Publications (41)242.91 Total impact
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Article: A Prospective Study of Agents Associated with Acute Respiratory Infection among Young American Indian Children.
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ABSTRACT: BACKGROUND:: Native American children have higher rates of morbidity associated with acute respiratory infection than children in the general United States population, yet detailed information is lacking regarding their principal clinical presentations and infectious etiologies. METHODS:: We pursued a comprehensive molecular survey of bacteria and viruses in nasal wash specimens from children with acute respiratory disease collected prospectively over one year (January 1 through December 31, 2009) from 915 Navajo and White Mountain Apache children in their second or third year of life who had been enrolled in an efficacy study of an RSV monoclonal antibody in the first year of life. RESULTS:: During the surveillance period, 1476 episodes of disease were detected in 669 children. Rates of outpatient and inpatient lower respiratory tract illness were 391 and 79 per 1000 child-years, respectively, and were most commonly diagnosed as pneumonia. Potential pathogens were detected in 88% of specimens. Viruses most commonly detected were respiratory syncytial virus (RSV) and human rhinovirus (HRV); 2009 pandemic influenza A (H1N1) illnesses primarily occurred in the fall. Streptococcus pneumoniae was detected in 60% of subjects; only HRV was significantly associated with S. pneumoniae carriage. The presence of influenza virus, HRV, or S. pneumoniae was not associated with increased risk for lower respiratory tract involvement or hospitalization. CONCLUSIONS:: Acute lower respiratory illnesses occur at disproportionately high rates among young American Indian children, and are associated with a range of common pathogens. This study provides critical evidence to support reducing the disproportionate burden of acute respiratory disease among young Native Americans.The Pediatric Infectious Disease Journal 03/2013; · 3.58 Impact Factor -
Article: Lack of Non-Specific Protection Against All-Cause, Non-Rotavirus Gastroenteritis by Vaccination with Orally Administered Rotavirus Vaccine.
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ABSTRACT: OBJECTIVES:: Acute gastroenteritis (AGE) is recognized as a global, common threat to child survival, especially in developing countries. Rotavirus, in particular, has been implicated as a leading cause of severe AGE; however, there are numerous other pathogens that also cause AGE. Several studies have demonstrated that oral vaccination against rotavirus has generated the unanticipated benefit of protecting against AGE caused by non-rotavirus pathogens. METHODS:: Safety and efficacy of the pentavalent bovine-human reassortant rotavirus vaccine (PRV, RotaTeq™, Merck & Co., Inc., Whitehouse Station, NJ) were studied in multiple populations including children of the Navajo and White Mountain Apache (N/WMA) tribes in the southwest United States. Stool specimens were collected from children with AGE and tested for rotavirus using an enzyme immunoassay. Analyses were conducted to detect the presence or absence of a vaccine-effect on incidence, severity and duration of AGE in which rotavirus was not detected. RESULTS:: The majority of AGE (N = 558: 472 non-rotavirus vs. 86 rotavirus) occurred between August 2002 and March 2004 among children ranging from ages 4-23 months. The incidence of non-rotavirus AGE was similar by vaccine groups with an incidence rate ratio of 1.07 (IRR = vaccinated/unvaccinated, 95% CI: 0.89-1.29). The hazards of 1, 2, 3 or any AGE in which rotavirus was not detected differed little by vaccination status (p > 0.05). Duration of symptoms and severity of non-rotavirus AGE were similar by vaccine group. CONCLUSIONS:: There was no vaccine effect on frequency or severity of non-rotavirus AGE.Journal of pediatric gastroenterology and nutrition 01/2013; · 2.18 Impact Factor -
Article: The Family Spirit Trial for American Indian Teen Mothers and Their Children: CBPR Rationale, Design, Methods and Baseline Characteristics.
