Rates and risk factors associated with hospitalization for pneumonia with ICU admission among adults.

BACKGROUND: Pneumonia poses a significant burden to the U.S. health-care system. However, there are few data focusing on severe pneumonia, particularly cases of pneumonia associated with specialized care in intensive care units (ICU). METHODS: We used administrative and electronic medical record data from six integrated health care systems to estimate rates of pneumonia hospitalizations with ICU admissions among adults during 2006 through 2010. Pneumonia hospitalization was defined as either a primary discharge diagnosis of pneumonia or a primary discharge diagnosis of sepsis or respiratory failure with a secondary diagnosis of pneumonia in administrative data. ICU admissions were collected from internal electronic medical records from each system. Comorbidities were identified by ICD-9-CM codes coded during the current pneumonia hospitalization, as well as during medical visits that occurred during the year prior to the date of admission. RESULTS: We identified 119,537 adult hospitalizations meeting our definition for pneumonia. Approximately 19% of adult pneumonia hospitalizations had an ICU admission. The rate of pneumonia hospitalizations requiring ICU admission during the study period was 76 per 100,000 population/year; rates increased for each age-group with the highest rates among adults aged ≥85 years. Having a co-morbidity approximately doubled the risk of ICU admission in all age-groups. CONCLUSIONS: Our study indicates a significant burden of pneumonia hospitalizations with an ICU admission among adults in our cohort during 2006 through 2010, especially older age-groups and persons with underlying medical conditions. These findings reinforce current strategies aimed to prevent pneumonia among adults.

Cross-reactive antibody responses to the 2009 pandemic H1N1 influenza virus.

BACKGROUND: A new pandemic influenza A (H1N1) virus has emerged, causing illness globally, primarily in younger age groups. To assess the level of preexisting immunity in humans and to evaluate seasonal vaccine strategies, we measured the antibody response to the pandemic virus resulting from previous influenza infection or vaccination in different age groups. METHODS: Using a microneutralization assay, we measured cross-reactive antibodies to pandemic H1N1 virus (2009 H1N1) in stored serum samples from persons who either donated blood or were vaccinated with recent seasonal or 1976 swine influenza vaccines. RESULTS: A total of 4 of 107 persons (4%) who were born after 1980 had preexisting cross-reactive antibody titers of 40 or more against 2009 H1N1, whereas 39 of 115 persons (34%) born before 1950 had titers of 80 or more. Vaccination with seasonal trivalent inactivated influenza vaccines resulted in an increase in the level of cross-reactive antibody to 2009 H1N1 by a factor of four or more in none of 55 children between the ages of 6 months and 9 years, in 12 to 22% of 231 adults between the ages of 18 and 64 years, and in 5% or less of 113 adults 60 years of age or older. Seasonal vaccines that were formulated with adjuvant did not further enhance cross-reactive antibody responses. Vaccination with the A/New Jersey/1976 swine influenza vaccine substantially boosted cross-reactive antibodies to 2009 H1N1 in adults. CONCLUSIONS: Vaccination with recent seasonal nonadjuvanted or adjuvanted influenza vaccines induced little or no cross-reactive antibody response to 2009 H1N1 in any age group. Persons under the age of 30 years had little evidence of cross-reactive antibodies to the pandemic virus. However, a proportion of older adults had preexisting cross-reactive antibodies.

Herpes zoster and exposure to the varicella zoster virus in an era of varicella vaccination.

OBJECTIVES: We performed a case-control study to determine if participants with herpes zoster had fewer contacts with persons with varicella or zoster, and with young children, to explore the hypothesis that exposure to persons with varicella zoster virus (VZV) results in "immune boosting." METHODS: Participants were patients of the multispecialty Marshfield Clinic in Wisconsin. We identified patients aged 40 to 79 years with a new diagnosis of zoster from August 2000 to July 2005. We frequency matched control participants to case participants for age. We confirmed diagnoses by chart review and assessed exposures by interview. RESULTS: Interviews were completed by 633 of 902 eligible case participants (70.2%) and 655 of 1149 control participants (57.0%). The number of varicella contacts was not associated with zoster; there was no trend even at the highest exposure level (3 or more contacts). Similarly, there was no association with exposure to persons with zoster or to children, or with workplace exposures. CONCLUSIONS: Although exposure to VZV in our study was relatively low, the absence of a relationship with zoster reflects the uncertain influence of varicella circulation on zoster epidemiology.

