4월 17일~8월 22일 기간 동안 미국 캘리포니아주에서 신종플루로 보고된 1,088명 중에서 11%(118명/1,088명)가 사망했으며, 50세 이상의 고령자의 사망율(18-20 %)이 높은 것으로 드러났다는 JAMA에 실린 최신 연구결과입니다.
18세 이하의 사망율은 7%로 나타났으며, 독감 증상 발현부터 사망까지는 평균 12일이 소요되었던 것으로 나타났습니다. 사망원인은 바이러스성 폐렴 및 급성호흡곤란증후군( acute respiratory distress syndrome)입니다.
WHO의 최근 발표에 따르면 현재까지 전세계적으로 5700명 이상의 신종플루로 사망하였으며, 사망자 5700명 중 북미대륙의 사망자가 4175명으로 대부분의 사망자가 북미대륙에서 발생하였습니다.
젊은 층일수록 감염율이 높고, 노령자일 수록 사망자가 많은 미국 캘리포니아 주의 통계는 국내의 통계와도 부합되는 것 같습니다.
11월 4일 현재 국내 공식사망자 45명 중 고위험군은 37명(82%), 비고위험군은 8명(18%)이고… 사망자의 연령 분포를 보면 60대 이상 25명(56%), 50대 5명, 40대 5명, 30대 1명, 20대 2명, 10대 2명, 10대 미만 5명으로 나타났습니다.
신종플루 감염율은 보건복지부 10월 31일자 통계에 따르면, 10세 미만(25%),10대(59% ), 20대(9%), 30대(3%), 40대(2%), 50대(1%), 60대 이상(1%)로 나타났습니다. 성별로는 남성(58%)이 여성(42%)보다 다소 많았습니다.
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Factors Associated With Death or Hospitalization Due to Pandemic 2009 Influenza A(H1N1) Infection in California
출처 : JAMA. 2009;302(17):1896-1902. Objective To describe the clinical and epidemiologic features of pandemic 2009 influenza A(H1N1) cases that led to hospitalization or death. Design, Setting, and Participants Statewide enhanced public health surveillance of California residents who were hospitalized or died with laboratory evidence of pandemic 2009 influenza A(H1N1) infection reported to the California Department of Public Health between April 23 and August 11, 2009. Main Outcome Measure Characteristics of hospitalized and fatal cases. Results During the study period there were 1088 cases of hospitalization or death due to pandemic 2009 influenza A(H1N1) infection reported in California. The median age was 27 years (range, <1-92 years) and 68% (741/1088) had risk factors for seasonal influenza complications. Sixty-six percent (547/833) of those with chest radiographs performed had infiltrates and 31% (340/1088) required intensive care. Rapid antigen tests were falsely negative in 34% (208/618) of cases evaluated. Secondary bacterial infection was identified in 4% (46/1088). Twenty-one percent (183/884) received no antiviral treatment. Overall fatality was 11% (118/1088) and was highest (18%-20%) in persons aged 50 years or older. The most common causes of death were viral pneumonia and acute respiratory distress syndrome. Conclusions In the first 16 weeks of the current pandemic, the median age of hospitalized infected cases was younger than is common with seasonal influenza. Infants had the highest hospitalization rates and persons aged 50 years or older had the highest mortality rates once hospitalized. Most cases had established risk factors for complications of seasonal influenza.
http://jama.ama-assn.org/cgi/content/short/302/17/1896?homeContext
Pandemic influenza A(H1N1) emerged rapidly in California in April 2009. Preliminary comparisons with seasonal influenza suggest that pandemic 2009 influenza A(H1N1) disproportionately affects younger ages and causes generally mild disease.
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H1N1 Flu: Hitting the Young, but Riskier for the Old
출처 : Time Nov. 03, 2009
http://www.time.com/time/health/article/0,8599,1934330,00.html?xid=rss-topstories
As the number of H1N1 cases continues to climb in the U.S., researchers are collecting more and more data on the spread of the pandemic flu and getting a clearer picture of its victims — who is most vulnerable to H1N1, how the most severe cases progress and which risk factors tend to contribute to life-threatening disease. That data is now helping public-health officials identify some critical H1N1 trends, which may enable them to treat patients more effectively and hopefully control the disease as it peaks in the coming months.
(See the top five swine flu don’ts.)
The latest study, published this week in the Journal of the American Medical Association, offers a snapshot of 1,088 H1N1 cases in California that were severe enough to require hospitalization — or resulted in death — between April 23 and Aug. 11 of this year. Experts at the California Department of Public Health, who led the study, say their findings are largely in line with the growing body of data on the worldwide pandemic flu, confirming, for instance, that the 2009 H1N1 flu disproportionately affects younger patients. The California research team found that the median age of hospitalized H1N1 patients was 27, much lower than the median age of seasonal flu sufferers.
While H1N1 infection results in mild or moderate disease in most patients — indeed, the most severe cases account for a small proportion of overall infections — a subset of patients are harder hit, the data shows. And in those patients, the disease can often quickly become life-threatening. “The major point of our findings is that there has been a lot of perception that this is a mild disease, and a lot of people may be ambivalent about vaccination,” says Dr. Janice Louie, a public-health medical officer at the California Department of Public Health and the study’s lead author. “But for those patients who were hospitalized, 30% required intensive care. This is something that clinicians should be aware of when patients walk into their clinic or office with signs of flu.”
