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BACKGROUND: Avian influenza viruses pose significant risk to human health. Vaccines targeting the hemagglutinin of these viruses are poorly immunogenic without the use of adjuvants. METHODS: Twenty healthy men and women (18-49 years of age) were randomized to receive two doses of inactivated influenza A/H5N1 vaccine alone (IIV) or with AS03 adjuvant (IIV-AS03) one month apart. Urine and serum samples were collected on day 0 and on days 1, 3, and 7 following first vaccination and subjected to metabolomics analyses to identify metabolites, metabolic pathways, and metabolite clusters associated with immunization. RESULTS: Seventy-three differentially abundant (DA) serum and 88 urine metabolites were identified for any post-vaccination day comparison. Pathway analysis revealed enrichment of tryptophan, tyrosine and nicotinate metabolism in urine and serum among IIV-AS03 recipients. Increased urine abundance of 4-vinylphenol sulfate on Day 1 was associated with serologic response based on hemagglutination inhibition responses. In addition, 9 DA urine metabolites were identified in participants with malaise compared to those without. CONCLUSIONS: Our findings suggest that tryptophan, tyrosine, and nicotinate metabolism are upregulated among IIV-AS03 recipients compared with IIV alone. Metabolites within these pathways may serve as measures of immunogenicity and may provide mechanistic insights for adjuvanted vaccines.
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BACKGROUND: MF59-adjuvanted gB subunit (gB/MF59) vaccine demonstrated approximately 50% efficacy against human cytomegalovirus (HCMV) acquisition in multiple clinical trials, suggesting that efforts to improve this vaccine design might yield a vaccine suitable for licensure. METHODS: A messenger RNA (mRNA)-based vaccine candidate encoding HCMV gB and pentameric complex (PC), mRNA-1647, is currently in late-stage efficacy trials. However, its immunogenicity has not been compared to the partially effective gB/MF59 vaccine. We assessed neutralizing and Fc-mediated immunoglobulin G (IgG) effector antibody responses induced by mRNA-1647 in both HCMV-seropositive and -seronegative vaccinees from a first-in-human clinical trial through 1 year following third vaccination using a systems serology approach. Furthermore, we compared peak anti-gB antibody responses in seronegative mRNA-1647 vaccinees to that of seronegative gB/MF59 vaccine recipients. RESULTS: mRNA-1647 vaccination elicited and boosted HCMV-specific IgG responses in seronegative and seropositive vaccinees, respectively, including neutralizing and Fc-mediated effector antibody responses. gB-specific IgG responses were lower than PC-specific IgG responses. gB-specific IgG and antibody-dependent cellular phagocytosis responses were lower than those elicited by gB/MF59. However, mRNA-1647 elicited higher neutralization and antibody-dependent cellular cytotoxicity (ADCC) responses. CONCLUSIONS: Overall, mRNA-1647 vaccination induced polyfunctional and durable HCMV-specific antibody responses, with lower gB-specific IgG responses but higher neutralization and ADCC responses compared to the gB/MF59 vaccine. CLINICAL TRIALS REGISTRATION: NCT03382405 (mRNA-1647) and NCT00133497 (gB/MF59).
