New research shows that individuals with mild H1N1 infection may go undetected using standard diagnostic criteria, according to a study in the August issue of the American Journal of Infection Control, the official publication of the Association for Professionals in Infection Control and Epidemiology, (APIC). The study concludes that coughing or other respiratory symptoms are more accurate in determining influenza infection than presence of a fever.

Currently, public health officials rely on body temperature (detecting fever) to screen individuals for potential infection with H1N1. For example, during a pandemic, standard screening at airports relies on body temperature scanners to detect the presence of fever. However, the study's authors found that coughing, not fever, is a more reliable indicator of infection because nearly half of the individuals with mild infection may not have fever.

A team led by Sang Won Park, MD, professor at the Seoul National University, investigated confirmed cases of H1N1 who were hospitalized and quarantined during the early stages of the pandemic in 2009. The study's results showed only 45.5 percent of the case subjects had fever. Individuals with mild infection and no fever have the potential to evade detection at airports or medical triage units, thus continuing the chain of infection.

"Our study found that fever is not reliable for case definition, even though it has been regarded as a key factor in determining influenza infection," said Dr. Park. "We are aware of other studies that show fever present in as few as 31 percent of confirmed cases of influenza. We found that the most sensitive indicator was cough."

Dr. Park adds that that "screening should take any kind of respiratory manifestation into account."

About AJIC: American Journal Of Infection Control

AJIC: American Journal of Infection Control covers key topics and issues in infection control and epidemiology. Infection preventionists, including physicians, nurses, and epidemiologists, rely on AJIC for peer-reviewed articles covering clinical topics as well as original research. As the official publication of the Association for Professionals in Infection Control and Epidemiology, Inc. (APIC), AJIC is the foremost resource on infection control, epidemiology, infectious diseases, quality management, occupational health, and disease prevention. AJIC also publishes infection control guidelines from APIC and the CDC. Published by Elsevier, AJIC is included in MEDLINE and CINAHL.

Notes

"Mild form of 2009 H1N1 influenza infection detected by active surveillance: Implications for infection Control" appears in the American Journal of Infection Control, Volume 38, Issue 6 (August 2010) published by Elsevier.

Authors:

Ina Jeong, MD, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute, Seoul National University

Chang-hoon Lee, MD, Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Republic of Korea.

Deog Kyeom Kim, MD, Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Republic of Korea.

Hee Soon Chung, MD, Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Republic of Korea.

Sang Won Park, MD, Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Republic of Korea.

Source:
APIC