Though it's difficult to tell whether H1N1 will become a global disaster, it's certain that emergency physicians will have to deal with it, and probably with a fair number of cases of panic disguised as swine flu.
When swine flu first arrived, no one imagined that it would garner the attention it did. “That first test was nothing unusual because we do get occasional swine viruses coming in,” said Michael W. Shaw, PhD, the associate director for laboratory science of the Centers for Disease Control and Prevention Influenza Division, who first clarified the timeline of the H1N1 outbreak. “What was unusual was that we started getting some sequence information, and it became clear that it wasn't anything that we'd ever seen before.”
Speaking at a recent symposium on novel influenza pandemics at the New York Academy of Sciences, Dr. Shaw explained how a sample from a patient exhibiting no alarming symptoms could not be subtyped in a clinical trial at the Naval Health Research Center in San Diego. Two weeks later, on April 15, the specimens arrived at the CDC, and were confirmed to be swine H1.
The same strain was found in a second California case April 17, and in the days that followed, the United States reported the cases to the World Health Organization. The CDC then issued a Morbidity and Mortality Weekly Report on swine flu, and by April 23, genetic tests confirmed Mexican and U.S. samples were positive for H1N1.
By the end of May, U.S. H1N1 cases numbered near 8000, and all but two states had been affected. Texas (1358 cases), Wisconsin (1130), and Illinois (927) were heavily affected, with more than 500 cases each in Arizona, California, and Washington, although only a dozen deaths across the nation had been reported.
Based on the incoming data, the CDC offered some preliminary clinical insights, most notably that the vast majority of cases (87%) were in patients under 65, with 60 percent in the 5–24 age group. “These groups are the ones that have no preexisting immunity,” Dr. Shaw said, because individuals born before 1957 were likely exposed to H1 previously.
Though H1N1 is currently grabbing headlines, Dr. Shaw cautioned there is still H3, some seasonal H1, and type B out there. “H3 circulating has us concerned because it's confusing the picture for clinicians. If you know what strain you've got, you know what drug to give to the patient,” he said.
Symptom nuances may help EPs differentiate between seasonal and swine flu. Dr. Shaw said most H1N1 patients exhibited fever as expected, but five percent did not, and those patients were older. Older patients also were more likely to present with cough and shortness of breath, with vomiting seen more in younger patients. He added that a relatively high number of patients reported diarrhea. Having a family member with the illness posed the biggest risk, Dr. Shaw said, although travel to Mexico diminished as a risk factor and will likely fall off the chart eventually.
Global spread is now the primary concern, and the CDC sent free assay kits to 140 countries. H1N1 is “just starting to show up in the Southern Hemisphere,” Dr. Shaw said. “As it spreads to more countries, we're going to see more variation. There's a possibility of reassortment. There's a possibility of it picking up antiviral resistance. Stay tuned.”
Local H1N1 Response
As H1N1 moves internationally, experts will look to “the experience at the local level, where the boots are on the ground,” said Scott Harper, MD, MPH, a medical epidemiologist at the New York City Department of Health and Mental Hygiene.
New York serves as a good example because it boasts a robust public health organization, which has had a pandemic influenza plan in place for three years. It also was the site of an early H1N1 outbreak among students at St. Francis Preparatory School.
Under the DOH's standard surveillance efforts, 95 percent of all ED visits are classified by syndrome, including a “flu-like” category, enabling identification of disease clusters in the community. The worried well may flood EDs in times of panic, however, skewing data and overwhelming staff, Dr. Harper said. In an informal survey, he found “for every 100 people showing up to the emergency department right now complaining of influenza-like illness, only one or [fewer is] being admitted.”
Frequent dialogue with the medical community is a big focus of the DOH effort, and it's a two-way street. The DOH provides frequent health alerts by email or fax updating providers on the local flu situation as well as a Provider Access Line, where health care professionals can seek testing supplies, treatment recommendations, or a second opinion. The department in turn requests feedback via conference calls or surveys regarding capacity, needs, and antiviral supplies.
Many questions persist, Dr. Harper said. Is this a pandemic, will this be a pandemic, and how do you define pandemic? What's optimal antiviral use — treatment or prophylaxis? What's most effective at the clinical level, at the population level? Is there a vaccine being developed? Who should get it, and how will vaccines be delivered? Who's going to pay for all this? With no shortage of questions to keep scientists busy, they hope new data will guide best practices.
Vaccines and More Vaccines
Other presentations at the New York Academy of Sciences symposium discussed topics of some interest to emergency physicians.
▪ Kanta Subbarao, MD, PhD, a senior investigator at the National Institute of Allergy and Infectious Disease, spoke on vaccine development, not only for H1N1 but also for H5, H7, and H9 subtype avian viruses.
▪ John Treanor, MD, a professor of microbiology and immunology at the University of Rochester, reported on possibilities of using a monovalent supplemental vaccine; incorporating a novel H1 component into the trivalent, seasonal vaccine; and working with cell cultures as new substrates.
▪ Dominick Iacuzio, PhD, the medical director of Hoffmann-La Roche, Inc., a manufacturer of antiviral drugs, lectured about the use of oseltamivir against seasonal and avian influenza.
▪ Philip Dormitzer, MD, PhD, the senior director at Novartis Vaccines and Diagnostics, discussed recent work with vaccines adjuvanted with oil in water emulsions, such as MF59.
The common thread through the lectures was an urgent need for preparedness. As Edwin D. Kilbourne, MD, a professor emeritus of microbiology and immunology at New York Medical College, said in the keynote lecture: “We can't predict, but we must prepare.”
All the symposium presentations and a concluding panel discussion are available at the New York Academy of Sciences web site (http://www.nyas.org/ebrief/miniEB.asp?eBriefID=781).
ACEP Releases H1N1 Strategic Plan
The American College of Emergency Physicians recently released a plan to help emergency providers plan for the H1N1 surge expected as early as September. The National Strategic Plan for Emergency Department Management of Outbreaks of Novel H1N1 Influenza provides recommendations for EDs and first responders to manage swine flu cases, including appointing an officer for H1N1 preparedness, establishing connections between government and hospitals, and training all who may be involved.
“When H1N1 first hit the United States this spring, we saw big surges in patients, many of whom had been sent to us by their primary care physicians,” said Nicholas Jouriles, MD, the president of ACEP. “We know the ER is the place people turn to in a medical crisis, and we are dedicated to being prepared for the worst-case scenarios, even as we hope they will not occur.”
The plan was produced under contract to the Office of the Assistant Secretary for Preparedness and Response (ASPR) and the Emergency Care Coordination Center (ECCC). A collaboration of ASPR, ECCC, and ACEP, the strategy recommends ways to manage widespread influenza infection using threat awareness, protection and prevention, surveillance and detection, and response and recovery.
“While H1N1's virulence is not predictable, it is expected to be highly contagious, and will place added strains on the emergency care system,” said Dr. Jouriles. “Emergency medical and hospital planning for an H1N1 pandemic will be successful only if there is cooperation between first responders and public health officials.”
Read the plan here.