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ABSTRACT: The purpose of this paper is to describe the rationale, design, methods and baseline results of the Family Spirit trial. The goal of the trial is to evaluate the impact of the paraprofessional-delivered "Family Spirit" home-visiting intervention to reduce health and behavioral risks for American Indian teen mothers and their children. A community based participatory research (CBPR) process shaped the design of the current randomized controlled trial of the Family Spirit intervention. Between 2006 and 2008, 322 pregnant teens were randomized to receive the Family Spirit intervention plus Optimized Standard Care, or Optimized Standard Care alone. The Family Spirit intervention is a 43-session home-visiting curriculum administered by American Indian paraprofessionals to teen mothers from 28 weeks gestation until the baby's third birthday. A mixed methods assessment administered at nine intervals measures intervention impact on parental competence, mother's and children's social, emotional and behavioral risks for drug use, and maladaptive functioning. Participants are young (mean age = 18.1 years), predominantly primiparous, unmarried, and challenged by poverty, residential instability and low educational attainment. Lifetime and pregnancy drug use were ~2-4 times higher and ~5-6 times higher, respectively, than US All Races. Baseline characteristics were evenly distributed between groups, except for higher lifetime cigarette use and depressive symptoms among intervention mothers. If study aims are achieved, the public health field will have new evidence supporting multi-generational prevention of behavioral health disparities affecting young American Indian families and the utility of indigenous paraprofessional interventionists in under-resourced communities.Prevention Science 07/2012; 13(5):504-18. · 2.63 Impact Factor -
Article: Nontypeable pneumococcal isolates among navajo and white mountain apache communities: are these really a cause of invasive disease?
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ABSTRACT: Pneumococci could evade pneumococcal conjugate vaccines (PCV) by modifying, mutating, or deleting vaccine-serotype capsule genes or by downregulating capsule production. We sought to assess whether pneumococci that are nontypeable (NT) by the Quellung reaction truly lack capsule genes or are failing to produce capsule in vitro. We applied multilocus sequence typing and a microarray for detection of pneumococcal polysaccharide capsule biosynthesis genes to NT carriage (children aged <5 years; years 1997-2000, 2006-2008) and NT invasive disease (IPD) (all ages; years 1994-2007) isolates from Native American communities. Twenty-seven of 28 (96.4%) NT IPD isolates had sequence types (STs) typically found among typeable IPD isolates and contained whole or fragments of capsule genes that matched known serotypes; 1 NT-IPD isolate had a profile resembling NT carriage isolates. Forty-nine of 76 (64.5%) NT carriage isolates had STs that typically lack capsule genes and were similar to NT carriage isolates found globally. This is the first documentation of IPD from an NT strain confirmed to lack all known capsule genes. Most NT IPD isolates have or had the capacity to produce capsule, whereas a majority of NT carriage isolates lack this capacity. We found no evidence of pneumococcal adaptation to PCV7 via downregulation or deletion of vaccine-serotype capsule genes.The Journal of Infectious Diseases 04/2012; 206(1):73-80. · 6.41 Impact Factor -
Article: Epidemiologic and clinical features of other enteric viruses associated with acute gastroenteritis in American Indian infants.
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ABSTRACT: To investigate the viral etiology, through the use of molecular methods, of acute gastroenteritis (AGE), which is a considerable public health burden in Native American infants. From March 2002 through February 2004, AGE and non-diarrheal stools were collected from Navajo and White Mountain Apache infants who received placebo during a rotavirus vaccine trial. Case (n=247) and control (n=344) specimens were tested for enteric adenovirus, astrovirus, norovirus, rotavirus, and sapovirus with real-time polymerase chain reaction. The odds of AGE were compared with population-averaged logistic regression models. In 65% of the cases of AGE (161/247), at least one virus was detected; norovirus (n=80, 32%) and rotavirus (n=70, 28%) were the most common. A virus was detected in 38% of control specimens (132/344). Detection of "any virus" was associated with AGE (OR=3.22; 95% CI, 2.11-4.91), as was detection of norovirus (OR=2.00; 95% CI, 1.22-3.26) and rotavirus (OR=2.69; 95% CI, 1.52-4.79). This study highlights the significant burden of viral AGE in American Indian infants and identifies pathogen targets for future prevention efforts in this population.The Journal of pediatrics 02/2012; 161(1):110-5.e1. · 4.02 Impact Factor -
Article: Efficacy of a pentavalent human-bovine reassortant rotavirus vaccine against rotavirus gastroenteritis among American Indian children.