Among hospitalized patients in the study, 118 died — an overall 11% fatality rate. Although the rate of hospitalization was highest among infants under 2 months old, the rate of death was highest in patients over age 50; H1N1 was least likely to turn fatal in patients under age 17. Yet with all the focus in the media on the vulnerability of younger patients to infection, the elderly may have been somewhat dangerously overlooked, says Louie. Although older patients may not be at high risk of getting infected in the first place (thanks to their residual immunity to the virus from previous outbreaks of H1N1), their risk of death from the disease may be higher than that of younger patients, due primarily to their higher rates of underlying conditions, such as heart disease, reduced lung function, diabetes and emphysema.
Indeed, the state’s data suggest that chronic underlying conditions are among the main risk factors for developing H1N1 disease severe enough to require hospital care. In both young and old patients who were hospitalized for swine flu (741 cases in total), ailments that complicate the flu were common: some 60% of children and 72% of adults had conditions including high blood pressure, high cholesterol and gastrointestinal disease. (See how to prevent illness at any age.)
The California data also reveal a potentially new risk factor for H1N1: obesity. Obese individuals were disproportionately represented in the state’s sample of hospitalized cases — 58% of adults age 20 or older registered as obese, and 43% of these morbidly so. Those with excessive body-mass index measurements tend to have other medical conditions related to weight that may put them at risk of suffering more severe infection with H1N1. Being overweight can increase sleep apnea and reduce lung function, for example, both of which can impair a heavier person’s ability to overcome a respiratory infection like influenza. Among the 156 obese adults in Louie’s sample, 66% had underlying diseases known to complicate the flu, including chronic lung disease, heart disease and diabetes.
But what’s baffling, say the study’s authors, is that obesity does not stand out as a risk factor in severe cases of seasonal influenza. “A lot of us are puzzling over this, because this is not a trend with seasonal influenza in the limited studies that have been done in that area,” says Louie. “It may be that H1N1 does cause more aggressive viral pneumonia, and some pathologic studies suggest this [H1N1] virus does have an affinity for receptors in the lower lung, but nobody really knows.”
“Obesity has doubled in adults and tripled in children over the past couple of decades,” Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, said in response to the study during a briefing with reporters. “We still need to understand what the consequences of that are. Increased susceptibility to infection is one. Reduced respiratory reserve is another. But it’s something we still need to learn more about.”
For now, Louie urges continued vigilance as flu season wears on. “This is not in my mind a disease to be taken lightly at all,” she says. “Especially if you have risk factors.”
See pictures of thermal scanners hunting for swine flu.
See pictures of the swine flu outbreak in Mexico.
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Older people most likely to die of swine flu: study
출처 : AFP Tue Nov 3, 6:59 pm ET
WASHINGTON (AFP) – People over the age of 50 who are hospitalized with swine flu are the group most likely to die from the illness, but (A)H1N1 flu remains a young person’s illness, US researchers said Tuesday.
Around 11 percent of the 1,088 cases of swine flu reported in California between April 17 and August 22 died, and although infants were most likely to be hospitalized with (A)H1N1 influenza, the death rate was higher among older people, researchers at the California department of health said.
“Overall fatality was 11 percent (118/1,088) and was highest (18-20 percent) in persons aged 50 years or older,” the researchers wrote in the study, which will appear in Wednesday’s issue of the Journal of the American Medical Association.
The death rate among children younger than 18 years, who made up around a third of swine flu cases reported in California in the first 16 weeks of the outbreak, was seven percent, the study said.
US health officials have repeatedly characterized swine flu as “a younger person’s disease” and put children and young adults under the age of 25 on a list of priority groups for vaccination against the disease.
More than half of hospitalizations and nearly a quarter of deaths in the United States from pandemic H1N1 have involved people under the age of 25.
“In contrast with the common perception that pandemic 2009 influenza A(H1N1) infection causes only mild disease, hospitalization and death occurred at all ages, and up to 30 percent of hospitalized cases were severely ill,” the Californian researchers said.
The study showed that the median time from onset of symptoms to death was 12 days and the most common causes of death were viral pneumonia and acute respiratory distress syndrome.
More than two-thirds of the California patients who were hospitalized with H1N1 had underlying medical conditions that have been previously associated with complications in flu cases, and some new conditions, such as obesity and high blood pressure.
“Most hospitalized cases had identifiable established risk factors; obesity may be a newly identified risk factor for fatal pandemic 2009 influenza A(H1N1) infection and merits further study,” the researchers wrote.
The United States is battling swine flu amid shortages of vaccine, which has seen states and counties cancel inoculation clinics, and of children’s anti-viral medicine, which last week saw federal authorities raiding the strategic stockpile for kids’ liquid Tamiflu.
Pandemic H1N1 flu has already claimed the lives of more children than seasonal flu typically does during an entire flu season, which runs from August until May.
More than 5,700 people have died worldwide since the virus was first discovered in April, with most of the deaths — 4,175 — in the Americas region, the World Health Organization said Friday.