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Adjuvantes Imunológicos , Infecções por Citomegalovirus , Vacinas contra Citomegalovirus , Citomegalovirus , Polissorbatos , Esqualeno , Vacinas de mRNA , Humanos , Adjuvantes Imunológicos/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Citotoxicidade Celular Dependente de Anticorpos , Citomegalovirus/imunologia , Citomegalovirus/genética , Infecções por Citomegalovirus/prevenção & controle , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/virologia , Vacinas contra Citomegalovirus/administração & dosagem , Vacinas contra Citomegalovirus/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Vacinas de mRNA/administração & dosagem , Vacinas de mRNA/imunologia , Polissorbatos/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/imunologia , Esqualeno/administração & dosagem , Esqualeno/imunologia , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/genéticaRESUMO
BACKGROUND: The mechanisms by which cigarette smoking increases the risk of respiratory disease have been studied. However, less is known about risks of respiratory symptoms and outcomes associated with smoking cigars, and risks by cigar types have not been previously explored. The aim of this study was to examine associations between cigar use, including traditional cigars, cigarillos, filtered cigars, and dual cigar and cigarette use, and functionally important respiratory symptoms (FIRS), lifetime asthma diagnosis, uncontrolled asthma, and new cases of FIRS. METHODS: Data from Waves 2-5 (2014-19) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative longitudinal study, were analyzed in two ways. For cross-sectional analysis, the analytic sample included adults 18 and older at each wave, resulting in 44,040 observations. Separately, longitudinal analyses were assessed among adults 18 and older at Wave 2, resulting in 7,930 individuals. Both analyses excluded adults with chronic obstructive pulmonary disease (COPD) or non-asthma respiratory disease. RESULTS: Current established cigarillo smokers had higher odds of having FIRS (Adjusted odds ratio (AOR): 1.72; 95% CI: 1.08, 2.74) compared to never smokers of cigarillos and cigarettes, after adjusting for covariates. Current established filtered cigar smokers had higher odds of asthma diagnosis (AOR: 1.35; 95% CI: 1.10, 1.66) while current established dual smokers of filtered cigars and cigarettes had higher odds of uncontrolled asthma (AOR: 5.13; 95% CI: 1.75, 15.02) compared to never smokers of filtered cigars or cigarettes. Both current established cigar smokers and current established dual smokers of cigarettes and cigars had higher odds of new FIRS compared to never cigar or cigarette smokers (AORs: 1.62; 95% CI: 1.02, 2.60 for exclusive cigars and 2.55; 95% CI 1.57, 4.14 for dual smokers). CONCLUSIONS: This study provides evidence that cigar smokers or dual smokers of cigars and cigarettes have greater odds of FIRS, asthma, and uncontrolled asthma and that new incidence of FIRS is higher among any cigar smokers compared to never cigar or cigarette smokers. Understanding health impacts associated with cigar use provides information for supporting policy development, as well as for designing clinical interventions focused on smoking cessation for cigars.
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Fumar Charutos , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Estudos Longitudinais , Estudos Transversais , Adulto Jovem , Adolescente , Idoso , Fumar Charutos/epidemiologia , Asma/epidemiologia , Asma/diagnóstico , Fumantes , Produtos do Tabaco/efeitos adversos , Estados Unidos/epidemiologia , Fatores de RiscoRESUMO
OBJECTIVE: This study measured anatalline and nicotelline, two minor tobacco alkaloids, to discriminate between exclusive smokeless tobacco (SLT) use, exclusive electronic nicotine delivery systems (ENDS) use, exclusive cigarette use, dual SLT and cigarette use, and dual ENDS and cigarette use. METHODS: N = 664 urine samples from participants in the Population Assessment of Tobacco and Health Study were analyzed for anatalline and nicotelline. Geometric means and 95% confidence intervals were calculated for biomarker levels and their ratios. Non-parametric Receiver Operating Characteristic analyses were used to determine optimal cut-points of natural log-transformed biomarker ratios for distinguishing between tobacco use groups. RESULTS: The anatalline/nicotelline ratio distinguished exclusive cigarette from exclusive SLT use (threshold = 18.1, sensitivity = 89.3%, specificity = 86.4%, AUC = 0.90), and exclusive SLT from exclusive ENDS use (threshold = 12.8, sensitivity = 96.4%, specificity = 76.3%, AUC = 0.90) very well, but had reduced sensitivity and specificity when distinguishing exclusive cigarette from exclusive ENDS or any dual use with cigarettes. CONCLUSIONS: This research fills a gap in understanding the public health consequences of SLT and ENDS use by providing objective measures that can signal use of these products alone or in combination with cigarettes.
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INTRODUCTION: We compare real-world trends in population-level cigarette discontinuation rates among adults (ages ≥21) who smoked cigarettes, by electronic nicotine delivery systems (ENDS) use. AIMS AND METHODS: U.S nationally representative data from adults in the Population Assessment of Tobacco and Health (PATH) Study (2013/14-2021, Waves 1-6) who smoked cigarettes in the past 30 days (P30D) were analyzed (nâ =â 13 640). The exposure was P30D ENDS use. The outcome was P30D cigarette discontinuation at biennial follow-up. Weighted trend analyses were conducted to test for differences in cigarette discontinuation trends by ENDS use. RESULTS: Between 2013/14 and 2015/16, cigarette discontinuation rates were both 16% for those who used ENDS and for those who did not; between 2018/19 and 2021, rates were ~30% for those who used ENDS and ~20% for those who did not; the time by ENDS use interaction was significant. CONCLUSIONS: The relationship between adults' ENDS use and cigarette discontinuation in the context of an expanded ENDS marketplace, new tobacco regulatory actions, and COVID-19 differs from the relationship in earlier years. IMPLICATIONS: It is important for public health decisions to be informed by research based on the contemporary ENDS marketplace and circumstances.
