Lessons Learned from the 2009 H1N1 Virus Pandemic

A comprehensive study has revealed, for the first time, the impact of swine flu on the health of the general public in Australia and New Zealand.

The lessons learned in intensive care units (ICUs) across the two countries on the impact of the H1N1 (swine flu) virus are being shared with countries in the Northern Hemisphere to help them prepare for their upcoming flu season.

The three-month study, conducted at the height of the pandemic between June and August, reveals that 722 patients were admitted to ICUs and that at the peak of the epidemic up to 20 percent of ICU beds were occupied by patients with swine flu infection.

The study was co-coordinated by the Monash University-based Australian and New Zealand Intensive Care Research Centre (ANZIC-RC). The study involved all ICUs in Australia and New Zealand with the affected patients being treated in 109 of these units. The study was conducted utilizing the resources of the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG).

Dr. Ian Seppelt, a specialist in Intensive Care Medicine and based at Sydney's Nepean Hospital, said the impact of the virus on ICUs across Australia and New Zealand was dramatic.

"ICUs specialize in the management of patients with life-threatening illness and the surge of patients with H1N1 placed substantial strain on staff and resources. The most severely affected patients had pneumonia affecting both lungs that was caused by the virus. The number of patients admitted to ICUs with this complication represented a 600 per cent increase compared to previous years," Seppelt said.

Clinical associate professor Steve Webb, from the Intensive Care Unit at Royal Perth Hospital, was another key researcher on the project and said the information, which surfaced from the study will benefit other countries about to head into their winter flu season.

"Unlike previous 'seasonal' influenza strains, which impact heavily on elderly people and people with severe coexisting medical conditions, the H1N1 virus affected a different profile. Critical illness due to swine flu was most common in infants and middle aged people; with pregnant patients, the overweight, and indigenous patients particularly affected. Overall, about one-third of patients admitted to an ICU because of swine flu had no underlying health problems,” Webb said.

Professor Rinaldo Bellomo, foundation chair of the ANZICS CTG and director of intensive care research at Austin Health, Melbourne said the results of the study would be shared with health authorities in other countries to assist them better prepare for their flu season.

"We have come through our flu season and our assessment of the impact of the H1N1 strain will assist them prepare for any outbreak. The H1N1 virus has taken hold in many countries already, but many countries in the Northern Hemisphere will benefit from the lessons we have learned," Bellomo said. "Fortunately a vaccine is now available to prevent the complications of swine flu and it is important that all members of the community and especially those with risk factors, consider being vaccinated.”