Originally published at PLoS Speaking of Medicine
In 2009, as panic struck global health systems confronted with the H1N1 flu epidemic, a familiar strategy was immediately invoked by health officials worldwide: quarantine. In Hong Kong, 300 hotel guests were quarantined in their hotel for at least a week after one guest came down with H1N1. Such measures are certainly extreme, but they do raise important questions about quarantine. How do we regulate quarantine in practice? How do we prevent this public health measure from squashing civil liberties?
Quarantine as a method of containing infectious disease might be as old as the ancient Greeks, who implemented strategies to “avoid the contagious.” Our oldest and most concrete evidence of quarantine comes from Venice circa 1374. Fearing the plague, a forty-day quarantine for ships entering the city was enacted, during which passengers had to remain at the port and could not enter the city. In 1893, the United States enacted the National Quarantine Act, which created a national system of quarantine and permitted state-run regulations, including routine inspection of immigrant ships and cargoes.
“Quarantine” must be differentiated from “isolation.” While isolation refers to the separation of people infected with a particular contagious disease, “quarantine” is the separation of people who have been exposed to a certain illness but are not yet infected. Quarantine is particularly important in cases in which a disease can be transmitted even before the individual shows signs of illness. Although quarantine’s origins are ancient, it is still a widely used intervention. For example, the U.S. is authorized to quarantine individuals with exposure to the following infectious diseases: cholera, diphtheria, infectious tuberculosis, plague, smallpox, yellow fever, viral hemorrhagic fevers, SARS, and flu. Federal authorities may quarantine individuals at U.S. ports of entry.
The history of quarantine is intimately intertwined with xenophobia. There is no question that quarantine has been frequently abused, serving as a proxy for discrimination against minorities. This was especially true in late nineteenth- and early twentieth-century America, coinciding with large numbers of new immigrants entering the country. A perfect example of the enmeshed history of quarantine abuse and xenophobia occurred in 1900 in San Francisco. After an autopsy of a deceased Chinese man found bacteria suspected to cause bubonic plague, the city of San Francisco restricted all Chinese residents from traveling outside of the city without evidence that they had been vaccinated against the plague. In 1894, confronted with a smallpox epidemic, Milwaukee forcibly quarantined immigrants and poor residents of the city in a local hospital. In these cases, quarantine served as a method of containing and controlling ethnic minorities and immigrants whose surging presence in the U.S. was mistrusted.
A more recent example stems from the beginning of the AIDS epidemic in the early 1980s. In 1986, Cuba began universal HIV testing. Quarantines were instituted for all people testing positive for HIV infection. In 1985, officials in the state of Texas contemplated adding AIDS to the list of quarantinable diseases. These strategies were considered in a state of panic and uncertainty about the mode of transmission of HIV/AIDS. In retrospect, we know that instituting quarantine for HIV would have been not only ineffective but also a severe violation of individual liberties. Early in the AIDS epidemic, some individuals even called for the mass quarantine of gay men, indicating how quarantine could be used as a weapon against certain groups, such as immigrants and homosexuals. Because of their extreme nature and their recourse to arguments about protecting public safety, quarantine laws are especially prone to abuse of the sort witnessed in these cases.
How can we prevent quarantine laws from being abused? For one thing, these laws must be as specific as possible. How long can someone be quarantined before being permitted to appeal to the justice system? In what kinds of facilities should quarantined individuals be kept? The answer to this question would depend on the illness, type of exposure, and risk of contracting the disease, but in general, places of quarantine should never include correctional facilities. How are quarantined individuals monitored? How long can they be kept in quarantined conditions without symptoms before it is determined that they pose no public health risk? Quarantine laws should be sufficiently flexible to be amended according to updated knowledge about modes of transmission in the case of new or emerging infectious diseases. Quarantine measures should not be one-size-fits-all but modified according to scientific evidence relating to the disease in question. Transparency in all government communications about quarantine regulations must be standard in all cases. Most importantly, science should determine when to utilize quarantine. In order to quarantine an individual, the mode of transmission must be known, transmission must be documented to be human to human, the illness must be highly contagious, and the duration of the asymptomatic incubation period must be known. Without these scientific guidelines, quarantine may be subject to serious and unjust abuse.
In the case of infectious diseases with long incubation periods, quarantine laws can be an effective means of containing possible epidemics. Similarly, in cases in which isolation alone is not effective in containing an infectious disease outbreak, quarantine might be useful. In the case of the 2003 SARS outbreak, measures that quarantined individuals with definitive exposure to SARS were effective in preventing further infections, although mass quarantines, such as the one implemented in Toronto, were relatively ineffective. Quarantine can become a serious encroachment on civil rights, but there are intelligent ways of regulating these laws to prevent such damaging outcomes. It is important not to confuse quarantine per se with the abuse of quarantine. At the same time, when quarantine has the capacity to marginalize certain populations and perpetuate unwarranted fear of foreigners, scientific certainty is essential before implementation.