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Information from Northwestern Health Service Regarding Swine Flu

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May 20, 2009
The worldwide publicity surrounding the recent outbreak of a new Influenza A H1N1 ("swine flu") virus has caused anxiety among the Northwestern University community. It is important to keep current events in perspective. Here are some key facts and considerations that inform the University's decision making in responding to the Influenza A H1N1 outbreak.

How Dangerous is Influenza A H1N1?

Seasonal influenza causes 30,000-40,000 deaths each year in the United States and 250,000-500,000 deaths each year worldwide, mostly in those who are very young, old, or weak (e.g., with chronic medical illnesses or suppressed immune systems). Thus, the fact that approximately 50 people worldwide have died of the current Influenza A H1N1 outbreak does not in itself mean that this new virus is unusually dangerous.

Perhaps the most compelling comparison when considering the current Influenza A H1N1 outbreak is whether this new virus is behaving more like seasonal influenza vs. the highly feared avian influenza (bird flu) that has been in the news over the past 4-5 years. The latter virus has not demonstrated significant person-to-person spread, but it has proven to be highly lethal with well over 50% of those with the disease dying from it.

So, how does the Influenza A H1N1 virus compare to seasonal influenza versus avian influenza in terms of severity or lethality? Initial news reports from Mexico indicated large numbers of deaths from Influenza A H1N1, but many of these Influenza A H1N1 deaths have not been subsequently confirmed. Moreover, as more and more asymptomatic or mildly symptomatic cases have been identified, it appears that death is not a common outcome. Thus, based on the latest data, the current Influenza A H1N1 virus looks more like seasonal influenza than avian influenza. There are other biologic indicators as well that suggest this is the case. However, as will be discussed below, influenza viruses may change rapidly, and today's mild virus might become more virulent or severe in the future.

In summary, as more and more data has been acquired, at least at the present time, the illness caused by the new Influenza A H1N1 virus appears no more dangerous than seasonal influenza.

Geographic Spread vs. Virulence/Severity/Lethality

It is important to understand the distinction between contagiousness or geographic spread versus virulence/severity/lethality. While this new Influenza A H1N1 virus is spreading rapidly (which is why the World Health Organization-WHO-is worried about a pandemic), that fact alone is not sufficient to understand the threat. An equally, if not more important, question is whether this particular virus is especially dangerous, as discussed above. Unfortunately, many people confuse the WHO and CDC pandemic levels which refer to geographic spread with severity or lethality. A worldwide outbreak (pandemic) of a mild flu is quite different than a worldwide outbreak of a highly virulent and lethal flu.

Insofar as the WHO and CDC are increasingly finding that the virus, at least at this time, is mild, there is no reason to feel more concern about the Influenza A H1N1 virus than one would for the seasonal influenza that occurs every year.

Virus Transformation

Influenza viruses are well known for their ability to change over time. Through recombination with other viruses, mutations, and other mechanisms, they constantly evolve so as to elude host defenses. Thus, while the Influenza A H1N1 virus appears mild in severity at this time, it could change and become more dangerous. Soon it will be winter in the southern hemisphere, which is prime flu season, and the virus might change in this setting so as to become more dangerous. Moreover, previous influenza pandemics have typically occurred in 2-3 month waves, often with the initial wave presenting with mild symptoms only to become more dangerous and lethal in subsequent waves. No one can predict whether or how this Influenza A H1N1 virus may change over time, so, as the WHO and CDC have repeatedly cautioned, vigilance remains important. Nonetheless, given the mild nature of the vast majority of the illnesses identified thus far, there is no reason for panic or overreaction at this time.

Influenza A H1N1 at Northwestern

At least one case of Influenza A H1N1 infection has been confirmed on the Northwestern University campus, and it is likely that other cases have occurred and will continue to occur. The virus is here and it is unlikely to disappear any time soon. Indeed, Influenza A H1N1 has been identified in 48 states as of the time of this writing. On the other hand, the symptoms of flu-swine or otherwise-are general, and the majority of people with fever, sore throat, cough, runny nose, and other symptoms likely do not have Influenza A H1N1 infection. Not only can non-influenza viruses and bacteria cause similar symptoms, but data from a local hospital indicate that 80% of people in the Evanston community who have recently been tested for flu have seasonal-not Influenza H1N1-influenza.

University Response

Given these facts, how is the University responding to the Influenza A H1N1 outbreak? In summary, the University is following CDC recommendations. However, it is important to note that this situation has been very fluid, with rapid changes in recommendations on the part of the CDC as new information has become available. Thus, CDC recommendations from even 2 weeks ago have been changed and, for the most part, downgraded in terms of urgency and interventions. If some of the University responses described below appear less than expected given newspaper and other reports, it is likely to be because the virus has appeared less dangerous than initially feared and the CDC's recommendations have become more conservative.

Testing

Whereas at the beginning of the Influenza A H1N1 outbreak the CDC recommended testing for all those who were considered "suspect cases," it no longer recommends routine testing for those who might have Influenza A H1N1 or been exposed to it. As noted above, the virus is already widespread, and it is already on the Northwestern University campus. As a result, the CDC only recommends specific Influenza A H1N1 testing for those who have "atypical" symptoms or those who at risk for dangerous complications (see below). A physician's recommendation that no Influenza A H1N1 testing occur for an otherwise healthy person with flu-like symptoms is consistent with current CDC guidelines. Nonetheless, the University Health Service will provide Influenza A H1N1 testing for any student who requests it (although the cost must be borne by the student and ranges from $120 to over $300 depending on the test selected).