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ABSTRACT: Before the widespread use of rotavirus vaccines, rotavirus was a leading cause of gastroenteritis among children. Navajo and White Mountain Apache children suffer a disproportionate burden of severe rotavirus disease compared with the general U.S. population. We enrolled Navajo and White Mountain Apache infants in a multicenter, double-blind, placebo-controlled trial of pentavalent human-bovine reassortant rotavirus vaccine (PRV). Subjects received 3 doses of vaccine or placebo at 4 to 10 week intervals, with the first dose given between 6 and 12 weeks of age. Gastroenteritis episodes were identified by active surveillance. Disease severity was determined by a standardized scoring system. There were 509 and 494 randomized children who received vaccine and placebo, respectively. Among placebo recipients, the incidence of rotavirus gastroenteritis was 34.2 episodes/100 child-years (95% confidence interval [95% CI]: 25.8-38.9) versus 8.1 episodes/100 child-years (95% CI: 5.4-12.5) in the vaccine group. The percentage of rotavirus episodes caused by serotypes G1, G2, and G3 was 72.3%, 23.4%, and 2.1%, respectively. There were no severe rotavirus episodes among vaccinees and 4 among placebo recipients. PRV was 77.1% (95% CI: 59.7-87.6), 89.5% (95% CI: 65.9-97.9), and 82.9% (95% CI: 61.1-93.6) effective against G1-G4 rotavirus disease, severe and moderate rotavirus disease combined, and outpatient visits for rotavirus disease, respectively. The risk of adverse events was similar for the vaccine and placebo groups. PRV was highly effective in preventing rotavirus disease and related health care utilization in these American Indian infants. Vaccine efficacy and immunogenicity were similar to the overall study population enrolled in the multicenter trial.The Pediatric Infectious Disease Journal 02/2012; 31(2):184-8. · 3.58 Impact Factor -
Article: Impact of more than a decade of pneumococcal conjugate vaccine use on carriage and invasive potential in Native American communities.
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ABSTRACT: We assessed the impact of 12 years of pneumococcal conjugate vaccine (PCV7) use on pneumococcal nasopharyngeal carriage and serotype-specific invasive disease potential among Native Americans. Families were enrolled in a carriage study from 2006 to 2008; nasopharyngeal specimens and risk factor information were collected monthly for 7 visits. Pneumococcal carriage prevalence was compared with that before (1998-2000) and during (2001-2002) PCV7 introduction. We compared invasive disease incidence and carriage prevalence before and after PCV7 introduction to estimate changes in serotype-specific invasive potential. We enrolled 1077 subjects from 302 households. There was an absolute reduction in carriage prevalence of 8.0% (95% confidence interval [CI], 4.5%-11.4%) in children aged <5 years and 3.1% (95% CI, 1.1%-5.1%) in adults. In children aged <5 years, vaccine-serotype carriage prevalence decreased by 22.8% (95% CI, 20.1%-25.3%), and nonvaccine serotype (NVT) increased by 15.9% (95% CI, 12.4%-19.3%). No significant change was detected in serotype-specific invasive potential after PCV7 introduction. Pneumococcal carriage prevalence decreased in all ages since PCV7 introduction; vaccine-serotype carriage has been nearly eliminated, whereas the prevalence of NVT carriage has increased. The increase in the NVT invasive disease rate seems to be proportional to the increase in colonization prevalence.The Journal of Infectious Diseases 11/2011; 205(2):280-8. · 6.41 Impact Factor -
Article: Pneumococcal sequence type replacement among American Indian children: a comparison of pre- and routine-PCV7 eras.