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Pertussis (whooping cough) is a reemergent, highly contagious respiratory infection of public health concern. Infants prior to initiation of their primary vaccination series are the most vulnerable to severe infection, and even death. Vaccination during pregnancy is an efficacious means of reducing infection in infants. This approach relies on boosting maternal immunity and passive transfer of antibodies to the infant via placenta and breast milk. Similarly, maternal vaccination post-partum can enhance maternal-infant immunity. To support the analysis of pertussis immunity in the context of maternal-infant immunization, we developed a high throughput multiplex assay for simultaneous quantification of serum IgG antibodies against pertussis vaccine antigens: pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM2/3), and against tetanus (TT) and diphtheria toxoids (DT), using the Meso Scale Discovery (MSD) platform. The assay was qualified, and specificity, sensitivity, accuracy, precision, linearity, and robustness were demonstrated. The assay was subsequently adapted for quantification of IgG and IgA in breast milk. Applied to a serological survey of pregnant women living in the United States and sub-Saharan Africa, this method revealed differences in magnitude and breadth of antibody profile, consistent with history of vaccination. A longitudinal analysis of Tdap responses in women vaccinated post-partum demonstrated a rapid increase in serum IgG that remained elevated for up to 24 months. Likewise, high levels of vaccine-specific IgA and IgG antibodies were present in breast milk, although they exhibited faster decay. This multiplex MSD assay is a reliable and practical tool for quantification of pertussis, tetanus, and diphtheria antibodies in serum and breast milk in serosurveys or vaccine studies. IMPORTANCE: Pertussis (whooping cough) has reemerged in recent years. Vaccination during pregnancy is an effective approach to prevent illness during the first months of life. We developed a multiplex assay for quantification of pertussis, tetanus, and diphtheria serum antibodies using the Meso Scale Discovery (MSD) platform; the method was qualified, and specificity, precision, accuracy, linearity, and limits of quantification were defined. It was also adapted for quantification of antibodies in breast milk. We successfully determined serostatus in women from different regions and with different vaccination histories, as well as responses to Tdap in blood and breast milk post-partum. This is the first description of a multiplex assay for the quantification of pertussis, tetanus, and diphtheria antibodies in breast milk.
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Anticorpos Antibacterianos , Vacinas contra Difteria, Tétano e Coqueluche Acelular , Imunoglobulina G , Leite Humano , Coqueluche , Humanos , Feminino , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Leite Humano/imunologia , Coqueluche/prevenção & controle , Coqueluche/imunologia , Imunoglobulina G/sangue , Vacinas contra Difteria, Tétano e Coqueluche Acelular/imunologia , Gravidez , Adulto , Difteria/prevenção & controle , Difteria/imunologia , Tétano/prevenção & controle , Tétano/imunologia , Adulto Jovem , Vacinação , Imunidade Materno-Adquirida/imunologiaRESUMO
The intestinal microbiome influences growth and disease progression in children with cystic fibrosis (CF). Elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA), the newest pharmaceutical modulator for CF, restores the function of the pathogenic mutated CF transmembrane conductance regulator (CFTR) channel. We performed a single-center longitudinal analysis of the effect of ELX/TEZ/IVA on the intestinal microbiome, intestinal inflammation, and clinical parameters in children with CF. Following ELX/TEZ/IVA, children with CF had significant improvements in body mass index and percent predicted forced expiratory volume in one second, and required fewer antibiotics for respiratory infections. Intestinal microbiome diversity increased following ELX/TEZ/IVA coupled with a decrease in the intestinal carriage of Staphylococcus aureus, the predominant respiratory pathogen in children with CF. There was a reduced abundance of microbiome-encoded antibiotic resistance genes. Microbial pathways for aerobic respiration were reduced after ELX/TEZ/IVA. The abundance of microbial acid tolerance genes was reduced, indicating microbial adaptation to increased CFTR function. In all, this study represents the first comprehensive analysis of the intestinal microbiome in children with CF receiving ELX/TEZ/IVA.IMPORTANCECystic fibrosis (CF) is an autosomal recessive disease with significant gastrointestinal symptoms in addition to pulmonary complications. Recently approved treatments for CF, CF transmembrane conductance regulator (CFTR) modulators, are anticipated to substantially improve the care of people with CF and extend their lifespans. Prior work has shown that the intestinal microbiome correlates with health outcomes in CF, particularly in children. Here, we study the intestinal microbiome of children with CF before and after the CFTR modulator, ELX/TEZ/IVA. We identify promising improvements in microbiome diversity, reduced measures of intestinal inflammation, and reduced antibiotic resistance genes. We present specific bacterial taxa and protein groups which change following ELX/TEZ/IVA. These results will inform future mechanistic studies to understand the microbial improvements associated with CFTR modulator treatment. This study demonstrates how the microbiome can change in response to a targeted medication that corrects a genetic disease.
