Severe respiratory disease concurrent with the circulation of H1N1 influenza

Gerardo Chowell, Stefano M. Bertozzi, M. Arantxa Colchero, Hugo Lopez-Gatell, Celia Alpuche-Aranda, Mauricio Hernandez, Mark A. Miller

Research output: Contribution to journalArticle

537 Citations (Scopus)

Abstract

BACKGROUND: In the spring of 2009, an outbreak of severe pneumonia was reported in conjunction with the concurrent isolation of a novel swine-origin influenza A (H1N1) virus (S-OIV), widely known as swine flu, in Mexico. Influenza A (H1N1) subtype viruses have rarely predominated since the 1957 pandemic. The analysis of epidemic pneumonia in the absence of routine diagnostic tests can provide information about risk factors for severe disease from this virus and prospects for its control. METHODS: From March 24 to April 29, 2009, a total of 2155 cases of severe pneumonia, involving 821 hospitalizations and 100 deaths, were reported to the Mexican Ministry of Health. During this period, of the 8817 nasopharyngeal specimens that were submitted to the National Epidemiological Reference Laboratory, 2582 were positive for S-OIV. We compared the age distribution of patients who were reported to have severe pneumonia with that during recent influenza epidemics to document an age shift in rates of death and illness. RESULTS: During the study period, 87% of deaths and 71% of cases of severe pneumonia involved patients between the ages of 5 and 59 years, as compared with average rates of 17% and 32%, respectively, in that age group during the referent periods. Features of this epidemic were similar to those of past influenza pandemics in that circulation of the new influenza virus was associated with an off-season wave of disease affecting a younger population. CONCLUSIONS: During the early phase of this influenza pandemic, there was a sudden increase in the rate of severe pneumonia and a shift in the age distribution of patients with such illness, which was reminiscent of past pandemics and suggested relative protection for persons who were exposed to H1N1 strains during childhood before the 1957 pandemic. If resources or vaccine supplies are limited, these findings suggest a rationale for focusing prevention efforts on younger populations.

Original languageEnglish (US)
Pages (from-to)674-679
Number of pages6
JournalNew England Journal of Medicine
Volume361
Issue number7
DOIs
StatePublished - Aug 13 2009

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Human Influenza
Pandemics
Pneumonia
H1N1 Subtype Influenza A Virus
Age Distribution
Virus Diseases
Mexico
Orthomyxoviridae
Routine Diagnostic Tests
Population
Disease Outbreaks
Hospitalization
Swine
Vaccines
Age Groups
Mortality
Health

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Chowell, G., Bertozzi, S. M., Colchero, M. A., Lopez-Gatell, H., Alpuche-Aranda, C., Hernandez, M., & Miller, M. A. (2009). Severe respiratory disease concurrent with the circulation of H1N1 influenza. New England Journal of Medicine, 361(7), 674-679. https://doi.org/10.1056/NEJMoa0904023

Severe respiratory disease concurrent with the circulation of H1N1 influenza. / Chowell, Gerardo; Bertozzi, Stefano M.; Colchero, M. Arantxa; Lopez-Gatell, Hugo; Alpuche-Aranda, Celia; Hernandez, Mauricio; Miller, Mark A.

In: New England Journal of Medicine, Vol. 361, No. 7, 13.08.2009, p. 674-679.

Research output: Contribution to journalArticle

Chowell, G, Bertozzi, SM, Colchero, MA, Lopez-Gatell, H, Alpuche-Aranda, C, Hernandez, M & Miller, MA 2009, 'Severe respiratory disease concurrent with the circulation of H1N1 influenza', New England Journal of Medicine, vol. 361, no. 7, pp. 674-679. https://doi.org/10.1056/NEJMoa0904023
Chowell G, Bertozzi SM, Colchero MA, Lopez-Gatell H, Alpuche-Aranda C, Hernandez M et al. Severe respiratory disease concurrent with the circulation of H1N1 influenza. New England Journal of Medicine. 2009 Aug 13;361(7):674-679. https://doi.org/10.1056/NEJMoa0904023
Chowell, Gerardo ; Bertozzi, Stefano M. ; Colchero, M. Arantxa ; Lopez-Gatell, Hugo ; Alpuche-Aranda, Celia ; Hernandez, Mauricio ; Miller, Mark A. / Severe respiratory disease concurrent with the circulation of H1N1 influenza. In: New England Journal of Medicine. 2009 ; Vol. 361, No. 7. pp. 674-679.
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abstract = "BACKGROUND: In the spring of 2009, an outbreak of severe pneumonia was reported in conjunction with the concurrent isolation of a novel swine-origin influenza A (H1N1) virus (S-OIV), widely known as swine flu, in Mexico. Influenza A (H1N1) subtype viruses have rarely predominated since the 1957 pandemic. The analysis of epidemic pneumonia in the absence of routine diagnostic tests can provide information about risk factors for severe disease from this virus and prospects for its control. METHODS: From March 24 to April 29, 2009, a total of 2155 cases of severe pneumonia, involving 821 hospitalizations and 100 deaths, were reported to the Mexican Ministry of Health. During this period, of the 8817 nasopharyngeal specimens that were submitted to the National Epidemiological Reference Laboratory, 2582 were positive for S-OIV. We compared the age distribution of patients who were reported to have severe pneumonia with that during recent influenza epidemics to document an age shift in rates of death and illness. RESULTS: During the study period, 87{\%} of deaths and 71{\%} of cases of severe pneumonia involved patients between the ages of 5 and 59 years, as compared with average rates of 17{\%} and 32{\%}, respectively, in that age group during the referent periods. Features of this epidemic were similar to those of past influenza pandemics in that circulation of the new influenza virus was associated with an off-season wave of disease affecting a younger population. CONCLUSIONS: During the early phase of this influenza pandemic, there was a sudden increase in the rate of severe pneumonia and a shift in the age distribution of patients with such illness, which was reminiscent of past pandemics and suggested relative protection for persons who were exposed to H1N1 strains during childhood before the 1957 pandemic. If resources or vaccine supplies are limited, these findings suggest a rationale for focusing prevention efforts on younger populations.",
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AU - Alpuche-Aranda, Celia

