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Study: Quarantines Work Against Pandemics

Sally Furniss

Well-known member
Study: Quarantines Work Against Pandemics

http://www.time.com/time/health/article/0,8599,1650634,00.html?xid=rss-topstories

On the medical front, the U.S. has never been particularly good at prevention. The tack, usually, is to patch people up as they get sick, rather than keeping them from falling ill to start. But no Band-Aid is sufficient to handle a lethal pandemic, which some experts say is inevitable ? if not imminent. Whether it's bird flu or some other deadly knock-out germ that eventually sweeps through the country, scientists and public-health researchers are trying to prepare for it now to ensure that everyone has a better chance of survival.

To plan for the future, researchers in Michigan went straight to the past. Led by Dr. Howard Markel, director of the University of Michigan Medical School's Center for the History of Medicine, a team of public-health experts evaluated the U.S. response to the world's last great pandemic ? the Spanish flu in 1918. The new report, published in the Aug. 8 issue of the Journal of the American Medical Association, analyzed the public-health measures taken by 43 U.S. cities, all with populations greater than 100,000, during the six months between Sept. 1918 and Feb. 1919. Markel found that cities that early on adopted "old-fashioned," non-pharmaceutical interventions ? such as school closures, social-distancing in the community and workplace and quarantine ? and "layered" multiple interventions at once for a long period of time fared better than other cities, with slower rates of infection and lower rates of death.

"The conventional wisdom had been that cities [in 1918] had done everything they could and nothing worked ? it was all doom and gloom and dread and nothing to do but throw up our hands in despair," says Dr. Martin Cetron, director of the Division of Global Migration and Quarantine at the Centers for Disease Control and Prevention (CDC), and a senior author of the study. "This study gives us real reason for optimism, that even reaching back to a time where there were no antiviral medications and no well-matched vaccines to fight a pandemic, the things communities did in terms of traditional public health tools ? isolation, quarantine, social-distancing, canceling schools ? made a big difference and have a lot of potential to mitigate the severity of a lethal disease pandemic."

That's good news, considering that the U.S. has purchased only 26 million doses of the newly licensed H5N1 flu vaccines, enough to cover 13 million people in the event of a pandemic ?but there's no guarantee that H5N1 will even be the bug in question. In 1918 the Spanish flu infected 20% of the world's population and killed 40 million people (a mortality rate of 2.5%), and 550,000 of those deaths were in the U.S. What the new study illuminates is the small print behind that big number: some cities got hit much harder than others, and there's a lot to be learned from the way they each responded to the same threat.

Markel and colleagues divided the cities' interventions into three major categories: school closure, cancellation of public gatherings, and isolation and quarantine. During the 24 weeks researchers studied, there were 115,340 excess deaths due to pneumonia and influenza in 43 states, with a collective population of about 23 million. New York City responded to its earliest sign of infection with isolation and quarantine over a sustained period of time, beginning 13 days after the first case was detected, and had the lowest pandemic-related death rate of any city on the East coast. By contrast, Pittsburgh reacted late, waiting one month, and suffered the greatest number of excess deaths from the disease. In both cities, however, interventions were used singly rather than as a combined approach. St. Louis layered its interventions, using the various social-distancing measures at once, 2.5 weeks after its first case of infection; that tactic mitigated the outbreak and St. Louis fared better than 36 other communities as a result. Researchers compare layering interventions to layering Swiss cheese: if the holes are vulnerabilities, with enough layering you'll end up with a solid block of prevention.

Though Markel's study has just been published, it has already been rolled into policy. The Department of Health and Human Services and CDC finished their analysis of the study's data last December before incorporating it into the Community Strategy for Pandemic Influenza Mitigation, a collection of guidelines for use by individuals and communities issued by the agencies in February. The guide offers help in coordinating and implementing a strategy to protect communities from the front end of an epidemic and to keep them afloat until the appropriate pandemic-strain vaccine can be delivered to them ? which officials estimate will be four to six months after the first case is identified

The context of the 21st century, however, is very different from that of 1918. Individual rights are guarded a lot more fiercely today than in the past, and people may not submit easily to compulsory quarantine or isolation. It is critical that if we were to implement such public health measures that we have adequate medical and psychological support, says Markel. "If you come down with the force of the law very hard, you have to ask if the public health edict helps public health or endangers it," he says. "The onus is on us as physicians, public health experts, government public health officers at the city, state and federal levels to embark on a huge educational campaign."

These days, too, travel ? and spread of disease ? is faster, but so is communication. The medical community can share information more quickly. Accordingly, there's more pressure for better and faster detection of infection. "Early needs to be earlier because things move much more rapidly," says Cetron. "It means not waiting until that death curve doubles. We want the trigger to be the first outbreak or cluster of cases of the pandemic strain in a community or state."

