Most strains of influenza are successfully fought off by the vast majority of people, who are back to normal within a week or two. Nevertheless, flu can cause serious illness, and sometimes death, in the elderly and other vulnerable people. A flu outbreak also puts a considerable strain on hospitals, as the number of people admitted always increases during an outbreak, not just for respiratory problems but for a variety of other medical conditions.
In cooler ('temperate') countries, all this has been known–backed up by a number of statistical studies–for many years. However, it has been assumed that flu is only a minor problem for people in the warmer parts of the world – the tropics and subtropics. Most countries in these regions are developing nations, and collecting and analysing data on flu and its complications is not easy. Flu outbreaks also happen at unpredictable and irregular intervals, in contrast to the seasonal pattern seen in temperate countries, and this creates problems for the statisticians.
Researchers in Hong Kong (which is in the subtropics) realised that they were well placed to study the impact of flu in such a location. Hong Kong has a sophisticated health care system, which includes advanced computerised record keeping. Ninety-five per cent of people admitted to hospital are treated in public hospitals and their records were available to the researchers. They developed new statistical methods to allow for the irregular nature of Hong Kong's flu outbreaks.
The researchers found that, during outbreaks, hospital admissions increased, not just for respiratory diseases such as pneumonia but also for heart conditions, stroke and diabetes. The increases were most noticeable for older people. Overall, influenza was responsible for 11.6% of admissions for respiratory disease, 1.5% of admissions for stroke, 1.8% of admissions for heart attacks, and 3.5% of admissions for diabetes. These figures are comparable with what has been found in temperate countries, for example the USA. It has also been noted, however, that more children are admitted to Hong Kong's hospitals during flu outbreaks than happens in the US.
Hong Kong is a wealthy subtropical city and it is different in many respects from low-income countries in the tropics, which face massive problems with other diseases and lack the modern health care that is available in Hong Kong. Nevertheless, the results of this study suggest that influenza deserves to be given a higher priority than it has at present in the tropics and subtropics. The authors urge the introduction of vaccination programs for people at high risk, particularly the elderly.
PLEASE MENTION THE OPEN-ACCESS JOURNAL PLoS MEDICINE (www.plosmedicine.org) AS THE SOURCE FOR THESE ARTICLES AND PROVIDE A LINK TO THE FREELY-AVAILABLE TEXT. THANK YOU.
All works published in PLoS Medicine are open access. Everything is immediately available without cost to anyone, anywhere--to read, download, redistribute, include in databases, and otherwise use--subject only to the condition that the original authorship is properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
Citation: Wong CM, Yang L, Chan KP, Leung G, Chan KH, et al. (2006) Influenza-associated hospitalization in a subtropical city. PLoS Med 3(4): e121.
PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE
VERSIONS OF YOUR REPORT: http://dx.doi.org/10.1371/journal.pmed.0030121
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-03-04-peiris.pdf
PRESS-ONLY PREVIEW OF THE SYNOPSIS: http://www.plos.org/press/plme-03-04-peiris-syn.pdf
CONTACT:
Joseph S. M Peiris
The University of Hong Kong
Department of Microbiology
Queen Mary Hospital
Pokfulam Rd
Hong Kong, SAR
China
Tel: (852)-2855-4888
Fax: (852)-2855-1241
malik@hkucc.hku.hk
About PLoS Medicine
PLoS Medicine is an open access, freely available international medical journal. It publishes original research that enhances our understanding of human health and disease, together with commentary and analysis of important global health issues. For more information, visit http://www.plosmedicine.org
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org
Journal
PLoS Medicine