AU - Hernandez, Mauricio

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N2 - BACKGROUND: In the spring of 2009, an outbreak of severe pneumonia was reported in conjunction with the concurrent isolation of a novel swine-origin influenza A (H1N1) virus (S-OIV), widely known as swine flu, in Mexico. Influenza A (H1N1) subtype viruses have rarely predominated since the 1957 pandemic. The analysis of epidemic pneumonia in the absence of routine diagnostic tests can provide information about risk factors for severe disease from this virus and prospects for its control. METHODS: From March 24 to April 29, 2009, a total of 2155 cases of severe pneumonia, involving 821 hospitalizations and 100 deaths, were reported to the Mexican Ministry of Health. During this period, of the 8817 nasopharyngeal specimens that were submitted to the National Epidemiological Reference Laboratory, 2582 were positive for S-OIV. We compared the age distribution of patients who were reported to have severe pneumonia with that during recent influenza epidemics to document an age shift in rates of death and illness. RESULTS: During the study period, 87% of deaths and 71% of cases of severe pneumonia involved patients between the ages of 5 and 59 years, as compared with average rates of 17% and 32%, respectively, in that age group during the referent periods. Features of this epidemic were similar to those of past influenza pandemics in that circulation of the new influenza virus was associated with an off-season wave of disease affecting a younger population. CONCLUSIONS: During the early phase of this influenza pandemic, there was a sudden increase in the rate of severe pneumonia and a shift in the age distribution of patients with such illness, which was reminiscent of past pandemics and suggested relative protection for persons who were exposed to H1N1 strains during childhood before the 1957 pandemic. If resources or vaccine supplies are limited, these findings suggest a rationale for focusing prevention efforts on younger populations.

AB - BACKGROUND: In the spring of 2009, an outbreak of severe pneumonia was reported in conjunction with the concurrent isolation of a novel swine-origin influenza A (H1N1) virus (S-OIV), widely known as swine flu, in Mexico. Influenza A (H1N1) subtype viruses have rarely predominated since the 1957 pandemic. The analysis of epidemic pneumonia in the absence of routine diagnostic tests can provide information about risk factors for severe disease from this virus and prospects for its control. METHODS: From March 24 to April 29, 2009, a total of 2155 cases of severe pneumonia, involving 821 hospitalizations and 100 deaths, were reported to the Mexican Ministry of Health. During this period, of the 8817 nasopharyngeal specimens that were submitted to the National Epidemiological Reference Laboratory, 2582 were positive for S-OIV. We compared the age distribution of patients who were reported to have severe pneumonia with that during recent influenza epidemics to document an age shift in rates of death and illness. RESULTS: During the study period, 87% of deaths and 71% of cases of severe pneumonia involved patients between the ages of 5 and 59 years, as compared with average rates of 17% and 32%, respectively, in that age group during the referent periods. Features of this epidemic were similar to those of past influenza pandemics in that circulation of the new influenza virus was associated with an off-season wave of disease affecting a younger population. CONCLUSIONS: During the early phase of this influenza pandemic, there was a sudden increase in the rate of severe pneumonia and a shift in the age distribution of patients with such illness, which was reminiscent of past pandemics and suggested relative protection for persons who were exposed to H1N1 strains during childhood before the 1957 pandemic. If resources or vaccine supplies are limited, these findings suggest a rationale for focusing prevention efforts on younger populations.

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