Christine G. Casey

Myocarditis, Pericarditis, and Dilated Cardiomyopathy after Smallpox Vaccination among Civilians in the United States, January-October 2003

Myocarditis was reported after smallpox vaccination in Europe and Australia, but no association had been reported with the US vaccine. We conducted surveillance to describe and determine the frequency of myocarditis and/or pericarditis (myo/pericarditis) among civilians vaccinated during the US smallpox vaccination program between January and October 2003. We developed surveillance case definitions for myocarditis, pericarditis, and dilated cardiomyopathy after smallpox vaccination. We identified 21 myo/pericarditis cases among 37,901 vaccinees (5.5 per 10,000); 18 (86%) were revacinees, 14 (67%) were women, and the median age was 48 years (range, 25-70 years). The median time from vaccination to onset of symptoms was 11 days (range, 2-42 days). Myo/pericarditis severity was mild, with no fatalities, although 9 patients (43%) were hospitalized. Three additional vaccinees were found to have dilated cardiomyopathy, recognized within 3 months after vaccination. We describe an association between smallpox vaccination, using the US vaccinia strain, and myo/pericarditis among civilians.

Causality assessment of adverse events reported to the Vaccine Adverse Event Reporting System (VAERS).

UNLABELLED Adverse events following immunization (AEFI) reported to the national Vaccine Adverse Event Reporting System (VAERS) represent true causally related events, as well as events that are temporally, but not necessarily causally related to vaccine. OBJECTIVE We sought to determine if the causal relationships between the vaccine and the AEFI reported to VAERS could be assessed through expert review. DESIGN A stratified random sample of 100 VAERS reports received in 2004 contained 13 fatal cases, 19 cases with non-fatal disabilities, 39 other serious non-fatal cases and 29 non-serious cases. Experts knowledgeable about vaccines and clinical outcomes, reviewed each VAERS report and available medical records. MAIN OUTCOME MEASURES Modified World Health Organization criteria were used to classify the causal relationship between vaccines and AEFI as definite, probable, possible, unlikely or unrelated. Five independent reviewers evaluated each report. If they did not reach a majority agreement on causality after initial review, the report was discussed on a telephone conference to achieve agreement. RESULTS 108 AEFIs were identified in the selected 100 VAERS reports. After initial review majority agreement was achieved for 83% of the AEFI and 17% required further discussion. In the end, only 3 (3%) of the AEFI were classified as definitely causally related to vaccine received. Of the remaining AEFI 22 (20%) were classified as probably and 22 (20%) were classified as possibly related to vaccine received; a majority (53%) were classified as either unlikely or unrelated to a vaccine received. CONCLUSIONS Using VAERS reports and additional documentation, causality could be assessed by expert review in the majority of VAERS reports. Assessment of VAERS reports identified that causality was thought to be probable or definite in less than one quarter of reports, and these were dominated by local reactions, allergic reactions, or symptoms known to be associated with the vaccine administered.

Generalized Vaccinia, Progressive Vaccinia, and Eczema Vaccinatum Are Rare following Smallpox (Vaccinia) Vaccination: United States Surveillance, 2003

Generalized vaccinia (GV), progressive vaccinia (PV), and eczema vaccinatum (EV) are adverse reactions following smallpox vaccination. We investigated all reports suggestive of GV, PV, or EV among United States civilian smallpox vaccinees during 2003 and applied standard case definitions. We identified 29 reports of possible GV among 38,440 vaccinees; 2 (7%) of the reports met the case definition. One case of GV was confirmed by identifying vaccinia from a lesion distant from the vaccine site using polymerase chain reaction. The other case was classified as probable GV, because confirmatory testing was not done. We identified 3 potential EV cases and 7 potential PV cases, none of which met the standard case definition. GV, PV, and EV were rare or absent following smallpox vaccination after careful screening of potential vaccinees. GV may be difficult to distinguish from other rashes, and confirmatory testing is recommended. Careful prevaccination screening probably contributed to the low incidence of these adverse reactions following smallpox vaccination.

Dermatological Lesions near the Smallpox Vaccination Site after Scab Detachment

Lesions arising after scab detachment at the smallpox vaccination site have been described in the medical literature. We investigated reports of postscab lesions among US civilian volunteers vaccinated against smallpox from January through August 2003. We conducted enhanced surveillance, using a standard questionnaire, for reports of skin lesions appearing at or near the smallpox vaccination site after scab detachment. We identified 21 reports; 19 of the case patients responded to our questionnaire. The lesions (scab and/or fluid) of 7 case patients were tested for vaccinia virus by use of polymerase chain reaction and/or immunohistochemistry; all were found to be negative. We contacted 18 case patients 11 months after the initial lesion appearance; 10 (56%) of the 18 reported having another lesion appear after the initial postscab lesion had resolved. Lesions were heterogeneous in morphology, clinical appearance, and histology. The evidence from our case series and follow-up suggests that these lesions are self-limited, without significant clinical sequelae.