Death and serious illness following influenza vaccination: a multidisciplinary investigation.

PURPOSE: To evaluate a possible association between influenza vaccination and four deaths and four serious illnesses among 114 recent influenza vaccinees in a long-term care facility (LTCF) and two deaths from a nearby physician's office. All had received vaccine from the same lot (Lot A). METHODS: Field investigation including (1) a retrospective cohort study among LTCF residents who received Lot A or other influenza vaccine, (2) review of medical records of cases of death or serious illness, (3) active surveillance of deaths among 1500 community based Lot A vaccinees and (4) laboratory testing of vaccine from available Lot A vials. RESULTS: Medical record reviews showed no common clinical syndrome or cause of death. Laboratory testing of Lot A samples revealed no evidence of tampering and no differences compared to an unrelated lot. The risk of death or hospitalization was not significantly different between persons who received Lot A versus a comparison lot, Lot B (incidence rate ratio (IRR) = 0.9, 95%CI = 0.3-3.3). CONCLUSIONS: There was no clinical or biological evidence pointing to inherent vaccine safety issues, nor was there a detectable increased risk of death or hospitalization among persons vaccinated with Lot A. Lot specific clustering of adverse events (AEs) may reflect medical events causally unrelated to vaccination. Rapid investigations of potential AEs are important to ensure vaccine safety and to maintain public and healthcare provider confidence in vaccines.

Impact of the US Two-dose Varicella Vaccination Program on the Epidemiology of Varicella Outbreaks: Data from Nine States, 2005-2012.

BACKGROUND: A routine 2-dose varicella vaccination program was adopted in 2007 in the US to help further decrease varicella disease and prevent varicella outbreaks. We describe trends and characteristics of varicella outbreaks reported to the Centers for Disease Control and Prevention (CDC) during 2005-2012 from 9 states. METHODS: Data on varicella outbreaks collected by 9 state health departments were submitted to CDC using the CDC outbreak reporting worksheet. Information was collected on dates of the outbreak, outbreak setting and number of cases by outbreak; aggregate data were provided on the numbers of outbreak-related cases by age group, vaccination status and laboratory confirmation. RESULTS: Nine hundred and twenty-nine outbreaks were reported from the 6 states, which provided data for each year during 2005-2012. Based on data from these 6 states, the number of outbreaks declined by 78%, decreasing from 147 in 2005 to 33 outbreaks in 2012 (P = 0.0001). There were a total of 1015 varicella outbreaks involving 13,595 cases reported by the 9 states from 2005 to 2012. The size and duration of outbreaks declined significantly over time (P < 0.001). The median size of outbreaks was 12, 9 and 7 cases and median duration of outbreaks was 38, 35 and 26 days during 2005-2006, 2007-2009 and 2010-2012, respectively. Majority of outbreaks (95%) were reported from schools, declining from 97% in 2005-2006 to 89% in 2010-2012. Sixty-five percent of outbreak-related cases occurred among 5-year to 9-year olds, with the proportion declining from 76% in 2005-2006 to 45% during 2010-2012. CONCLUSIONS: The routine 2-dose varicella vaccination program appears to have significantly reduced the number, size and duration of varicella outbreaks in the US.

rotavirus-coded deaths in children, United States, 1999-2007.

The introduction of specific International Classification of Diseases-10th revision code for rotavirus in 1999 prompted us to examine the US mortality data for 1999-2007 to validate rotavirus-coded deaths. Of 38 rotavirus-coded deaths identified in the national multiple cause-of-death database, results of laboratory testing could be obtained for 21 deaths, all of which had confirmation of rotavirus by either microbiologic or histopathologic testing.

Measles outbreak associated with an international youth sporting event in the United States, 2007.

BACKGROUND: Despite elimination of endemic measles in the United States (US), outbreaks associated with imported measles continue to occur. In 2007, the initiation of a multistate measles outbreak was associated with an imported case occurring in a participant at an international youth sporting event held in Pennsylvania. METHODS: Case finding and contact tracing were conducted. Control measures included isolating ill persons and administering postexposure prophylaxis to exposed persons without documented measles immunity. Laboratory evaluation of suspected cases and contacts included measles serologic testing, viral culture, detection of viral RNA by reverse-transcription polymerase chain reaction, and viral genotyping. RESULTS: The index case occurred in a child from Japan aged 12 years. Contact tracing among 1250 persons in 8 states identified 7 measles cases; 5 (71%) cases occurred among persons without documented measles vaccination. Epidemiologic and laboratory investigation supported a single chain of transmission, linking the outbreak to contemporaneous measles virus genotype D5 transmission in Japan. Of the 471 event participants, 193 (41%) lacked documentation of presumed measles immunity, 94 (49%) of 193 were US-resident adults, 19 (10%) were non-US-resident adults (aged >18 years), and 80 (41%) were non-US-resident children. DISCUSSION: Measles outbreaks associated with imported disease are likely to continue in the US. Participants in international events, international travelers, and persons with routine exposure to such travelers might be at greater risk of measles. To reduce the impact of imported cases, high measles, mumps, and rubella vaccine coverage rates should be maintained throughout the US, and support should continue for global measles control and elimination.