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Aminofenóis , Benzodioxóis , Fibrose Cística , Microbioma Gastrointestinal , Indóis , Pirazóis , Piridinas , Pirrolidinas , Quinolonas , Criança , Humanos , Fibrose Cística/tratamento farmacológico , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Antibacterianos/uso terapêutico , Inflamação , MutaçãoRESUMO
As the world's population grows older, vaccination is becoming a key strategy for promoting healthy aging. Despite scientific progress in adult vaccine development, obstacles such as immunosenescence and vaccine hesitancy remain. To unlock the potential of adult vaccines fully, we must enhance immunization programs, dispel misinformation, and invest in research that deepens our understanding of aging and immunity.
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Envelhecimento Saudável , Vacinação , Humanos , Envelhecimento/imunologia , Vacinas/imunologiaRESUMO
Introduction: The study assessed longitudinal transitions among adult (18 and older) past 30-day daily and non-daily dual users of cigarettes and electronic nicotine delivery systems (ENDS). Methods: Using data from Wave 4 (W4; 2016/17) and Wave 5 (W5; 2018/19) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal cohort study of US adults, multivariable regressions were conducted among W4 dual users of cigarettes and ENDS to examine past 30-day cigarette smoking at W5. The study also analyzed changes in frequency of past 30-day smoking and cigarettes smoked per day between W4 and W5, stratified by W4/W5 daily/non-daily ENDS use among W4 daily and non-daily cigarette smokers. Results: Among W4 dual users, those smoking daily and using ENDS non-daily had higher odds of daily cigarette smoking at W5 than daily users of both products (AOR: 2.32, 95 % CI: 1.38-3.90). W4 daily smokers who used ENDS daily at Wave 5 smoked cigarettes on fewer days at Wave 5 than W4 daily smokers who were either daily ENDS users at Wave 4 (B = -4.59; SE = 1.43, p < 0.01) or non-daily ENDS users at Wave 4 (B = -4.55; SE = 1.24, p < 0.001). Among W4 non-daily cigarette smokers, W4 non-daily ENDS users who used daily at W5 smoked cigarettes on fewer days (B = -4.04, SE = 1.82) at W5 than those who were non-daily ENDS users at W4 and W5. Conclusions: Findings highlight the importance of frequency of ENDS use in reducing cigarette smoking and could inform smoking cessation interventions among daily cigarette smokers.
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This study examined associations between established cigar use and prevalence and incidence of cardiovascular diseases (CVD; congestive heart failure, stroke, or heart attack/needed bypass surgery) among U.S. adults, 40 years or older. Using Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study, incidence (Nindividuals (Nind) = 6,692; Nobservations (Nobs) = 23,738) and prevalence (Nind = 7,819; Nobs = 33,952) of CVD outcomes were examined using weighted generalized estimating equations (WGEEs) among adults who were exclusive current/former established cigar smokers (ever cigar smokers who have smoked fairly regularly), exclusive current/former established cigarette smokers (lifetime smokers of 100 or more cigarettes), dual current/former established cigarette and cigar smokers compared with never smokers of cigars or cigarettes, adjusting for covariates. The population-averaged incidence of CVD from one wave to next among exclusive current/former established cigar smokers during a six-year period based on WGEEs was low (overall average rate of 3.0 %; 95 % CI: 1.2, 7.0). Compared with never users, exclusive current/former established cigar smokers (OR = 1.67, 95 % CI: 1.11, 2.51) and exclusive current/former established cigarette smokers (OR = 2.12, 95 % CI: 1.45, 3.09) were more likely to have any CVD outcome in unadjusted analyses. When adjusted for covariates, only exclusive current/former established cigarette use was associated with CVD outcomes (AOR = 1.60, CI: 1.07, 2.40). Results suggest that exclusive established use of cigars or duration of exclusive cigar use was not associated with lifetime CVD prevalence compared with never cigar or cigarette smokers, which is important in understanding health outcomes in cigar users.
