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2004VaccineRegistry

Vaccine Associated Myopericarditis Registry (2004)

The United States Department of Defense (DoD) smallpox vaccination program was launched on December 13, 2002 for emergency responders as part of homeland defense and for military personnel engaged in the war on terrorism.  The Walter Reed Army Medical Center’s Department of Allergy & Immunology and Vaccine Healthcare Centers Network (VHC, http://www.vhcinfo.org/ External link (opens new browser window), https://askvhc.wramc.amedd.army.mil/ External link (opens new browser window)) and the Military Vaccine Agency (MILVAX, http://www.vaccines.mil External link (opens new browser window)) of the U.S. Army Office of the Surgeon General and Army Medical Department developed and refined the clinical implementation policies for the program.  The first program based vaccinations since the declaration of smallpox as the first infectious disease eradicated worldwide in 1980 was performed at Walter Reed Army Medical Center in December of 2002.  The DoD has now immunized over 1.2 million service members and employees as part of the smallpox vaccination program.  A parallel civilian voluntary program has immunized approximately 40,000 first responders throughout the United States contributing to homeland preparedness.

Since the initiation of the DoD program, approximately 150 vaccinees have experienced cardiac complications following vaccination, including myopericarditis and ischemic events.  This prompted the establishment of a formal registry within the Walter Reed National Vaccine Healthcare Centers Network in 2004 to track patients experiencing this rare adverse event due to smallpox or other vaccinations.

Several reports have chronicled the initial presentation and acute management of myopericarditis patients in an attempt to identify risk factors and further adjust screening strategies to minimize the potential for this complication in those vaccinated.  The vast majority of those affected have been vaccinated for the first time (primary vaccinees) and are young adult Caucasian males.  Whether these characteristics are true risk factors or are a result of the population being vaccinated remains to be seen.  Several studies are underway to prospectively determine phenotypic and genotypic risk factors.

The initial reports also have alluded to the general favorable outcome of post-vaccination myopericarditis patients.  However, there have been no published reports of systematically acquired data to support the anecdotal clinical observation that patients experience complete resolution of their clinical symptoms and are essentially back to a baseline level of function within weeks to months of their acute symptoms.  Furthermore, it is unknown whether the cardiac and/or pericardial inflammatory process has put these patients at increased risk for either persistent or delayed onset cardiac sequelae such as cardiomyopathy or congestive heart failure.  Whereas most patients recover within weeks to a few months, some have residual constitutional symptoms that can persist for several months.  As of 30 June 2003, the Walter Reed National Vaccine Healthcare Center Network (comprising regional sites at Walter Reed, Portsmouth Naval Medical Center, Brooke Army Medical Center, and Wilford Hall) in collaboration with US Army cardiologists and the Military Vaccine Agency (MILVAX) have participated in the identification, management and follow-up of all cases.

Outcomes of the registry have been numerous, including:

  • Facilitated regular follow-up of those experiencing vaccine associated myopericarditis by the VHC Network
  • Led to the development of the CDC case definitions of suspect, probable or confirmed vaccine associated myopericarditis
  • Data from the registry and 16 additional cases of ischemic heart disease prompted adjustment of screening process such that any patient with a history of prior cardiac disease is generally excluded from pre-deployment vaccination (but may be considered for post-exposure prophylactic vaccination).
  • Prompted the development and subsequent revision of management guidelines, including the extension of limited duty profiles from 3 months to 6 months (http://www.smallpox.mil/documents/1184Myopericarditis Algorithm.pdf, http://www.smallpox.mil/event/cardiac.asp
  • Prompted collaborative prospective research initiatives (VHC Network & WRAMC Department of Allergy-Immunology, University of Washington, Centers for Disease Control & Prevention)
    • 6-18 month long term follow-up of Vaccine Associated Myopericarditis registry patients
    • A Pilot Study: Smallpox/Influenza Vaccination and Myopericardial Injury/Inflammation (evaluation of clinical and genetic risk factors and the inflammatory immune response)

The Walter Reed VHC Network and CDC are continuing to monitor these patients and catalogue them in the registry to further define risk factors and the natural history of affected patients.