He adds: "We're probably the first generation in history to have the benefit of hindsight and time to plan for the future, not only to implement the measures effectively but to plan for the adverse unintended consequences of social-distancing strategies," says Cetron. Now that sounds a lot like prevention.
 
Re: Study: Quarantines Work Against Pandemics

http://www.flutrackers.com/forum/showthread.php?t=31963
Study: Quarantines Work Against Pandemics
http://www.time.com/time/health/arti...rss-topstories
....
The context of the 21st century, however, is very different from that of 1918. Individual rights are guarded a lot more fiercely today than in the past, and people may not submit easily to compulsory quarantine or isolation. It is critical that if we were to implement such public health measures that we have adequate medical and psychological support, says Markel. "If you come down with the force of the law very hard, you have to ask if the public health edict helps public health or endangers it," he says. "The onus is on us as physicians, public health experts, government public health officers at the city, state and federal levels to embark on a huge educational campaign."

from link above
http://www.flutrackers.com/forum/showthread.php?t=14031
Also, the nation is now technologically and socially different than it was in 1918, and factors like better transportation and shopping malls might cause a pandemic to play out differently, said Dr. D.A. Henderson, a biosecurity expert at the University of Pittsburgh Medical Center.

Dr Cetron may begin by a case review of their recent efforts to isolate one case of TB.
http://www.usatoday.com/news/health/2007-06-01-700555388_x.htm

Yes, if they are counting on quarantines, then a huge educational campagin for policy makers is necessary.
JT
 
Re: Study: Quarantines Work Against Pandemics

.....
Yes, if they are counting on quarantines, then a huge educational campaign for policy makers is necessary.
JT

And a similar public education program for a public which will want to exercise its freedom of choice in times of quarantine and isolation.
 
Re: Study: Quarantines Work Against Pandemics

they don't say, how much these measures might help :-(
Looking at the 1918-numbers it seems that you can't expect much
more than halfing the deaths
 
Re: Study: Quarantines Work Against Pandemics

Community Measures Prevent Deaths During Pandemic, New Study Finds

http://www.cdc.gov/od/oc/media/pressrel/2007/r070807.htm

School closures and other community strategies designed to reduce the possibility of spreading disease between people during an epidemic can save lives, particularly when the measures are used in combination and implemented soon after an outbreak begins in a community, according to a new study based on public records from the 1918-1919 influenza pandemic.

The findings, which are published in the Aug. 8 issue of the Journal of the American Medical Association, provide vital clues to help public officials planning for the next influenza pandemic and highlight the importance of community strategies. These strategies are particularly important because the intervention most likely to provide the best protection against pandemic influenza -- a vaccine -- is unlikely to be available at the outset of a pandemic. Community strategies that delay or reduce the impact of a pandemic (also called non-pharmaceutical interventions) may help reduce the spread of disease until a vaccine that is well-matched to the virus is available.

Scientists from the Centers for Disease Control and Prevention (CDC) and the University of Michigan Medical School′s Center for the History of Medicine completed an exhaustive review of public records such as health department reports, U.S. Census mortality data and newspaper archives.

"Communities that were most successful during the 1918 pandemic quickly enacted a variety of measures," said Dr. Martin Cetron, director of CDC′s Division of Global Migration and Quarantine and senior author of the study. "Those planning for the next pandemic need to carefully consider how to best use these strategies to protect people and decrease the potential impact of the next pandemic in their communities."

These strategies ? voluntary isolation and quarantine, dismissal of students from school classrooms, and social distancing in the workplace and community ? form the basis for CDC?s guidelines for how American communities can empower themselves to confront the next influenza pandemic.

The JAMA study evaluated public health measures such as school closures and cancellation of public events, which 43 American cities took during the 1918 pandemic. The researchers sought to determine whether the timing, duration and combination of such measures impacted the city′s death rate during the pandemic.

To determine the public health measures′ effectiveness, the researchers analyzed each city′s excess death rate - the number of pneumonia and influenza deaths in excess of the amount expected for the time period.

During a 24-week period in 1918-1919, more than 115,000 excess pneumonia and influenza deaths in the 43 cities were attributed to the pandemic. Cities that began interventions earlier had more success in decreasing excess deaths than those that implemented the measures later, regardless of how long the later interventions were in place or how they were executed.

In a telling example, New York City′s early and sustained response, including isolation and quarantine and staggered business hours, resulted in the lowest excess death rate for any city on the East Coast during the time period reviewed. By contrast, Pittsburgh was well into its outbreak before implementing the interventions and experienced the highest excess death rate of any of the 43 cities.

"In a world faced by the threat of avian influenza or other novel strains of influenza, it is critical to determine if such costly and socially harsh measures as school closures and cancellation of public gatherings might not only lower death and case rates, but also delay the spread and allow time for the development and distribution of effective vaccines and antivirals," said Dr. Howard Markel, director of the University of Michigan Medical School′s Center for the History of Medicine and lead author of the study. "We have demonstrated that these measures can have a real impact."

