Just How Effective Are Quarantines?

photo by Jason Scragz via Flickr 

Quarantines have been a part of America’s federal doctrine since 1878, and have occasionally throughout history drawn the ire of activists and public health officials. But, controversy aside, the question remains: just how effective are they?

Though rare, quarantines have been used throughout history following pandemics like the Spanish Flu, SARS, and more recently Ebola. To say the least, their implementation can be quite divisive. Sometimes such quarantines have been pitted as a fever vs. fervor battle, where fear of a particular illness overrides logic and even empirical science.

Their occurrence, however rare, still continues. But just how effective have they been in fighting pandemics and other ailments?

Quarantine and pandemics

Quarantine vs. Isolation

Though these two terms are used interchangeably, the CDC defines them with a slight variation. While Quarantine restricts the movements of people who may have been exposed to a disease, isolation takes those who are already sick and separates them.

When quarantine works

When the Spanish Flu ravaged the world, infecting 500 million people worldwide, people’s day-to-day lives came to a screeching halt. By the time the pandemic had settled, the dangerous strain of influenza would account for 50 million deaths worldwide.

But despite this widespread devastation, one American city–St. Louis–found a way to battle the pandemic.

Through quarantine and isolation tactics like closing schools, public transit, and populated public areas, St. Louis effectively escaped the 1918 Flu Epidemic with a mortality rate that was 70 percent below the national average.

Conversely, those cities who were retroactive in their quarantine like Philadelphia, saw a limited effectiveness with only a 28 percent reduction in mortality following quarantine and isolation measures.

Studies by Dr. Howard Markel, director of the University of Michigan Center for the History of Medicine, indicate that it was this tactic of ‘social distancing’ that helped control the spread of the Spanish Flu.

Though other quarantines have been contemplated in the U.S.–namely during the 2003 SARS scare–the Spanish Flu remains as one of the most reliable case studies to date.

Controversy and ineffectiveness

In recent history, there may be no greater example of when fervor over an illness overrode empirical science than the AIDS epidemic in the 1980’s. Though no widespread quarantines were instituted in the U.S., Cuba was quick to quarantine those exhibiting symptoms.

In 1986, under the power of national law, Cuba instituted a nationwide quarantine on those exhibiting AIDs like symptoms, much to the chagrin of LGBT communities in the U.S. who were also facing discrimination.

As recently as 2001–though the federal mandate of quarantine ended in 1993–AIDS positive patients were quarantined in sanatoriums where they were forced to stay unconditionally.

Since then, Cuba has developed a strict plan for fighting the spread of AIDS. Their approach couples policies like the widespread distribution of condoms and stringently tracing the sexual partners of AIDS positive citizens, as well as graphic sex education in schools.

The empirical approach to understanding and treating AIDS patients has led Cuba to become an infection rate of just .01 percent in 2012–one of the world’s lowest rates.

The takeaway

Empirical research has indicated that quarantines can be an effective, if controversial, method of containing widespread illness, however, their applicability should be decided on a case-by- case basis.

According to key research, some elements necessary to making the decision on when quarantines should be instituted include:

  • Efficient identification of those who are likely infected
  • Those quarantined comply to their isolation
  • The disease is contagious in it’s presymptomatic or early symptomatic stage

If these elements aren’t present, researchers warn that quarantines may by not only ineffective, but detrimental to the infected.

As per the recent Ebola scare, quarantine methodology is more or less being developed on the fly, as researchers and public health officials are attempting to determine the correct amount of quarantine time.

We measure success by the understanding we deliver. If you could express it as a percentage, how much fresh understanding did we provide?
James Pero