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  • Mexican swine flu victims were young, some healthy

    Source: http://www.reuters.com/article/gover...090629?sp=true

    Mexican swine flu victims were young, some healthy
    Mon Jun 29, 2009 5:00pm EDT

    * Most patients were under age 59

    * All hospitalized patients had pneumonia

    * No single pattern predicts sickest patients

    By Maggie Fox, Health and Science Editor

    WASHINGTON, June 29 (Reuters) - Swine flu patients in Mexico were young and many were healthy before developing severe infections, doctors reported on Monday.

    The first detailed studies of the outbreak of a new strain of H1N1 influenza show the epidemic in Mexico resembled the early stages of other pandemics, and showed there is no way yet to predict who will become severely ill from the virus.


    The World Health Organization has confirmed 70,893 cases in the new H1N1 swine flu pandemic, with 311 deaths. However, U.S. health officials last week said there were likely at least a million cases there alone. Iraq, Lithuania, Monaco and Nepal all confirmed their first cases on Monday.

    Dr. Rogelio Perez-Padilla of the National Institute of Respiratory Diseases in Mexico City and colleagues studied 18 H1N1 cases in March and April, more than half of them aged 13 to 47.

    Only eight had pre-existing medical conditions that might worsen their flu infection, they wrote -- including high blood pressure, diabetes, asthma and sleep apnea. Seven died -- all of multiple organ failure.

    The doctors said 90 percent of the seriously ill patients were under 50 -- in contrast to seasonal influenza, which causes mostly mild illness in people under the age of 65.

    "Most of our patients were young to middle-aged and had previously been healthy," they wrote in their report, published in the New England Journal of Medicine.

    "One contributing factor for death in our patients may have been delayed admission and delayed initiation of oseltamivir."


    Oseltamivir, sold by Roche AG (ROG.VX) under the brand name Tamiflu, can treat influenza, although Denmark reported the first case on Monday of swine flu resisting the drug's effects. [ID:nLT265113]

    "We did not find a factor that, before the onset of illness, predicted a worse outcome or death among our patients," Perez-Padilla's team wrote.

    HEALTHCARE WORKERS

    In addition, 22 of 190 healthcare workers who came close to the patients themselves got flu-like illness but were treated with Tamiflu and none got seriously ill.

    Dr. Stefano Bertozzi of the National Institute of Public Health in Mexico and colleagues studied the cases of 2,155 people who developed severe pneumonia from H1N1 infection in March and April, 821 who had detailed hospital records and 100 who died.

    They found that 87 percent of those who died were aged 5 to 59, and 71 percent of severe cases were among people 5 to 59, compared to a usual average of 32 percent for seasonal flu.

    "This wave of pneumonia is reminiscent of the initial phase of pandemics from the last century," they wrote.


    Health experts have speculated that people over the age of 52 have some protection from the new virus because it may resemble a strain of H1N1 flu that circulated before 1957.

    "Influenza A H1N1 abruptly disappeared from humans in 1957 and was replaced by a new reassortant virus that combined genes from the H1N1 strain and an avian virus," Dr. Shanta Zimmer and Dr. Donald Burke of the University of Pittsburgh wrote in a second report in the same journal. Flu viruses frequently swap genes in a process called reassortment.

    (Editing by Vicki Allen)

  • #2
    Re: Mexican swine flu victims were young, some healthy

    Source: http://www.cidrap.umn.edu/cidrap/con...9h1n1nejm.html


    Novel H1N1 flu can cause severe respiratory illness

    Maryn McKenna * Contributing Writer

    Jun 29, 2009 (CIDRAP News) ? Novel H1N1 influenza can cause severe respiratory illness, profound lung damage, and death even in patients with no underlying conditions to make them vulnerable, a team of physicians from Mexico report in a rush article published online today by the New England Journal of Medicine (NEJM).

    The analysis of 18 patients hospitalized with H1N1 (swine) flu at the National Institute of Respiratory Diseases (INER) in Mexico during the pandemic's earliest days reveals that fewer than half had underlying medical conditions, but more than half needed mechanical ventilation within a day of admission. Seven of the 18 died.

    In a companion article, also published in advance online today, a multi-national team from Mexico and the United States document the age distribution of the first month of the H1N1 pandemic in Mexico, where the disease appears to have struck first, and confirm its unusual pattern of severe pneumonia among younger patients. Matching the pattern to those of earlier pandemics, the team speculates on the "biologic plausibility of partial protection" in older people exposed to mid-20th century strains of seasonal flu.

