Reacting to the emergence of swine-origin influenza A H1N1
Authors: Catherine WM Ong, Khek Yu Ho, Li Yang Hsu, Aymeric YT Lim, Dale A Fisher, Paul A Tambyah
Journal: The Lancet Infectious Diseases (2009)

2009 saw a new swine-origin influenza A H1N1 virus emerge in Mexico, then the USA, and, in a matter of weeks, multiple countries in four continents.1WHOEpidemic and pandemic alert and response: situation updates—influenza A(H1N1).http://www.who.int/csr/disease/swineflu/updates/en/index.htmlGoogle Scholar The initial perception of high mortality among young Mexicans coupled with its rapid spread worldwide raised the spectre of the devastating severe acute respiratory syndrome (SARS) epidemic of 2003. WHO raised its pandemic alert level from three to five—signifying an imminent pandemic—within 3 days.1WHOEpidemic and pandemic alert and response: situation updates—influenza A(H1N1).http://www.who.int/csr/disease/swineflu/updates/en/index.htmlGoogle Scholar, 2WHOStatement by WHO Director-General, Dr Margaret Chan: influenza A(H1N1).http://www.who.int/mediacentre/news/statements/2009/h1n1_20090429/en/index.htmlGoogle Scholar The US Centers for Disease Control and Prevention rapidly characterised the virus, providing information on its antiviral susceptibility, molecular biology, and epidemiology online3Centers for Disease Control and PreventionInterim guidance for clinicians on identifying and caring for patients with swine-origin influenza A (H1N1) virus infection.http://www.cdc.gov/h1n1flu/identifyingpatients.htmGoogle Scholar, 4Centers for Disease Control and PreventionNovel H1N1 influenza: resources for clinicians.http://www.cdc.gov/h1n1flu/clinicians/Google Scholar and through international teleconferences organised by WHO. Countries rushed to control the epidemic. Some of the most drastic actions were taken by China and Hong Kong. The former quarantined Canadian and Mexican nationals, while the latter sealed off an entire hotel when the first case of H1N1 influenza was detected in a Mexican guest, placing all other guests and staff under quarantine.5BBC NewsChina denies flu discrimination.http://news.bbc.co.uk/2/hi/asia-pacific/8032157.stmGoogle Scholar Singapore, which has no confirmed cases so far, activated its pandemic plan immediately after WHO raised their alert level from three to four. The Disease Outbreak Response System (DORSCON)-FLU framework—a series of colour-coded alert levels—was designed for a stepwise national pandemic response.6Ministry of Health, SingaporeDetails of the influenza pandemic plan.http://www.moh.gov.sg/mohcorp/currentissues.aspx?id=20764Google Scholar A yellow alert was declared on April 28, 2009, one day after WHO raised the pandemic threat to level four. Installation of thermal scanners at the borders to detect febrile travellers entering the country was implemented, with a dedicated ambulance service to send suspected cases to the designated hospital. Health-care workers at all emergency departments, isolation wards, and intensive care units were required to wear full personal-protective equipment including N95 masks, gloves, and gowns. Each inpatient was restricted to two visitors, who had their details recorded to help with contact tracing. When WHO raised the pandemic alert level to five an orange alert was declared. All health-care workers were required to wear N95 masks at work and had their temperatures monitored twice-daily. Office staff in health-care facilities wore surgical masks. Medical and nursing student clinical postings were cancelled. Each patient could only have one visitor per day, and checkpoints were established at all hospital entrances. Movement of patients and health-care workers between hospitals was restricted, and rotations of junior doctors suspended. Medical conferences were cancelled, leave for health-care workers was curtailed, and elective surgical procedures were postponed. Hospitals restricted overseas travel for their employees, mandating quarantine or virological screening on return from countries that had reported local transmission. Additionally, travellers who had returned from Mexico were quarantined for 7 days. Schools were required to begin temperature monitoring of all students. Public health messages went out on social distancing, hand hygiene, and social responsibility. These measures were only de-escalated to DORSCON yellow on May 7, when it became apparent that the disease was not as virulent as predicted. Visitor restrictions with staff temperature surveillance and enhanced infection control in hospitals continued. The drastic measures taken in Singapore, Hong Kong, and China might seem excessive compared with other responses that focused on heightened influenza surveillance, enhanced infection control, limited travel restrictions, and school closures. However, it is important to bear in mind that Singapore, Hong Kong, and China were among the worst hit by the SARS epidemic. The deaths of many dedicated health-care workers during SARS,7Hsu LY Lee CC Green JA et al.Severe acute respiratory syndrome (SARS) in Singapore: clinical features of index patient and initial contacts.Emerg Infect Dis. 2003; 9: 713-717Crossref PubMed Scopus (263) Google Scholar and the economic devastation wrought by the outbreak,8Yazdanpanah Y Daval A Alfandari S et al.Analysis of costs attributable to an outbreak of severe acute respiratory syndrome at a French hospital.Infect Control Hosp Epidemiol. 2006; 27: 1282-1285Crossref PubMed Scopus (3) Google Scholar, 9Gupta AG Moyer CA Stern DT The economic impact of quarantine: SARS in Toronto as a case study.J Infect. 2005; 50: 386-393Summary Full Text Full Text PDF PubMed Scopus (65) Google Scholar, 10Liu JT Hammitt JK Wang JD Tsou MW Valuation of the risk of SARS in Taiwan.Health Econ. 2005; 14: 83-91Crossref PubMed Scopus (65) Google Scholar have clearly influenced policy makers in their decision to rapidly implement draconian measures. Influenza A H1N1 is virologically and epidemiologically a different virus from SARS. Although a nurse in Germany is reported to have acquired the virus nosocomially, the overwhelming majority of infections were community-acquired. Isolation of patients has been associated with adverse outcomes11Stelfox HT Bates DW Redelmeier DA Safety of patients isolated for infection control.JAMA. 2003; 290: 1899-1905Crossref PubMed Scopus (479) Google Scholar as has the prolonged use of personal-protective equipment by health-care workers.12Foo CC Goon AT Leow YH Goh CL Adverse skin reactions to personal protective equipment against severe acute respiratory syndrome—a descriptive study in Singapore.Contact Dermatitis. 2006; 55: 291-294Crossref PubMed Scopus (227) Google Scholar, 13Lim EC Seet RC Lee KH Wilder-Smith EP Chuah BY Ong BK Headaches and the N95 face-mask amongst healthcare providers.Acta Neurol Scand. 2006; 113: 199-202Crossref PubMed Scopus (201) Google Scholar The unintended consequences of resource diversion on the rest of the health-care system during SARS have been reported.14Centers for Disease Control and PreventionEfficiency of quarantine during an epidemic of severe acute respiratory syndrome—Beijing, China, 2003.MMWR Morb Mortal Wkly Rep. 2003; 52: 1037-1040PubMed Google Scholar It remains to be seen if the draconian measures taken by previously SARS-affected countries will be cost-effective in the control of pandemic influenza. There is a crucial need for well designed prospective quasiexperimental studies to evaluate these responses. These studies will form the evidence base in preparation for a pandemic of emerging infections with different degrees of virulence. PAT has received research support from Baxter, Adamas, and Merlion Pharmaceuticals. He has also received speaker fees and honoraria from Novartis, Pfizer, Wyeth, the Asia Pacific Advisory Council on Influenza, the Asian Hygiene Council and IBC Asia. The other authors declare no conflicts of interest.