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Perspective

Influenza A (H1N1) Virus, 2009 — Online Monitoring

John S. Brownstein, Ph.D., Clark C. Freifeld, B.S., and Lawrence C. Madoff, M.D.

N Engl J Med 2009; 360:2156May 21, 2009

Article

The value of Web-based information for early disease detection, public health monitoring, and risk communication has never been as evident as it is today, given the emergence of the current influenza A (H1N1) virus. Many ongoing efforts have underscored the important roles that Internet and social-media tools are playing in the detection of and response to this outbreak.

In March and early April, while much of the world was focusing on the threat of avian influenza originating in Asia, intelligence-gathering systems were also extracting evidence of an epidemic of acute respiratory infections in Mexico. Early informal reports from the Mexican press indicated that a “mysterious” influenza-like illness was occurring in the town of La Gloria in the state of Veracruz, where it was reported that up to 60% of the 3000 inhabitants had been infected and 2 had died since early March. The HealthMap system, for instance, collected and disseminated a local media report describing this event on April 1, 2009 (see mapInformation on Suspected or Confirmed Cases of H1N1 Influenza That HealthMap Has Collected since April 1 from Mexico, the Southern United States, and Central America.).1 This report was followed by another on April 2 describing the possible role of Granjas Carroll, a U.S.-owned pig farm, in the epidemic.2 On April 10, the Global Public Health Intelligence Network (GPHIN) reported acute respiratory illness in Veracruz to the World Health Organization (WHO). This alert was followed by immediate communication among the WHO's Global Outbreak Alert and Response Network, the Pan American Health Organization, and the Mexican Ministry of Health.3

Other informal media sources subsequently began to reflect the spread of the epidemic through parts of Mexico, including Oaxaca, Baja California, Mexico City, and San Luis Potosí. Reports of this outbreak did not appear in the English-language media until weeks later (April 21), when two children living near San Diego (neither of whom had been exposed to pigs) presented with mild respiratory symptoms and fever. In those cases, the Centers for Disease Control and Prevention had confirmed the presence of H1N1 on April 17.4 The timeline thus emphasizes the importance of surveillance of local information sources in local languages.

Epidemic-intelligence systems receive many reports of mysterious respiratory illness daily, and the decision to consider this event one of international significance requires interpretation of context — for example, of the level of background noise inherent in various data-mining systems. A fully moderated approach (in which each communication is reviewed by someone with expertise in the subject matter), such as that of the International Society for Infectious Diseases' Program for Monitoring Emerging Diseases (ProMED), though potentially less timely, provides critical, evidence-based risk assessment. An in-depth evaluation is required to determine whether any earlier intervention efforts might have controlled the outbreak at the source. Clearly, this event also highlights the swift response capability of the global public health community.

The emergence of H1N1 has been subsequently tracked through both automated and manual data entry and visualization with the use of full-spectrum Web-based communication strategies. Though traditional official and media communication channels remain in place, Web-based mapping, search-term surveillance, “microblogging,” and online social networks have emerged as alternative forms of rapid dissemination of information. Understandably, some observers worry about their ability to inspire public concern beyond the necessary levels. Clearly, these tools must be used with restraint and appropriate evaluation.

Dr. Brownstein, Mr. Freifeld, and Dr. Madoff report receiving grant support from Google.org. No other potential conflict of interest relevant to this article was reported.

This article (10.1056/NEJMp0904012) was published at NEJM.org on May 7, 2009.

Source Information

Dr. Brownstein is a faculty member at the Children's Hospital Informatics Program, Children's Hospital Boston, and an assistant professor of pediatrics at Harvard Medical School, Boston. Mr. Freifeld is a research software developer at the Children's Hospital Informatics Program in Boston and a master's candidate in the New Media Medicine Group of the MIT Media Laboratory in Cambridge, MA. Dr. Brownstein and Mr. Freifeld are the cocreators of the HealthMap system. Dr. Madoff is a professor of medicine at the University of Massachusetts Medical School, Worcester, an infectious disease physician with the Massachusetts Department of Public Health, Boston, and editor of ProMED-mail, a program of the International Society for Infectious Diseases.

References

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    Swine influenza A (H1N1) infection in two children -- southern California, March-April 2009. MMWR Morb Mortal Wkly Rep 2009;58:400-402
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Citing Articles (11)

Citing Articles

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    Rachel D. Schwartz, Brett R. Bayles. (2011) US university response to H1N1: A study of access to online preparedness and response information. American Journal of Infection Control
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    Shawndra Hill, Jun Mao, Lyle Ungar, Sean Hennessy, Charles E Leonard, John Holmes. (2011) Natural Supplements for H1N1 Influenza: Retrospective Observational Infodemiology Study of Information and Search Activity on the Internet. Journal of Medical Internet Research 13:2,
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    Susan Koch-Weser, Ylisabyth S. Bradshaw, Lisa Gualtieri, Susan S. Gallagher. (2010) The Internet as a Health Information Source: Findings from the 2007 Health Information National Trends Survey and Implications for Health Communication. Journal of Health Communication 15:sup3, 279-293
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    Anne Gatewood Hoen, David L. Buckeridge, Emily H. Chan, Clark C. Freifeld, Mikaela Keller, Katia Charland, Christl A. Donnelly, John S. Brownstein. (2010) Characteristics of US public schools with reported cases of novel influenza A (H1N1). International Journal of Infectious Diseases 14, e6-e8
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    Joseph B. McCormick, Chris Yan, Jessica Ballou, Yvette Salinas, Belinda Reininger, Jennifer Gay, Fidel Calvillo, J. Gaines Wilson, Leonel Lopez, Susan P. Fisher-Hoch. (2010) Response to H1N1 in a U.S.-Mexico Border Community. Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science 8:3, 233-242
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    Yaowu Yang, Richard Gonzalez, Fang Huang, Wei Wang, Yongjun Li, Guy Vernet, Jianwei Wang, Qi Jin. (2010) Simultaneous typing and HA/NA subtyping of influenza A and B viruses including the pandemic influenza A/H1N1 2009 by multiplex real-time RT-PCR. Journal of Virological Methods 167:1, 37-44
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    Brownstein, John S., Freifeld, Clark C., Chan, Emily H., Keller, Mikaela, Sonricker, Amy L., Mekaru, Sumiko R., Buckeridge, David L., . (2010) Information Technology and Global Surveillance of Cases of 2009 H1N1 Influenza. New England Journal of Medicine 362:18, 1731-1735
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    J. Silva Marques, A. Veiga, J. Nobrega, M. J. Correia, J. de Sousa. (2010) Electrical storm induced by H1N1 A influenza infection. Europace 12:2, 294-295
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    Mary Virginia Taylor, Priscilla L. Stephenson. (2009) Influenza A (H1N1) Virus (Swine Influenza): A Webliography. Journal of Consumer Health On the Internet 13:4, 374-385
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    Dominic A. Fitzgerald. (2009) Human swine influenza A [H1N1]: Practical advice for clinicians early in the pandemic. Paediatric Respiratory Reviews 10:3, 154-158
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    Jina Lee, Hoan Jong Lee. (2009) Novel swine-origin H1N1 influenza. Korean Journal of Pediatrics 52:8, 862
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