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ABSTRACT: Multi-locus sequence typing (MLST) of pneumococcal isolates collected during an efficacy trial of the 7-valent pneumococcal conjugate vaccine (PCV7) among Navajo and White Mountain Apache children from 1998 to 2000 showed a non-differential expansion of pre-existing sequence types (STs) and only one capsule-switching event in the PCV7-randomized communities. PCV7 was introduced as a routine infant vaccine in October 2000. We assessed variability in PCV7 effectiveness and mechanisms of ST replacement after prolonged routine PCV7 use. We applied MLST to 267 non-vaccine type pneumococcal carriage and invasive disease isolates from Navajo and White Mountain Apache children from 2006 to 2008, and compared them to those from 1998 to 2000. Microarray was used to confirm capsule switching events. The primary mechanism of ST replacement among Navajo and White Mountain Apache children was expansion of existing STs, although introduction of new STs was an important secondary mechanism. ST199, a majority being serotype 19A, was the most common ST in both eras. Only ST193 (serotype 21) was preferentially expanding in the PCV7 era. Three examples of capsule switching were identified. No variability in vaccine effectiveness by ST was observed. We did not observe an influence of ST on PCV7 serotype-specific effectiveness, although some STs may be favored in replacement.Vaccine 11/2011; 30(13):2376-81. · 3.77 Impact Factor -
Article: Detection of G3P[3] and G3P[9] rotavirus strains in American Indian children with evidence of gene reassortment between human and animal rotaviruses.
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ABSTRACT: The distribution and evolution of human rotavirus strains is important for vaccine development and effectiveness. In settings where rotavirus vaccine coverage is high, vaccine pressure could select for replacement of common strains (similar to those included in rotavirus vaccines) with uncommon strains, some of which could be generated by reassortment between human and animal rotaviruses. Between 2002 and 2004, a phase-III rotavirus vaccine clinical trial was conducted among American Indian children of the Navajo and White Mountain Apache tribes, which are known to be at high risk for rotavirus diarrhea. We evaluated the rotavirus strains collected from study participants who received placebo during the trial to determine the distribution of rotavirus genotypes and to detect emerging strains that contribute to disease and could influence rotavirus vaccine effectiveness. Three uncommon strains of human rotavirus, two G3P[3] and one G3P[9] strains were detected in stools of children aged 3 to 6 months of age. Segments of all 11 rotavirus genes were sequenced and genotyped by comparison of cognate gene fragments with reference strains. The G3P[3] strains had similar genotypes to each other and to reference dog and cat strains. The G3P[9] strain had similar genotypes to cow, cat and dog reference strains. Genetic analyses of these three strains support the known diversity generating mechanisms of rotavirus.Journal of Medical Virology 07/2011; 83(7):1288-99. · 2.82 Impact Factor -
Article: Maternal influenza vaccination and effect on influenza virus infection in young infants.
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ABSTRACT: To assess the effect of seasonal influenza vaccination during pregnancy on laboratory-confirmed influenza in infants to 6 months of age. Nonrandomized, prospective, observational cohort study. Navajo and White Mountain Apache Indian reservations, including 6 hospitals on the Navajo reservation and 1 on the White Mountain Apache reservation. A total of 1169 mother-infant pairs with mothers who delivered an infant during 1 of 3 influenza seasons. Maternal seasonal influenza vaccination. In infants, laboratory-confirmed influenza, influenza-like illness (ILI), ILI hospitalization, and influenza hemagglutinin inhibition antibody titers. A total of 1160 mother-infant pairs had serum collected and were included in the analysis. Among infants, 193 (17%) had an ILI hospitalization, 412 (36%) had only an ILI outpatient visit, and 555 (48%) had no ILI episodes. The ILI incidence rate was 7.2 and 6.7 per 1000 person-days for infants born to unvaccinated and vaccinated women, respectively. There was a 41% reduction in the risk of laboratory-confirmed influenza virus infection (relative risk, 0.59; 95% confidence interval, 0.37-0.93) and a 39% reduction in the risk of ILI hospitalization (relative risk, 0.61; 95% confidence interval, 0.45-0.84) for infants born to influenza-vaccinated women compared with infants born to unvaccinated mothers. Infants born to influenza-vaccinated women had significantly higher hemagglutinin inhibition antibody titers at birth and at 2 to 3 months of age than infants of unvaccinated mothers for all 8 influenza virus strains investigated. Maternal influenza vaccination was significantly associated with reduced risk of influenza virus infection and hospitalization for an ILI up to 6 months of age and increased influenza antibody titers in infants through 2 to 3 months of age.Archives of pediatrics & adolescent medicine 10/2010; 165(2):104-11. · 3.73 Impact Factor -
Article: Pre- and post-conjugate vaccine epidemiology of pneumococcal serotype 6C invasive disease and carriage within Navajo and White Mountain Apache communities.
