Influenza activity - United States, 2014-15 season and composition of the 2015-16 influenza vaccine.

During the 2014-15 influenza season in the United States, influenza activity increased through late November and December before peaking in late December. Influenza A (H3N2) viruses predominated, and the prevalence of influenza B viruses increased late in the season. This influenza season, similar to previous influenza A (H3N2)-predominant seasons, was moderately severe with overall high levels of outpatient illness and influenza-associated hospitalization, especially for adults aged ≥65 years. The majority of circulating influenza A (H3N2) viruses were different from the influenza A (H3N2) component of the 2014-15 Northern Hemisphere seasonal vaccines, and the predominance of these drifted viruses resulted in reduced vaccine effectiveness. This report summarizes influenza activity in the United States during the 2014-15 influenza season (September 28, 2014-May 23, 2015) and reports the recommendations for the components of the 2015-16 Northern Hemisphere influenza vaccine.

Update: Influenza activity--United States, September 28, 2014-February 21, 2015.

Influenza activity in the United States began to increase in mid-November, remained elevated through February 21, 2015, and is expected to continue for several more weeks. To date, influenza A (H3N2) viruses have predominated overall. As has been observed in previous seasons during which influenza A (H3N2) viruses predominated, adults aged ≥65 years have been most severely affected. The cumulative laboratory-confirmed influenza-associated hospitalization rate among adults aged ≥65 years is the highest recorded since this type of surveillance began in 2005. This age group also accounts for the majority of deaths attributed to pneumonia and influenza. The majority of circulating influenza A (H3N2) viruses are different from the influenza A (H3N2) component of the 2014-15 Northern Hemisphere seasonal vaccines, and the predominance of these antigenically and genetically drifted viruses has resulted in reduced vaccine effectiveness. This report summarizes U.S. influenza activity* since September 28, 2014, and updates the previous summary.

Influenza activity - United States, 2013-14 season and composition of the 2014-15 influenza vaccines.

During the 2013-14 influenza season in the United States, influenza activity increased through November and December before peaking in late December. Influenza A (H1N1)pdm09 (pH1N1) viruses predominated overall, but influenza B viruses and, to a lesser extent, influenza A (H3N2) viruses also were reported in the United States. This influenza season was the first since the 2009 pH1N1 pandemic in which pH1N1 viruses predominated and was characterized overall by lower levels of outpatient illness and mortality than influenza A (H3N2)-predominant seasons, but higher rates of hospitalization among adults aged 50-64 years compared with recent years. This report summarizes influenza activity in the United States for the 2013-14 influenza season (September 29, 2013-May 17, 2014†) and reports recommendations for the components of the 2014-15 Northern Hemisphere influenza vaccines.

Update: influenza activity - United States, September 29, 2013-February 8, 2014.

Influenza activity in the United States began to increase in mid-November and remained elevated through February 8, 2014. During that time, influenza A (H1N1)pdm09 (pH1N1) viruses predominated overall, while few B and A (H3N2) viruses were detected. This report summarizes U.S. influenza activity* during September 29, 2013-February 8, 2014, and updates the previous summary.

Influenza-associated pediatric deaths in the United States, 2004-2012.

BACKGROUND: Influenza-associated deaths in children occur annually. We describe the epidemiology of influenza-associated pediatric deaths from the 2004-2005 through the 2011-2012 influenza seasons. METHODS: Deaths in children <18 years of age with laboratory-confirmed influenza virus infection were reported to the Centers for Disease Control and Prevention by using a standard case report form to collect data on demographic characteristics, medical conditions, clinical course, and laboratory results. Characteristics of children with no high-risk medical conditions were compared with those of children with high-risk medical conditions. RESULTS: From October 2004 through September 2012, 830 pediatric influenza-associated deaths were reported. The median age was 7 years (interquartile range: 1-12 years). Thirty-five percent of children died before hospital admission. Of 794 children with a known medical history, 43% had no high-risk medical conditions, 33% had neurologic disorders, and 12% had genetic or chromosomal disorders. Children without high-risk medical conditions were more likely to die before hospital admission (relative risk: 1.9; 95% confidence interval: 1.6-2.4) and within 3 days of symptom onset (relative risk: 1.6; 95% confidence interval: 1.3-2.0) than those with high-risk medical conditions. CONCLUSIONS: Influenza can be fatal in children with and without high-risk medical conditions. These findings highlight the importance of recommendations that all children should receive annual influenza vaccination to prevent influenza, and children who are hospitalized, who have severe illness, or who are at high risk of complications (age <2 years or with medical conditions) should receive antiviral treatment as early as possible.

