Australian Report Critiques Lack of Communication During Freak Thunderstorm Asthma Outbreak

An increase in asthma attacks in November could be linked to the weather.

Australian emergency management officials suspected that a spike in asthma attacks last November might have been weather related, but a recent report suggested they did little to communicate their theory.

The account, from the State of Victoria’s inspector general for emergency management (IGEM) Tony Pearce, detailed the state’s response when a rash of storms sent more than 8,500 people to the hospital with asthma attacks last November, leaving nine people dead. It provided a blueprint for how healthcare workers and emergency managers worldwide should respond to the rare, but serious event.

Thunderstorm asthma is a little-understood phenomenon, apparently caused by the combination of “extremely high” levels of grass pollen and thunderstorm conditions.

“These drafts concentrate particles of pollens and mold spores and then sweep them into the high humidity of the clouds,” wrote Annie Arrey-Mensah, MD, of the Michigan-based Asthma Allergy and Immunology Institute, in an institute newsletter. “They are broken down into small, respirable fragments, which are released by rain. Because these allergens are high concentrated, they can cause severe asthma attacks in patients who are sensitized to the various allergens.”

The storm — actually a collection of several small thunderstorm cells – swept into Melbourne and the surrounding area near rush hour on the evening of Nov. 21. As the storms came through, emergency managers sent out a severe thunderstorm warning, but otherwise saw nothing unusual, according Pearce.

However, by 7 p.m., calls for ambulances started to spike, with nearly 200 respiratory distress-related arrivals at Melbourne emergency departments. By midnight, hospitals were receiving more than 300 patients per hour with respiratory problems.

Pearce said the state’s ambulance and emergency communications services didn’t formally enact their highest emergency statuses, but did take actions that were aligned with high-level emergencies. Still, he said, emergency managers might have been in more trouble had the situation not slowed down by the following morning.

“IGEM considers that had the thunderstorm asthma event been protracted, the demand on pre-hospital and hospital response would have become increasingly difficult to sustain,” he wrote. “In this regard, a conservative and early escalation of response levels based on available triggers and information should be considered.”

In the Australian outbreak, Pearce said the state’s emergency services didn’t do a good enough job of spreading critical information widely and quickly.

“The normal out-of-hours communications processes for the management of routine business were inadequate for managing an effective response to a large scale thunderstorm asthma event,” he said. “Communications were linear, between two parties only, or email based, rather than group meetings and/or conference calls.”

Pearce said there was early speculation by some that the asthma outbreak might be storm-related, but it didn’t reach a broad audience. “As a result… there was limited capacity to rapidly piece together and share a common operating picture of the developing situation,” he said.

Despite his critique, Pearce said it is important to place the event in historical context.

“The number of people affected and the severity of the consequences suggest this thunderstorm asthma event was without international precedent,” Pearce wrote. “...Of the globally-documented episodes of epidemic thunderstorm asthma, fatalities appear rare.”

The Pearce report is available in full online. A final report is expected to publish in April.

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