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ABSTRACT: A second-generation 13-valent pneumococcal conjugate vaccine, PCV13, was recently licensed. Although PCV13 includes serotype 6A, the usefulness of that antigen may be limited by the emergence of a new serotype, 6C, which was identified among isolates initially characterized (Quellung reaction) as serotype 6A. The epidemiology of serotype 6C prior to and after 7-valent PCV (PCV7) introduction is incompletely understood. We analyzed conventionally serotyped 6A (CS6A) pneumococci from invasive disease case patients of all ages and carriage isolates from children and adults obtained in population-based studies among Navajo and White Mountain Apache communities during 1994-2009. Samples were tested by triplex polymerase chain reaction to resolve serotypes 6C and 6A. A total of 74 invasive CS6A episodes occurred. All were retyped by polymerase chain reaction; 40 (54.1%) were serotype 6C. The mean annual incidence of serotype 6C invasive disease was 0.3 (95% confidence interval, 0.03-0.9), 0.7 (95% confidence interval, 0.2-1.3), and 1.5 (95% confidence interval, 1.0-2.1) cases per 100,000 population in the years prior to the PCV7 efficacy trial, during the time the PCV7 trial was conducted, and following PCV7 introduction and routine use, respectively (P = .01). In the routine vaccination era, 76% of invasive CS6As were serotype 6C; nearly all cases occurred in adults. The proportion of serotype 6C among CS6A carriage isolates increased from 42% to 61% to 94% in the prevaccine, early vaccine, and routine vaccination eras, respectively. In the PCV7 routine use era, virtually all serogroup 6 invasive pneumococcal disease and carriage strains among Navajo and White Mountain Apache communities are 6C. Monitoring and evaluation of this and other emerging serotypes among invasive disease and carriage isolates is warranted.Clinical Infectious Diseases 10/2010; 51(11):1258-65. · 9.15 Impact Factor -
Article: Invasive pneumococcal disease a decade after pneumococcal conjugate vaccine use in an American Indian population at high risk for disease.
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ABSTRACT: Before 7-valent pneumococcal conjugate vaccine (PCV7) introduction, invasive pneumococcal disease (IPD) rates among Navajo were several-fold those of the general US population. Only 50% of IPD cases in children involved PCV7 serotypes. We conducted active, population-based surveillance for IPD for the period 1995-2006. We documented case characteristics and serotyped the isolates. Over 12-year period, we identified 1508 IPD cases, 447 of which occurred in children aged <5 years. Rates of IPD due to vaccine serotypes among children aged <1 year, 1 to <2 years, and 2 to <5 years decreased from 210, 263, and 51 cases per 100,000 population, respectively in 1995-1997 to 0 cases in 2004-2006 (P < .001). Among adults aged > or =65 years, rates of IPD due to vaccine serotypes decreased 81% (95% confidence interval, -98% to -9%; P = .02). Rates of nonvaccine serotype IPD were unchanged in all age strata except for persons aged 18 to <40 years, among whom the rate decreased by 35% from 27 to 18 cases per 100,000 population (95% confidence interval, -57% to -1%; P = .03). Vaccine-serotype IPD has virtually been eliminated in the PCV7 era among Navajo of all ages. Overall rates of nonvaccine-serotype IPD have not increased, although increases have occurred for some individual types. Rates of all-serotype IPD among Navajo children remain 3-5-fold greater than in the general US population.Clinical Infectious Diseases 05/2010; 50(9):1238-46. · 9.15 Impact Factor -
Article: Examining correlates of methamphetamine and other drug use in pregnant American Indian adolescents.