Surveillance for influenza during the 2009 influenza A (H1N1) pandemic-United States, April 2009-March 2010.

The emergence in April 2009 and subsequent spread of the 2009 pandemic influenza A (H1N1) virus resulted in the first pandemic of the 21st century. This historic event was associated with unusual patterns of influenza activity in terms of the timing and persons affected in the United States throughout the summer and fall months of 2009 and the winter of 2010. The US Influenza Surveillance System identified 2 distinct waves of pandemic influenza H1N1 activity--the first peaking in June 2009, followed by a second peak in October 2009. All influenza surveillance components showed levels of influenza activity above that typically seen during late summer and early fall. During this period, influenza activity reached its highest level during the week ending 24 October 2009. This report summarizes US influenza surveillance data from 12 April 2009 through 27 March 2010.

2009 Pandemic influenza A (H1N1) deaths among children--United States, 2009-2010.

The 2009 pandemic influenza A (H1N1) (pH1N1) virus emerged in the United States in April 2009 (1) and has since caused significant morbidity and mortality worldwide (2-6). We compared pandemic influenza A (H1N1) (pH1N1)-associated deaths occurring from 15 April 2009 through 23 January 2010 with seasonal influenza-associated deaths occurring from 1 October 2007 through 14 April 2009, a period during which data collected were most comparable. Among 317 children who died of pH1N1-associated illness, 301 (95%) had a reported medical history. Of those 301, 205 (68%) had a medical condition associated with an increased risk of severe illness from influenza. Children who died of pH1N1-associated illness had a higher median age (9.4 vs 6.2 years; P<.01) and longer time from onset of symptoms to death (7 vs 5 days, P<.01) compared with children who died of seasonal influenza-associated illness. The majority of pediatric deaths from pH1N1 were in older children with high-risk medical conditions. Vaccination continues to be critical for all children, especially those at increased risk of influenza-related complications.

Influenza-associated mortality among children - United States: 2007-2008.

BACKGROUND: Since October 2004, pediatric influenza-associated deaths have been a nationally notifiable condition. To further investigate the bacterial organisms that may have contributed to death, we systematically collected information about bacterial cultures collected at non-sterile sites and about the timing of Staphylococcus aureus specimen collection relative to hospital admission. METHODS: We performed a retrospective, descriptive study of all reported influenza-associated pediatric deaths in 2007-2008 influenza season in the United States. RESULTS: During the 2007-2008 influenza season, 88 influenza-associated pediatric deaths were reported. The median age was 5 (range 29 days - 17 years); 48% were <5 years of age. The median time from symptom onset to death was 4 days (range 0-64 days). S. aureus was identified at a sterile site or at a non-sterile site in 20 (35%) of the 57 children with specimens collected from these sites; in 17 (85%) of these children, specimens yielding S. aureus were obtained within three days of inpatient admission. These 17 children were older (10 versus 4 years, median; P < 0·05) and less likely to have a high-risk medical condition (P < 0·05) than children with cultures from the designated sites that did not grow S. aureus. CONCLUSIONS: S. aureus continues to be the most common bacteria isolated from children with influenza-associated mortality. S. aureus isolates were associated with older age and lack of high-risk medical conditions. Healthcare providers should consider influenza co-infections with S. aureus when empirically treating children with influenza and severe respiratory illness.

Influenza-associated pediatric mortality in the United States: increase of Staphylococcus aureus coinfection.