Influenza Illness and Hospitalizations Averted by Influenza Vaccination in the United States, 2005-2011.

CONTEXT: The goal of influenza vaccination programs is to reduce influenza-associated disease outcomes. Therefore, estimating the reduced burden of influenza as a result of vaccination over time and by age group would allow for a clear understanding of the value of influenza vaccines in the US, and of areas where improvements could lead to greatest benefits. OBJECTIVE: To estimate the direct effect of influenza vaccination in the US in terms of averted number of cases, medically-attended cases, and hospitalizations over six recent influenza seasons. DESIGN: Using existing surveillance data, we present a method for assessing the impact of influenza vaccination where impact is defined as either the number of averted outcomes or as the prevented disease fraction (the number of cases estimated to have been averted relative to the number of cases that would have occurred in the absence of vaccination). RESULTS: We estimated that during our 6-year study period, the number of influenza illnesses averted by vaccination ranged from a low of approximately 1.1 million (95% confidence interval (CI) 0.6-1.7 million) during the 2006-2007 season to a high of 5 million (CI 2.9-8.6 million) during the 2010-2011 season while the number of averted hospitalizations ranged from a low of 7,700 (CI 3,700-14,100) in 2009-2010 to a high of 40,400 (CI 20,800-73,000) in 2010-2011. Prevented fractions varied across age groups and over time. The highest prevented fraction in the study period was observed in 2010-2011, reflecting the post-pandemic expansion of vaccination coverage. CONCLUSIONS: Influenza vaccination programs in the US produce a substantial health benefit in terms of averted cases, clinic visits and hospitalizations. Our results underscore the potential for additional disease prevention through increased vaccination coverage, particularly among nonelderly adults, and increased vaccine effectiveness, particularly among the elderly.

Lack of association between acellular pertussis vaccine and seizures in early childhood.

OBJECTIVES: Receipt of diphtheria-tetanus-whole-cell pertussis vaccine (diphtheria-tetanus toxoids-pertussis [DTP]) is associated with seizures. Limited population-based studies have been conducted on the risk for seizures after receipt of diphtheria-tetanus-acellular pertussis vaccine (diphtheria-tetanus-acellular pertussis [DTaP]). METHODS: We conducted a retrospective study from 1997-2006 by using risk-interval cohort and self-controlled case series (SCCS) analyses on automated data at 7 managed care organizations that participate in the Vaccine Safety Datalink (VSD). Eligible children included the 1997-2006 VSD cohort of patients who were aged 6 weeks to 23 months and had not received DTP during the study period. A seizure event (febrile or afebrile) was defined by International Classification of Diseases, Ninth Revision, Clinical Modification diagnoses assigned to an inpatient or emergency department setting. The exposed period was composed of a predefined 4 person-days after each DTaP dose. All of the remaining observation periods outside the exposed periods were categorized as unexposed. The risk-interval cohort method compared the incidence of seizures between the exposed and unexposed cohorts. In the SCCS method, the comparison was performed between the same patient's exposed and unexposed period. RESULTS: We identified 7191 seizure events among 433,654 children. The adjusted incidence rate ratio of seizures across all doses was 0.87 in cohort analysis and 0.91 in SCCS analysis. CONCLUSIONS: We did not observe an increased risk for seizures after DTaP vaccination among children who were aged 6 weeks to 23 months. These findings provide reassuring evidence on the safety of DTaP with respect to seizures.

Building the infrastructure for nationwide cancer surveillance and control--a comparison between the National Program of Cancer Registries (NPCR) and the Surveillance, Epidemiology, and End Results (SEER) Program (United States).