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ABSTRACT: American Indian and Alaska Native (AI/AN) adolescents have high rates of pregnancy, as well as alcohol, marijuana, cocaine, and, increasingly, methamphetamine (meth) use. The progression of adolescent drug use to meth use could have devastating impacts on AI communities, particularly when youth are simultaneously at risk for teen childbearing. In order to inform future prevention efforts, this study explores correlates of meth use in a sample of pregnant AI teens, with a focus on sociodemographic, familial, and cultural factors and use of other drugs.American Indian and Alaska native mental health research (Online) 01/2010; 17(1):1-24. -
Article: Nasopharyngeal carriage of Streptococcus pneumoniae in Navajo and White Mountain Apache children before the introduction of pneumococcal conjugate vaccine.
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ABSTRACT: Infants and children are frequently colonized with pneumococcus. Recent nasopharyngeal acquisition of pneumococcus is thought to precede disease episodes. The increased risk of pneumococcal disease among Navajo and White Mountain Apache populations has been documented. Little is known about the dynamics of pneumococcal carriage in these populations. A group randomized, controlled trial of 7-valent conjugate pneumococcal vaccine (PnCRM7, Wyeth) was conducted on the Navajo and Apache reservations. A nasopharyngeal (NP) carriage study was nested in the trial to evaluate the impact of PnCRM7 on carriage. Children <6 years of age had NP swabs collected at enrollment and at 6 and 12 months following enrollment. We analyzed carriage data from children in control vaccine randomized communities to describe the epidemiology of pneumococcal carriage. Of the 410 participants enrolled, 92% were colonized with pneumococcus at least once during the course of the study. Sixty-three percent of NP specimens were positive for pneumococcus. The most common serotypes were 6A, 6B, nontypable, 23F, 14, 19F, 19A, and 9V. Thirty-eight percent of isolates were vaccine serotypes. Age <2 years, male sex, daycare attendance, and having a sibling colonized with pneumococcus were associated with an increased risk of carriage. The high carriage prevalence among Navajo and Apache children reflects an intense exposure to pneumococcus. The lack of modifiable risk factors for carriage highlights the importance of preventive strategies for disease control.The Pediatric Infectious Disease Journal 08/2009; 28(8):711-6. · 3.58 Impact Factor -
Article: Randomized controlled trial of a paraprofessional-delivered in-home intervention for young reservation-based American Indian mothers.
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ABSTRACT: To evaluate the efficacy of a paraprofessional-delivered, home-visiting intervention among young, reservation-based American Indian (AI) mothers on parenting knowledge, involvement, and maternal and infant outcomes. From 2002 to 2004, expectant AI women aged 12 to 22 years (n = 167) were randomized (1:1) to one of two paraprofessional-delivered, home-visiting interventions: the 25-visit "Family Spirit" intervention addressing prenatal and newborn care and maternal life skills (treatment) or a 23-visit breast-feeding/nutrition education intervention (active control). The interventions began during pregnancy and continued to 6 months postpartum. Mothers and children were evaluated at baseline and 2, 6, and 12 months postpartum. Primary outcomes included changes in mothers' parenting knowledge and involvement. Secondary outcomes included infants' social and emotional behavior; the home environment; and mothers' stress, social support, depression, and substance use. Participants were mostly teenaged, first-time, unmarried mothers living in reservation communities. At 6 and 12 months postpartum, treatment mothers compared with control mothers had greater parenting knowledge gains, 13.5 (p < .0001) and 13.9 (p < .0001) points higher, respectively (100-point scale). At 12 months postpartum, treatment mothers reported their infants to have significantly lower scores on the externalizing domain (beta = -.17, p < .05) and less separation distress in the internalizing domain (beta = -.17, p < .05). No between-group differences were found for maternal involvement, home environment, or mothers' stress, social support, depression, or substance use. This study supports the efficacy of the paraprofessional-delivered Family Spirit home-visiting intervention for young AI mothers on maternal knowledge and infant behavior outcomes. A longer, larger study is needed to replicate results and evaluate the durability of child behavior outcomes.Journal of the American Academy of Child and Adolescent Psychiatry 07/2009; 48(6):591-601. · 4.98 Impact Factor -
Article: Pneumococcal antibodies in a child with type 14 pneumococcal conjugate vaccine failure.
