By Dr. Jennifer Sedillo
Faculty Member, Public Health, American Public University
Washington’s State’s recent measles outbreak appears to be under control. As of Feb. 17, the potentially last measles cases have been identified out of the 61 confirmed cases in Clark County. Currently, there are no suspected cases being investigated elsewhere.
Of these cases, 54 patients were not immunized and only two were confirmed to have had one measles-mumps-rubella (MMR) vaccination (two are required for full immunization). Other cases were identified due to a measles outbreak among four patients in Multnomah County, in neighboring Oregon.
Clark County Worked Swiftly and Effectively to Control the Measles Outbreak
Measles is a highly communicable disease that can easily be transmitted from one person to another. Because the measles virus can survive up to two hours in the air, it can be also be transmitted without actual face-to-face contact.
Consequently, Clark County Public Health officials needed to act quickly to prevent many more infections. Through clear communication, good resource allocation and the use of public health interventions, Clark County Public Health contained the measles outbreak quickly and effectively. The homepage of the Clark County Health Department provided information on measles and daily updates on reported cases. As a result, the public was informed and could avoid potential exposure sites.
On Jan. 25, the Governor of Washington, Jay Inslee, declared a state of emergency seven days after Clark County declared a local public health emergency, explaining that the “outbreak of measles…creates a substantial likelihood of risk to the citizens of Clark County and the seven cities therein.”
The governor’s declaration offered resources for outbreak response and community recovery. Inslee stated: “The Washington State Department of Health has instituted an infectious disease Incident Management Structure to manage the public health aspects of the incident” and that the “plans and procedures of the Washington State Comprehensive Emergency Management Plan [will] be implemented.”
In Clark County, suspected and confirmed measles patients were required to remain at home to stop transmission of the disease. Furthermore, the public health department required students and staff without documented immunity to measles to stay out of all schools, child care facilities and other places where groups congregate.
People who have been properly vaccinated against measles are not at risk for infection or for transmitting the disease. Only two cases in the Washington measles outbreak were found to have been vaccinated, but only one vaccine out of the two-dose series. This mandate was a necessary intervention to help control disease transmission. It ultimately led to the break in the chain of infection that stopped the transmission of the disease.
Lack of Vaccinations in School-Age Children Contributed To Measles Outbreak
Measles was declared eliminated in the U.S. in 2000 and in North and South America in 2002. This is in large part due to the implementation of the measles vaccination program in 1963, which is widely seen as a public health triumph. Patients who receive the two-dose MMR series are protected from measles with 97% of patients having full immunity.
According to the World Health Organization (WHO), a population needs to achieve a vaccination rate of 93-95% to stop transmission of a disease like measles. The goal is to give vaccinations to 95% of the population.
When vaccination rates are below this level, measles can be transmitted if it is introduced into the population. Clark County, for example, reported that last year only 78% of children in the six- to 18- age range and 81% of children ages one through five had the age-appropriate doses of the vaccine. This is well below the target level of 95% and allowed the measles virus to more easily spread in the community.
WHO further recommends for all countries to eliminate measles; it is critical that school-age children (ages five though nine) have documented immunity. In Clark County, more than 72% of the measles cases (44 out of 61 confirmed cases) occurred in children one to 10 years old. This high rate of infection is due to the high exposure of the virus in school settings, whereas children under five who do not yet attend school may be less likely to be exposed in public settings.
Why Has There Been a Reduction in Vaccination Rates?
Many people do not view measles as a threat any longer. Unfortunately, the measles virus is still causing infections worldwide, so it can come to the U.S. through patients who have traveled abroad and contracted the virus outside the U.S.
In this latest outbreak, Clark County Public Health identified its measles outbreak as coming from a virus that originally circulated in Eastern Europe.
The Centers for Disease Control and Prevention (CDC) has a campaign to target parents who are not familiar with measles with the message, “It isn’t just a little rash.” Measles can result in severe infections with one out of every four patients hospitalized. In other, rarer cases -- one out of 1,000 -- a measles infection results in encephalitis, brain damage or even death.
Many parents believe young children receive too many immunizations. That belief is untrue; a healthy, competent immune system can handle many daily exposures that result from normal environmental interaction. Furthermore, another cause of the decline in vaccination rates is the widespread myth that vaccines are linked to autism.
When Is Mandatory Quarantine or Isolation Used to Control Outbreaks?
Under the Public Health Service Act of 1944, the federal government has the authority to mandate a quarantine (to restrict movement of people exposed to a communicable disease but who show no symptoms) in response to an infectious disease outbreak. Communicable diseases that threaten public safety as defined by Executive Order of the President include:
- Severe acute respiratory syndrome (SARS)
- Yellow fever
- Hemorrhagic fevers (such as Ebola)
- Infectious tuberculosis
- Flu viruses with pandemic potential
However, this Executive Order does not include other contagious diseases such as measles. The authority to implement quarantine resides with the CDC, “which is empowered to detain, medically examine, or conditionally release persons suspected of carrying communicable diseases.”
Quarantine at the federal level is rare. It was used on a large scale during the Spanish flu pandemic in 1918 and in 1963, when there was a suspected case of smallpox.
Who Determines Mandatory Quarantine and Isolation?
Typically, the federal government defers to state and local authorities to control outbreaksbecause large-scale quarantines adversely affect the functioning of a society. States can draft their own legal structure for quarantine powers.
States use the Model State Emergency Health Powers Act, drafted on Dec. 21, 2001, to draw up their own laws. In this model act, vaccination and quarantine powers in an emergency are given to state public health authorities. If individuals refuse vaccination, then “to prevent the spread of contagious or possibly contagious disease, the public health authority may isolate or quarantine persons who are unable or unwilling for reasons of health, religion, or conscience to undergo vaccination.”
Through this act, authorities have the power to detain individuals who do not follow orders and charge them with a misdemeanor. In most states, the authority to declare the state of emergency rests with the governor and the state Department of Health to implement it, although each state may have slightly different provisions.
Local health departments also have the authority to implement quarantine and isolation in response to communicable disease outbreaks. In Clark County, Washington, the health department had the power to request voluntary or mandatory quarantine of exposed individuals when it issued its public health emergency declaration.
Under this authority, mandated quarantine is implemented when there is a reasonable assumption that individuals will not comply with voluntary quarantine or isolation. The health department then has the power to penalize those individuals with misdemeanors if they do not comply.
Although there is legal justification to order mandatory quarantine and isolation in a communicable disease outbreak, interventions must be under the “least restrictive means” possible under public health ethical guidelines. That’s why isolation and quarantine orders were required in the Clark County measles outbreak, but it was up to infected individuals to comply by staying home.
While public health departments can legally require vaccination during a public health emergency, this measure is generally thought of as the last resort. Voluntary vaccination is the first line of defense in addition to voluntary quarantine and isolation. However, if an infectious disease outbreak did continue due to lack of compliance, mandatory vaccination, isolation and legal penalties are useful tools to control communicable diseases.
About the Author
Dr. Jennifer Sedillo is an associate professor for APU’s Public Health Program. Her training is in cellular and molecular microbiology. She has been a co-author on many peer-reviewed articles. Her dissertation research was in molecular biology of malaria. Her current research interests are in public health community outreach and food safety.