Isolation

Many have asked about University plans to isolate students with possible Influenza A H1N1 infection who live on campus. It is important to understand that as health officials have increasingly found the new Influenza A H1N1 virus to be less severe-more seasonal influenza-like than avian influenza-like-than initially thought, recommendations for isolation and school closures have changed. After all, few would suggest school closure or sending home every residential university student who merely had "the flu" as occurs seasonally. Thus, CDC and local public health officials are now much more conservative about recommending school closure. Similarly, most ill students need not leave school, but, instead, can be isolated in their dormitories or residence halls. Excellent information from the CDC as to how to care for oneself or others with influenza can be found through the following web links:

What to Do If You Get Flu-Like Symptoms: http://www.cdc.gov/h1n1flu/sick.htm
Taking Care of a Sick Person in Your Home: http://www.cdc.gov/h1n1flu/guidance_homecare.htm

For those students who should isolate themselves in their residence halls or other community living quarters, a variety of strategies can be used to ensure adequate nutrition and to lessen the risks of shared bathroom use.

Antiviral Medications

Again because the current Influenza A H1N1 virus appears less dangerous than initially thought, the CDC has also modified its recommendations about the use of antiviral medications such as Tamiflu and Relenza. Guidelines no longer recommend routine use of antiviral medications for those exposed to the illness or even those with proven Influenza A H1N1 infection. However, treatment with antiviral medications may be appropriate for those individuals at increased risk for complications of influenza (see below).

It is important to understand the reasoning behind these new recommendations. While Tamiflu or Relenza may be used for seasonal influenza, the vast majority of seasonal influenza sufferers do not use such medications and, instead, employ conservative measures such as bed rest, fluids, and analgesics for pain. In addition, Tamiflu and Relenza are in short supply in many pharmacies, and they are expensive and may cause a variety of side effects. The protection afforded by such medication is short-lived once the medication is discontinued. These issues, however, are perhaps overshadowed by a greater concern: viral resistance. Public health authorizes worry that unnecessary use of antiviral medication now will result in Influenza A H1N1 resistance. If so, the medications may be ineffective if the virus becomes more dangerous, precisely the time when effective medications would be most needed.

Once again, however, any student whose individual health history suggests that he or she may be at increased risk for Influenza A H1N1 (or other types of influenza) complications should speak with a Health Service clinician to determine if antiviral medication is appropriate.

Announcements

There have been many questions as to if, how often, and in which particular situations the University will notify others of additional cases of Influenza A H1N1. As already noted, there is no longer any question as to whether Influenza A H1N1 is on campus: it is here and there is every reason to suspect that more cases have already occurred and will occur in the future. While the University community was notified of the first case on campus, because the current Influenza A H1N1 virus is behaving mostly like seasonal influenza, the University does not plan to send a University-wide announcement each time a case is confirmed. Given that testing for Influenza A H1N1 is no longer routinely recommended by the CDC, notification of particular identified cases might be misleading by implying that no other cases were on campus. Thus, at least at the present time, the University will make decisions regarding notification of future Influenza A H1N1 cases on an individual basis; and, if notification is warranted, it may be general or it may be limited to specific exposed populations.

Individuals at Increased Risk

While currently the new Influenza A H1N1 virus appears less dangerous than initially suspected, some individuals may nonetheless be at high risk for complications. According to the CDC, such high risk students on a university campus are likely to be those who are:

Less than 18 years of age and receiving long-term aspirin therapy
Pregnant women
Those with chronic pulmonary, cardiovascular, hepatic (liver), hematological (blood), neurologic (nervous system), neuromuscular, or metabolic disorders (e.g., hormonal disorders like diabetes)
Immunosuppressed (including immunosuppression caused by medications or by HIV)

High-risk students should contact the Health Service about concerns regarding Influenza A H1N1, including whether testing and treatment with antiviral medications are warranted.

Health Services

Typically, more than 50% of appointments at the University Health Service are same-day appointments, meaning that a student calls in the morning and an appointment is scheduled for that same day. This, however, has not been the case recently as a result of the concern generated by the Influenza A H1N1 outbreak. The University Health Service is operating to the best of its capacity, but there will invariably be students and parents disappointed that immediate care is not always available, especially in the current circumstances. Please remember that all ill students will be seen if necessary the same day they call, but if no appointments are available, they may have to wait for an opening with the on-call physician. Yes, this is less convenient than a scheduled appointment, but the Health Service does not have unlimited surge capacity for unexpectedly high student requests. In addition, for some students with flu-like symptoms a telephone call with a nurse or physician may be sufficient and thus provide more openings for those students who need to be seen urgently at the Health Service.

Appropriate Concern and Vigilance

The Influenza A H1N1 situation remains fluid. Current thinking and guidelines may change as more information comes to light or the virus changes its character. The University will continue to stay abreast of WHO, CDC, and local public health authority recommendations, but it is important to remember that today's responses may be different than tomorrow's as the situation evolves. Nonetheless, Northwestern will continue to provide sound information, advice, and diagnostic or treatment decisions related to Influenza A H1N1.