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ABSTRACT: We measured the concentration, opsonic activity, and avidity of serotype-specific serum antibodies in a pneumococcal conjugate vaccine (PnCRM7) efficacy trial participant who contracted serotype 14 pneumococcal bacteremia following dose 3 of PnCRM7. Controls included 18 PnCRM7- and 10 MnCC-vaccinated children without invasive pneumococcal disease (IPD). The child with vaccine failure had 4.98mcg/mL of serotype 14 antibodies 10 days before disease onset; these antibodies had greater opsonic activity and lower avidity than those of control PnCRM7 recipients. The child had no booster response to a fourth dose of PnCRM7 for most vaccine serotypes. We conclude that antibody concentration, functional activity and avidity do not predict individual protection against IPD, and immunological correlates of protection are only useful at the population level.Vaccine 02/2009; 27(12):1863-8. · 3.77 Impact Factor -
Article: Young infants can develop protective levels of neutralizing antibody after infection with respiratory syncytial virus.
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ABSTRACT: Humoral immunity protects against severe respiratory syncytial virus (RSV) disease, but the range and magnitude of antibody responses in RSV-naive children after RSV infection have not been completely defined. We evaluated RSV-neutralizing antibody and immunoglobulin G responses to RSV F and G glycoproteins in 65 RSV-naive Navajo and White Mountain Apache children aged 0-24 months who were hospitalized with RSV infection. In these children, antibody responses developed against RSV F and G and the central conserved region of RSV G. Twenty-seven of 41 infants <6 months old developed reciprocal log(2) RSV neutralizing antibody titers > or =8.0, which correlate with protection of the lower respiratory tract. Multivariate analysis demonstrated that the level of preexisting neutralizing antibody at infection, not age, was the most important factor influencing this response. RSV can induce substantial neutralizing antibody responses in young infants when the titer of preexisting antibodies is low.The Journal of Infectious Diseases 11/2008; 198(7):1007-15. · 6.41 Impact Factor -
Article: Indirect effect of 7-valent pneumococcal conjugate vaccine on pneumococcal colonization among unvaccinated household members.
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ABSTRACT: Since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7) in the United States, rates of invasive pneumococcal disease have decreased in both vaccinated and unvaccinated age groups. Reduction of invasive pneumococcal disease in unvaccinated groups has been attributed to reduced transmission of vaccine-type pneumococci in the community. Understanding the impact of PCV7 on carriage among vaccinated and unvaccinated community members is critical to interpreting, predicting, and understanding the impact of PCV7 on disease. A group-randomized, phase III efficacy trial of PCV7 was conducted among southwestern American Indian communities. Meningococcal conjugate vaccine against serogroup C was used as the control. After the trial was unblinded, we conducted a carriage study of participating communities to evaluate the impact of PCV7 on colonization among trial participants and their unvaccinated household members. Adults and unvaccinated children aged <5 years living in households with a PCV7 vaccinee were less likely to be colonized with vaccine-type pneumococci (odds ratio [OR] for adults, 0.57; 95% confidence interval [CI], 0.33-0.99; OR for children, 0.57; 95% CI, 0.26-0.98) than were those living in a household with a control vaccinee. There was no difference for children aged 5-17 years. Decreases in vaccine-type carriage were offset by increases in carriage of nonvaccine types. Among adults living with a trial participant colonized with vaccine-type pneumococcus, those in the households randomized to receive PCV7 were less likely to be colonized with the same serotype than were those in the households randomized to receive the control vaccine (OR, 0.34; 95% CI, 0.11-0.99). Vaccine-type pneumococcal carriage was lower among adults and unvaccinated children living with a PCV7 vaccinee. This is attributable to reduced exposure and reduced transmission when exposure occurs.Clinical Infectious Diseases 09/2008; 47(8):989-96. · 9.15 Impact Factor -
Article: Depressive symptoms among reservation-based pregnant American Indian adolescents.
