No Fever, No Test?

[indigo girl]

I wanted to post these links to make everyone aware that absence of fever does not mean absence of infection with swine flu.

Some people do not have develop a fever even when they are very sick. And, it is a characteristic of swine H1N1, that not all cases are febrile.

The nurse that I worked with two nights ago, came in with sore throat, and a cough but no fever. By the end of the shift, she was very ill, and called out the next day. She never has a fever when ill, and is immuno compromised with hx of Ca x2, chemo, and thalessemia. She is also an asthmatic and a smoker. We are awaiting the results of her PCR test.

http://www.flutrackers.com/forum/showpost.php?p=279902&postcount=1

I have asked this question several times and have received no answer. Every time the CDC prints the symptoms chart for hospitalized H1N1 patients, "Fever" has an asterisk next to it, but it is never followed by a corresponding footnote!!

WHAT DOES IT MEAN?!?!??!

http://www.cdc.gov/h1n1flu/surveillanceqa.htm

(chart is in the bottom 1/4 of the above-linked page)

http://www.flutrackers.com/forum/showpost.php?p=279924&postcount=3

Actually, I believe the asterisk is there just to define "fever". Unfortunately, the absence of a fever is used to deny testing, which of course is not a good situation for those who are infected with H1N1 but don't have a fever. Reports of no fever came out of Mexico very early (30% of patients had no fever), but fever was included in the case definition in the U.S. (probably due in part because seasonal flu is usually associated with a fever). However, swine flu isn't seasonal, so including it in the case definition creates an artifact (something introduced by a person, and not a true reflection of what is being measured or analyzed).

Thus, in Mexcio City, 30% of cases have no fever, and in Chile 50% have no fever, but in the United States the CDC says 7% because without a fever patients are not tested.

Thus, in reality, the frequency of swine H1N1 infections with NO fever is almost certainly ABOVE 50%, but the lack of testing of those without fever lowers it to 30% in Mexico City and 7% in the US, but the 7% in the US is PURE artifact (and WIDELY misunderstood leading to a lack of treatment and unnecessary deaths).

http://crofsblogs.typepad.com/h5n1/2009/08/us-seeking-lessons-from-h1n1.html

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. But an odd feature of the new virus is the lack of fever in a significant proportion of documented cases, even after some patients become seriously ill. In Chile, it was about half, in Mexico City about a third and elsewhere, less, Dr. Wenzel said. 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 the need for rigorous methodology to produce the solid data that is crucial for planning. For example, a need exists to account for the several-week delay that can occur between the 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 course of the pandemic the information is obtained.

So absence of fever among substantial proportions of 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.

[indigo girl]

Many Swine Flu Cases Have No Fever

http://www.nytimes.com/2009/05/13/health/13fever.html

Published in May 2009

Many people suffering from swine influenza, even those who are severely ill, do not have fever, an odd feature of the new virus that could increase the difficulty of controlling the epidemic, said a leading American infectious-disease expert who examined cases in Mexico last week.

Fever is a hallmark of influenza, often rising abruptly to 104 degrees at the onset of illness. Because many infectious-disease experts consider fever the most important sign of the disease, the presence of fever is a critical part of screening patients.

But about a third of the patients at two hospitals in Mexico City where the American expert, Dr. Richard P. Wenzel, consulted for four days last week had no fever when screened, he said.

"It surprised me and my Mexican colleagues, because the textbooks say that in an influenza outbreak the predictive value of fever and cough is 90 percent," Dr. Wenzel said by telephone from Virginia Commonwealth University in Richmond, where he is chairman of the department of internal medicine.

While many people with severe cases went on to develop fever after they were admitted, about half of the milder cases did not; nearly all patients had coughing and malaise, Dr. Wenzel said.

Also, about 12 percent of patients at the two Mexican hospitals had severe diarrhea in addition to respiratory symptoms like coughing and breathing difficulty, said Dr. Wenzel, who is also a former president of the International Society for Infectious Diseases. He said many such patients had six bowel movements a day for three days.

Dr. Wenzel said he had urged his Mexican colleagues to test the stools for the presence of the swine virus, named A(H1N1). "If the A(H1N1) virus goes from person to person and there is virus in the stool, infection control will be much more difficult," particularly if it spreads in poor countries, he said.

The doctor said he had also urged his Mexican colleagues to perform tests to determine whether some people without symptoms still carried the virus.

He also said he had examined patients and data at the invitation of Dr. Samuel Ponce de León, who directs Mexico's national vaccination program.

Dr. Wenzel said that an unusual feature of the Mexican epidemic, which complicates the understanding of it, was that "in recent months five different influenza viruses have been circulating in Mexico simultaneously."

Pneumonia rates at one of the hospitals Dr. Wenzel visited, the National Institute for Respiratory Diseases, reached 120 per week recently compared with 20 per week during the past two years, suggesting a possible relation to the swine flu.

The pneumonias that the flu patients developed did not resemble the staphylococcal lung infections that were believed to be a common complication in the 1918-1919 influenza pandemic, Dr. Wenzel said.

He said the two Mexican hospitals were well prepared for an outbreak of respiratory disease. Mexican doctors activated a program to allay anxiety among staff members, offering the staff information, a hot line, psychological support and medical examinations.

"This aspect of epidemic response is not well appreciated in the United States in my estimation, yet is critical for success," Dr. Wenzel said. "We haven't put nearly enough into managing fear among health workers."