homeless population by listing public restrooms, hand washing
stations, and immunization sites. However, greater effort at the interpersonal
level is needed to disseminate these resources, particularly since homeless
individuals often have limited internet access. Handing out flyers with this
information may be more effective.
At the organizational level,
prevention and education campaigns are maintained by SDPHHS, whose website is a
hub of information and resources for healthcare providers and individuals. As
part of the SDPHHS Prevention Outreach Campaign, ads have been placed in
trolley and bus stations throughout the city, over 50 presentations have been
made to community partners, and educational materials on vaccinations and hand
hygiene have been widely distributed to partnering organizations. Efforts to
improve public sanitation have also gone into effect, with the addition of
publicly accessible toilets and hygiene stations with soap and water. Sidewalk
scrubbing initiatives are underway in an effort to remove contagious human
waste from public spaces, particularly in areas where people sleep on
To further their efforts, San
Diego might consider allocating more funding to homeless shelters and
housing-first initiatives that seek housing for those who need it, regardless
of substance use or employment status. Because intravenous drug users are also
at increased risk, supporting needle exchange programs and safe injection
sites, and increasing access to methadone and buprenorphine programs may also
Current prevention efforts at
the policy level include childhood Hepatitis A and B vaccination based on
guidelines provided by the CDC, and chlorination of public water, which
prevents the spread of HAV and many other water-borne contaminants. Since the
HAV outbreak began, CDPH has helped to coordinate efforts between counties to
avoid further spread of the disease. These efforts have included enhanced
communication with the CDC, increased surveillance to identify potential cases
of HAV early, and increased access to vaccines, availability of lab testing to
expedite treatment, and dissemination of information to the surrounding
community (CDPH, 2017).
To further their preventative
work, vaccination for other communicable diseases, increased access to public
restrooms and hand washing stations, and housing-first initiatives should be
the next steps in preventing future preventable health crises. Additional
efforts that might be considered include increasing access to long-term mental
health facilities and addiction rehabilitation programming, and creating
screening guidelines to identify people who are at risk of becoming homeless or
substance dependent. Increasing the accessibility of primary care may also aid
in prevention. This could be achieved by
allocating increased funding to community health centers that serve at-risk
populations. Alternatively, improving access to healthcare by implementing
universal Medicaid may also prove effective.