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ABSTRACT: To examine rates and correlates of depressive symptoms among pregnant reservation-based American Indian (AI) adolescents from the Southwestern United States (N = 53). Data were derived from a study evaluating a home-visiting program designed to promote positive parenting among young families. Participants included a volunteer, convenience sample of expectant mothers who completed behavioral and mental health self-report questionnaires. Depressive symptoms were assessed using the Center for Epidemiological Studies-Depression scale (CES-D). Three risk domains were analyzed in relation to depressive symptoms: sociodemographics, family relations, and psychosocial functioning. Forty-seven percent of expectant mothers scored at or above the widely accepted clinical cutoff score of 16 on the CES-D; 30% scored at or above 20, a score more likely to reflect elevated depressive symptoms among adolescents; and almost 20% scored at or above 28 (one standard deviation above the mean), a score suggestive of clinical depression. Higher levels of depressive symptoms were associated with less use of public assistance, external locus of control, less social support, and lower self-esteem. Data suggest that a large proportion of pregnant AI adolescents reported elevated depressive symptoms, though rates are similar to non-pregnant AI adolescent samples.Maternal and Child Health Journal 06/2008; 12 Suppl 1:110-8. · 2.24 Impact Factor -
Article: Invasive pneumococcal disease among White Mountain Apache adults, 1991-2005.
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ABSTRACT: Certain Native American populations have high rates of invasive pneumococcal disease (IPD). We aimed to determine the disease spectrum and risk factors of White Mountain Apache adults (age, >or=18 years) with IPD and the use and effectiveness of pneumococcal polysaccharide vaccine (PPV) in this population. We conducted active surveillance for IPD between 1991 and 2005. Medical records were reviewed, and isolates were serotyped. Vaccine use was assessed in 2004-2005 among White Mountain Apache adults with an indication for pneumococcal vaccination. The effectiveness of PPV was determined through an indirect cohort method. Among the 115 IPD cases (in 109 persons), the mean age was 43 years; 62% were male; 91% had risk factors, and alcoholism predominated (73%). Alcoholic patients were younger (mean age, 40.1 years; P<.001) and more often male (70%; P=.001) compared with nonalcoholic patients. The case fatality rate was 15%; all deaths occurred among those with risk factors. Only age 65 years or older was associated with increased risk of death. Of 447 White Mountain Apache persons at high risk, 76% had received PPV. Vaccination rates were highest among subjects with pulmonary disease (95%) and diabetes (89%) and lowest among those aged 50 to 64 years (40%). Of the 115 IPD cases for which serotypes were available, 77% were due to serotypes contained in PPV. The effectiveness of PPV against serotype-specific IPD, as measured by the indirect cohort analysis of IPD cases, was 68% (95% confidence interval, 3%-90%). Among White Mountain Apache adults with IPD, alcoholism is common and contributes to the younger age and male predominance of cases. Pneumococcal vaccination rates are high, and there is suggestive evidence of the effectiveness of PPV in this population. Additional preventive strategies, including risk factor modification and vaccination of younger high-risk adults, should be pursued.Archives of Internal Medicine 05/2008; 168(7):749-55. · 11.46 Impact Factor
Top co-authors
Top Journals
Institutions
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2003–2013
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Johns Hopkins Bloomberg School of Public Health
Baltimore, MD, USA
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2010
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Johns Hopkins Medicine
- Department of International Health
Baltimore, MD, USA
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2007–2010
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Johns Hopkins University
- Department of International Health
Baltimore, MD, USA -
Harvard University
- Department of Epidemiology
Cambridge, MA, USA
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2003–2004
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Centers for Disease Control and Prevention
- Division of Bacterial Diseases
Druid Hills, GA, USA
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