Tuesday, August 11, 2009

NY Times review: Seeking Lessons in Swine Flu Fight

Seeking Lessons in Swine Flu Fight

New York Times: August 10, 2009

Much about the swine flu pandemic and the virus remains unknown...

  • This outbreak exposes many weaknesses in world’s ability to respond to the sudden emergence of a widespread illness.
  • Over all, the pandemic’s severity is considered as “moderate” compared with past influenza pandemics, but the WHO says, it's spread with “unprecedented speed” > 168 countries.
  • Typically flu strikes in colder months, but the swine flu virus, A(H1N1), has swept through summer camps in the United States and Canada.
  • Belief that many more people will get swine flu than seasonal influenza this fall and winter, but outbreaks of both strains possible, perhaps at different times.
  • One weakness -- despite years of planning -- the infrastructure of health departments in many countries, including the United States, is inadequate (in varying degrees) to deal with the sudden appearance of a new strain of influenza.
  • Also, the number of beds in hospital intensive-care units and emergency rooms is limited, as is equipment like mechanical respirators to help patients breathe when the virus attacks the lungs.

Another problem is communication, journal reports still lacking...

  • Officials and experts say much have been learned about A/H1N1 influenza.
  • But relatively little information, including periodic summaries of what has been learned since beginning of pandemic, has been reported and published.
  • Some said researchers waiting to publish in journals, which can take months or longer.
  • Journals impose severe penalties for disclosing information before publication, although they say they exempt matters of public health importance.
  • Whatever the reason, delays in reporting such information can hamper plans for public health responses.

Unusual Presentation of A/H1N1 flu hamper quicker diagnosis/management...

Dr. Wenzel, a former president of the International Society for Infectious Diseases, said he had observed a broad spectrum of illness from human swine influenza: people who experienced few or no symptoms to those who rapidly developed complications and died.

  • The standard definition of influenza includes a fever.
  • Odd feature of new virus is the lack of fever in significant number documented cases,
  • Even in some patients become seriously ill.
  • In Chile, it was about half, in Mexico City about a third and elsewhere, less,
  • Lack of fever has been noted by other observers in several Canadian cases.

Analysis of data from specimens yet to be tested may shed light on how often infected individuals who have no fever spread the virus.

  • Epidemiologists stress need for rigorous methodology to produce the solid data -- crucial for planning.
  • A need exists to account for the several-week delay between onset of symptoms and death in influenza and other illnesses.
  • Failure to take that time lag into account can seriously underestimate the death rate, depending on when in the pandemic the information is obtained.

Atypical symptoms unhelpful in some patients...

  • So absence of fever among many patients, (when fever is specified in the definition), can cause serious underestimation of case totals.
  • Also, absence of fever limits the usefulness of thermal scans to identify people who have the virus and thus control the pandemic.
  • Diarrhea appears to be occurring in a larger percentage of cases than seasonal influenza, reinforcing the importance of frequent hand washing.
  • As yet, unclear when infected people stop shedding H1N1 virus, thus when to help stop spreading the illness.
  • This info particularly needed for those with impaired immune systems from H.I.V. infection, chemotherapy and anti-rejection drugs used in organ transplants.

Mexican doctors found A/H1N1 influenza virus on the hands of workers, on tables next to patients’ beds, on other hard surfaces and on a computer mouse, Dr. Wenzel says “infection control in hospitals must be assiduous to prevent spread, particularly those with impaired immune systems.”

  • The course of illness can become life-threatening in just a few hours among patients who had shown only mild symptoms,
  • Dr. Wenzel said, “doctors know little about what treatment works in severe cases.”
  • 2 unusual features of the new virus are that pregnancy, particularly in third trimester,
  • obesity seem to increase the risk for complications of the infection.

Dr. Anthony E. Fiore, an influenza epidemiologist at the Centers for Disease Control and Prevention in Atlanta, said that studies are under way, to clarify whether obesity is an independent risk factor for complications of influenza or whether obese people have conditions like heart disease, asthma and other chronic lung ailments that put them at such risk.

Diagnostic Testing Problems...

  • Doctors actively involved in patient care are hampered by the lack of a standard, reliable rapid test to determine if a patient has swine influenza or some other respiratory illness.
  • The diagnosis of swine influenza A(H1N1) has to be made through special tests known as P.C.R., for polymerase chain reaction.
  • The tests are used in research laboratories but otherwise are generally available only through local and state health departments.
  • The P.C.R. tests, even if offered by a commercial laboratory, generally cannot be done in time to help a doctor determine whether a patient in an office, a clinic or a hospital has seasonal or swine influenza — a factor in determining what treatment to offer.
  • Most local and state health departments under severe budget restraints.

“We are stuck diagnostically, while we have increased expectations of what public health departments can do, and the science behind it, we do not have the infrastructure to do it.”

Information still incomplete...

Dr. Schaffner said, "Health professionals and the public should be receiving more information in a timelier way about what has been learned about the swine influenza pandemic."

Speaking about some of the gaps in clinical and epidemiological details, Dr. Schaffner said that “it is worth being tough and saying how come we do not know more.”

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