    The case series of 18 patients, written by researchers from INER, the Mexican Secretariat of Health and BIRMEX, Mexico's state-owned vaccine-production laboratories, documents the severe illness of the first patients admitted with lab-confirmed H1N1 infection and x-ray?confirmed bilateral pneumonia during the pandemic's first wave.

    The 18, of whom 7 died, are a subset of 98 patients hospitalized at the institute with pneumonia or influenza-like illness between March 24, the presumed onset date of the first known case, and April 24. Those 98 were a subset of 214 patients who came to the institute's emergency room with influenza-like illness or severe respiratory distress.

    The 18 patients were evenly divided by gender but ranged widely in age, from 9 months to 61 years, with a median age of 38. They were all at least moderately ill, with fever of at least 38?C (100.4?F), cough, and difficulty breathing; 4 of the 5 children had diarrhea.

    Most had bloodwork findings that indicated acute viral infections, inflammation and cardiac distress. Half had low blood pressure that persisted after emergency treatment, and 10 of the 18 needed to be put on ventilators within 24 hours of arrival at the hospital.

    Eight of the 10?5 of the 11 survivors and 3 of the 7 who died?had a pre-existing medical condition: asthma, sleep apnea, diabetes, or high blood pressure. (In the United States, "The vast majority of the fatalities ? do occur in people with underlying conditions," Dr. Anne Schuchat of the Centers for Disease Control and Prevention said in a press briefing Friday. "It's not 100%. It's more on the on order of three-fourths.")

    "We did not find a factor that, before the onset of illness, predicted a worse outcome or death among our patients," the researchers said.

    In a finding that is likely to fuel an ongoing debate, the researchers found that none of the 18 patients had concomitant bacterial pneumonia, a finding that has been replicated in the United States and that differs from cases recorded during the 1918 pandemic. However, 9 of the survivors and 4 of the deceased received antibiotics during outpatient visits before they reached the institute, and 17 were given antibiotics after admission there, making it unlikely that any bacterial infection would be discovered.

    Fourteen of the 18 received the antiviral drug oseltamivir (Tamiflu), either at admission or within a few days of being admitted?in all cases, many days after the 2-day window when flu antivirals are most likely to have an effect.

    The patients had a difficult course, with renal failure in 1 survivor and 5 of the deceased and multi-organ failure in all 7 of the dead. Pathological examination of the lungs of one of the dead patients showed severe damage to lung tissue, but, with no bacterial infection evident, the researchers ascribed it to the primary viral pneumonia caused by the new flu. No evidence was found of co-infection with any other virus.

    And as evidence of the way the novel H1N1 took Mexico and the world by surprise, the researchers found that the 18 patients passed the flu to their families, with 82 people potentially exposed and 20 ill. Four required hospital treatment, and 1 died. Plus, 22 of the 190 healthcare workers who came in contact with the first 3 patients admitted to the institute also came down with the novel flu, but were sent home with oseltamivir and were only mildly ill.

    Like the first set of patients, the healthcare workers and family members who fell ill in the second generation of cases were primarily younger, a situation mirrored in the second paper published today in NEJM. The analysis is by scientists from Arizona State University, the University of California, Berkeley, and the US National Institutes of Health, along with the Mexican Ministry of Health and National Institute of Public Health.

    They found that, out of 2,155 reported cases of severe pneumonia and 2,582 lab-confirmed samples of the new flu submitted in Mexico during the pandemic's first month, 71% of severe pneumonias and 87% of deaths occurred in those between the ages of 5 and 59. That pattern is unlike any observed during seasonal flu in Mexico but matches records from the three pandemics of the 20th century, they said.

    Perez-Padilla R, de la Rosa-Zamboni D, Ponce de Leon S et al. Pneumonia and respiratory failure from swine-origin influenza A (H1N1) in Mexico. N Engl J Med 2009 (published online Jun 29) [Full text]

    Chowell D, Bertozzi S, Arantxa Colchero M et al. Severe respiratory disease concurrent with the circulation of H1N1 influenza. N Engl J Med 2009 (published online Jun 29) [Full text]

    Comment


    • #3
      Re: Mexican swine flu victims were young, some healthy

      #2:
      ""We did not find a factor that, before the onset of illness, predicted a worse outcome or death among our patients," the researchers said.

      In a finding that is likely to fuel an ongoing debate, the researchers found that none of the 18 patients had concomitant bacterial pneumonia, a finding that has been replicated in the United States and that differs from cases recorded during the 1918 pandemic."

      Comment

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