OBJECTIVE: Pediatric influenza-associated death became a nationally notifiable condition in the United States during 2004. We describe influenza-associated pediatric mortality from 2004 to 2007, including an increase of Staphylococcus aureus coinfections. METHODS: Influenza-associated pediatric death is defined as a death of a child who is younger than 18 years and has laboratory-confirmed influenza. State and local health departments report to the Centers for Disease Control and Prevention demographic, clinical, and laboratory data on influenza-associated pediatric deaths. RESULTS: During the 2004-2007 influenza seasons, 166 influenza-associated pediatric deaths were reported (n = 47, 46, and 73, respectively). Median age of the children was 5 years. Children often progressed rapidly to death; 45% died within 72 hours of onset, including 43% who died at home or in an emergency department. Of 90 children who were recommended for influenza vaccination, only 5 (6%) were fully vaccinated. Reports of bacterial coinfection increased substantially from 2004-2005 to 2006-2007 (6%, 15%, and 34%, respectively). S aureus was isolated from a sterile site or endotracheal tube culture in 1 case in 2004-2005, 3 cases in 2005-2006, and 22 cases in 2006-2007; 64% were methicillin-resistant S aureus. Children with S aureus coinfection were significantly older and more likely to have pneumonia and acute respiratory distress syndrome than those who were not coinfected. CONCLUSIONS: Influenza-associated pediatric mortality is rare, but the proportion of S aureus coinfection identified increased fivefold over the past 3 seasons. Research is needed to identify risk factors for influenza coinfection with invasive bacteria and to determine the impact of influenza vaccination and antiviral agents in preventing pediatric mortality.

Personal exposure and long-term health effects in survivors of the union carbide disaster at bhopal.

Nine years after the Bhopal methyl isocyanate disaster, we examined the effects of exposures among a cross-section of current residents and a subset of those with persistent symptoms. We estimated individual exposures by developing exposure indices based on activity, exposure duration, and distance of residence from the plant. Most people left home after the gas leak by walking and running. About 60% used some form of protection (wet cloth on face, splashing water). Mean and median values of the exposure indices showed a declining trend with increasing distance from the plant. For those subjects reporting any versus no exposure, prevalence ratios were elevated for most respiratory and nonrespiratory symptoms. We examined exposure-response relationships using exposure indices to determine which were associated with health outcomes. The index total exposure weighted for distance was associated with most respiratory symptoms, one measure of pulmonary function in the cross-sectional sample [mid-expiratory flow (FEF)(25-75), p = 0.02], and two measures of pulmonary function in the hospitalized subset [forced expiratory volume (FEV)(1), p = 0.02; FEF(25-75), p = 0.08). Indices that correlated with FEV(1) and forced vital capacity in the hospitalized subset did not correlate with the cross-sectional sample, and most indices (except total exposure) that correlated with the hospitalized subset did not correlate with the cross-sectional sample. Incorporation of distance into every index increased the number of symptoms associated; an improvement was also noted in the strength of the association for respiratory symptoms, but not for pulmonary function. The sum of duration (p = 0.02) and total exposure (p = 0.03) indices independently demonstrated stronger associations with percent predicted FEF(25-75) than the distance variable (p = 0.04). The results show that total exposure weighted for distance has met the criteria for a successful index by being associated with most respiratory symptoms as well as FEF(25-75), features of obstructive airways disease.

The Union Carbide disaster in Bhopal: a review of health effects.

The authors have reviewed studies of human health effects that resulted from exposure to methyl isocyanate gas that leaked from the Union Carbide plant in Bhopal, India, in 1984. The studies were conducted during both the early and late recovery periods. Major organs exposed were the eyes, respiratory tract, and skin. Although mortality was initially high, it declined over time, but remained elevated among the most severely exposed population. Studies conducted during the early recovery period focused primarily on ocular and respiratory systems. Major findings included acute irritant effects on the eyes and respiratory tract. In follow-up studies, investigators observed persistent irritant effects, including ocular lesions and respiratory impairment. Studies conducted during the late recovery period focused on various systemic health endpoints. Significant neurological, reproductive, neurobehavioral, and psychological effects were also observed. Early and late recovery period studies suffered from several clinical and epidemiological limitations, including study design, bias, and exposure classification. The authors herein recommend long-term monitoring of the affected community and use of appropriate methods of investigation that include well-designed cohort studies, case-control studies for rare conditions, characterization of personal exposure, and accident analysis to determine the possible components of the gas cloud.

Advancing public health through the assessment initiative.

The CDC Assessment Initiative provided funds to six states to promote the development of innovative partnerships between traditional public health agencies and other public and private partners. Novel and creative approaches and methods of assessment were developed to monitor progress toward achieving measurable national, state, and community health objectives. In this article, the strategies and accomplishments of the participant states are summarized.