The interventions assessed fell into three major categories: school closures, bans on public gatherings and isolation of sick people and quarantine of their healthy household contacts. The most common approach was closing schools combined with banning public gatherings. All but three of the 43 communities closed schools during the 24-week period studied.

Influenza pandemics occur when a new influenza virus emerges to which most people have little or no immunity and the virus gains the ability to spread easily between people. The 1918 pandemic sickened about 20 percent of the world′s population and caused an estimated 40 million deaths worldwide, about 550,000 of them in the United States.
 
Re: Study: Quarantines Work Against Pandemics

Does quarantine work for pandemic flu?

Category: Bird flu ? Pandemic preparedness ? Public health preparedness
Posted on: August 9, 2007 7:02 AM, by revere

We've written here frequently about the ineffectiveness of quarantine for stopping the spread of influenza, but now a piece comes out in the Journal of the American Medical Association (JAMA) that claims quarantine was an effective mitigation method for influenza in 1918. Time Magazine, for example, had an article with the headline: "Study: Quarantines Work Against Pandemics":

To plan for the future, researchers in Michigan went straight to the past. Led by Dr. Howard Markel, director of the University of Michigan Medical School's Center for the History of Medicine, a team of public-health experts evaluated the U.S. response to the world's last great pandemic -- the Spanish flu in 1918. The new report, published in the Aug. 8 issue of the Journal of the American Medical Association, analyzed the public-health measures taken by 43 U.S. cities, all with populations greater than 100,000, during the six months between Sept. 1918 and Feb. 1919. Markel found that cities that early on adopted "old-fashioned," non-pharmaceutical interventions -- such as school closures, social-distancing in the community and workplace and quarantine -- and "layered" multiple interventions at once for a long period of time fared better than other cities, with slower rates of infection and lower rates of death. (Time)
Naturally I was curious about the basis for this, so I retrieved the article (subscription only, alas) by Markel and his colleagues. Examination of mortality data, week by week, in 43 cities showed great variation. Markel et al. wondered if the measures taken to stem the epidemic could account for the differences. They classified the non pharmaceutical interventions (NPIs) into three broad categories: school closures; bans on public gatherings; isolation and quarantine and looked at timing and timeliness as well as combinations of NPI categories for effects on excess mortality, height of epidemic peak and timing of epidemic peak, using multivariate analysis. One problem is that isolation and quarantine were grouped together, although they are quite different. Isolation is segregation of those who are already sick, while quarantine is segregation of those who are well but have had exposure to those who are sick. The only example given of true quarantine was in New York City where the sick were isolated and their contacts confined to their homes, which were placarded. New York City was one of the earliest to act and one most vigorous enforcers of NPI and was said by Markel et al. to have suffered less than other cities, at least by official records. John Barry in his book The Great Influenza (p. 276) suggests NYC suffered severely and many cases were just not recorded. In any event, in this case, too, it is not possible to disentangle the separate effects of isolation and of quarantine.

What is quite clear from the analysis, however, is that information about when, how long and in what combination NPIs were used in relation to the onset of the epidemic in a city explains a great deal of the variation in epidemic experience. Every city did something (i.e., adopted a measure from at least one of the three categories). 15 out of 43 used all three concurrently. The most common combination was school closure and bans on public gatherings (79%) for a median duration of 4 weeks (range 1 - 10 weeks). The most common single intervention was school closure (93%), but New York City, New Haven and Chicago never closed their schools, even in the face of widespread absenteeism (more than 45% at one point in Chicago). Several cities closed their schools more than once. The median time of school closure was 6 weeks (range 0 - 15 weeks).

The analysis showed that combinations were more effective than single interventions. This may be a correlate of how seriously the city was taking the epidemic or a real effect of the interventions themselves. But it also showed that there were features of individual cities that made a difference (the NPI x city interaction term was significant), although what about the cities modified the effect is not known. None of population size, density, sex distribution or age distribution accounted for differences in mortality. Many cities suffered several waves of the pandemic, but there was no association between severity in one wave with that of another.

The bottom line is that the earlier a city acts and the more coordinated and multifaceted its response the better off it seemed to be -- in general. The data certainly do not demonstrate that quarantine itself is effective -- they are not able to make that statement. Cities that acted using isolation and quarantine did seem to do better, especially if in combination with other measures, but we don't know the effectiveness of either separately or in combination since they were not reported or analyzed separately in the paper.

What these data do seem to establish is that the better prepared and organized a community is, the better off it will be. And the more a community ignores and denies a problem, the worse off it will be. This is the real message, not that "quarantines work."

But you knew that.

http://scienceblogs.com/effectmeasure/2007/08/does_quarantine_work_for_pande.php
 
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