OBJECTIVE: In preparation for jointly publishing official government cancer statistics, the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute (NCI) compared incidence rates from NCI's Surveillance Epidemiology and End Results (SEER) Program and CDC's National Program of Cancer Registries (NPCR). METHODS: Data for 1999 covering 78% of the US population were obtained from SEER and selected NPCR registries that met high quality data criteria. Incidence rates (per 100,000 population) were age-adjusted to the 2000 US standard population, and 95% gamma confidence intervals were estimated. RESULTS: NPCR rates for all sites combined were higher than SEER rates (males: NPCR 553.6, SEER 538.7; females: NPCR 420.8, SEER 412.5), but rates for specific cancer sites varied by registry program. Rates for colon cancer (males: NPCR 47.0, SEER 42.7; females: NPCR 36.5, SEER 33.8) and tobacco-related cancers were higher in NPCR than SEER. In contrast, NPCR rates were lower than SEER rates for cancers of the female breast (NPCR 134.0, SEER 135.9), prostate (NPCR 162.0, SEER 170.2), and melanoma as well as for cancers more common among Asians and Pacific Islanders (e.g., stomach cancer). CONCLUSIONS: Rate differences may arise from population differences in socio-demographic characteristics, screening use, health behaviors, exposure to cancer causing agents or registry operations factors.

Prevalence of anti-gelatin IgE antibodies in people with anaphylaxis after measles-mumps rubella vaccine in the United States.

OBJECTIVE: Anaphylaxis after immunization, although rare, is serious and potentially life-threatening. Understanding risk factors for this reaction is therefore important. Gelatin is added to many vaccines as a heat stabilizer. Japanese researchers have demonstrated a strong association between immediate hypersensitivity reactions to measles, mumps, rubella, varicella, and Japanese encephalitis immunizations and subsequent detection of anti-gelatin immunoglobulin E (IgE) antibodies. They suggested that previous receipt by these patients of diphtheria-tetanus-acellular pertussis vaccines with trace amounts of gelatin was responsible for the sensitization. We aimed to assess whether a similar association exists for vaccinees in the United States who reported anaphylaxis after receipt of measles-mumps-rubella (MMR) or measles vaccines and to review recent trends in reporting of hypersensitivity reactions. METHODS: We conducted a retrospective case-control study. Cases of anaphylaxis that met a predefined case definition were identified from the US Vaccine Adverse Event Reporting System (VAERS). Mayo Clinic patients who received MMR vaccine uneventfully served as controls. The study subjects were interviewed to obtain the history of allergies. Sera from study subjects and their matched controls were tested for IgE antibodies to gelatin, whole egg, and vaccine viral antigens using solid-phase radioimmunoassay. Data from the Biologics Surveillance System on annual numbers of doses of MMR and varicella vaccines distributed in the United States were used to evaluate possible changes in reporting of selected allergic adverse events. RESULTS: Fifty-seven study subjects were recruited into the study and interviewed. Of these, 22 provided serum samples for IgE testing. Twenty-seven subjects served as a comparison group and provided a sample for IgE testing; 21 of these completed an allergy history questionnaire. Self-reported history of food allergies was present more frequently in the interviewed study subjects than in the controls, whereas the proportions of people with other characteristics were similar in both groups. None of the interviewed people had a history of food allergy to gelatin. The level of anti-gelatin IgE antibodies was significantly higher among study subjects than among controls, whereas the levels of IgE antibodies against egg and all 3 viral antigens did not differ significantly. Of 22 study subjects, 6 (27%) tested positive for anti-gelatin IgE, whereas none of the 27 controls did. The rate of anaphylactic reactions reported to VAERS after measles virus-containing immunization in the United States between 1991 and 1997 is 1.8 per 1 million doses distributed. No substantial increase in the number of reported allergic events after frequently used gelatin containing MMR and varicella vaccines could be observed during the first 4 years (1997-2000) since the introduction of diphtheria-tetanus-acellular pertussis vaccines for use in infancy. CONCLUSION: Anaphylactic reactions to MMR in the United States are rare. The reporting rate has the same order of magnitude as estimates from other countries. Almost one fourth of patients with reported anaphylaxis after MMR seem to have hypersensitivity to gelatin in the vaccine. They may be at higher risk of developing anaphylaxis to subsequent doses of other gelatin-containing vaccines. These people should seek an allergy evaluation before such immunization.