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Introduction: We examined the association between tobacco product use and health-related quality of life (HRQoL) among individuals with chronic obstructive pulmonary disease (COPD) in Waves 1-5 of the Population Assessment of Tobacco and Health (PATH) Study. Methods: Adults ≥40 years with an ever COPD diagnosis were included in cross-sectional (Wave 5) and longitudinal (Waves 1 to 5) analyses. Tobacco use included 13 mutually exclusive categories of past 30-day (P30D) single use and polyuse with P30D exclusive cigarette use and ≥5-year cigarette cessation as reference groups. Multivariable linear regression and generalized estimating equations (GEE) were used to examine the association between tobacco use and HRQoL as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) Global-10 questionnaire. Results: Of 1670 adults, 79.4% ever used cigarettes; mean (standard error [SE]) pack years was 30.9 (1.1). In cross-sectional analysis, P30D exclusive cigarette use, and e-cigarette/cigarette dual use were associated with worse HRQoL compared to ≥5-year cigarette cessation. Compared to P30D exclusive cigarette use, never tobacco use and ≥5-year cigarette cessation were associated with better HRQoL, while e-cigarette/cigarette dual use had worse HRQoL. Longitudinally (n=686), e-cigarette/cigarette dual use was associated with worsening HRQoL compared to both reference groups. Only never tobacco use was associated with higher HRQoL over time compared to P30D exclusive cigarette use. Conclusions: E-cigarette/cigarette dual use was associated with worse HRQoL compared to ≥5-year cigarette cessation and exclusive cigarette use. Never use and ≥5-year cigarette cessation were the only categories associated with higher HRQoL compared to exclusive cigarette use. Findings highlight the importance of complete smoking cessation for individuals with COPD.
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The U.S. COVID-19 vaccination program, which commenced in December 2020, has been instrumental in preventing morbidity and mortality from COVID-19 disease. Safety monitoring has been an essential component of the program. The federal government undertook a comprehensive and coordinated approach to implement complementary safety monitoring systems and to communicate findings in a timely and transparent way to healthcare providers, policymakers, and the public. Monitoring involved both well-established and newly developed systems that relied on both spontaneous (passive) and active surveillance methods. Clinical consultation for individual cases of adverse events following vaccination was performed, and monitoring of special populations, such as pregnant persons, was conducted. This report describes the U.S. government's COVID-19 vaccine safety monitoring systems and programs used by the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the Department of Defense, the Department of Veterans Affairs, and the Indian Health Service. Using the adverse event of myocarditis following mRNA COVID-19 vaccination as a model, we demonstrate how the multiple, complementary monitoring systems worked to rapidly detect, assess, and verify a vaccine safety signal. In addition, longer-term follow-up was conducted to evaluate the recovery status of myocarditis cases following vaccination. Finally, the process for timely and transparent communication and dissemination of COVID-19 vaccine safety data is described, highlighting the responsiveness and robustness of the U.S. vaccine safety monitoring infrastructure during the national COVID-19 vaccination program.
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During the COVID-19 pandemic, candidate COVID-19 vaccines were being developed for potential use in the United States on an unprecedented, accelerated schedule. It was anticipated that once available, under U.S. Food and Drug Administration (FDA) Emergency Use Authorization (EUA) or FDA approval, COVID-19 vaccines would be broadly used and potentially administered to millions of individuals in a short period of time. Intensive monitoring in the post-EUA/licensure period would be necessary for timely detection and assessment of potential safety concerns. To address this, the Centers for Disease Control and Prevention (CDC) convened an Advisory Committee on Immunization Practices (ACIP) work group focused solely on COVID-19 vaccine safety, consisting of independent vaccine safety experts and representatives from federal agencies - the ACIP COVID-19 Vaccine Safety Technical Work Group (VaST). This report provides an overview of the organization and activities of VaST, summarizes data reviewed as part of the comprehensive effort to monitor vaccine safety during the COVID-19 pandemic, and highlights selected actions taken by CDC, ACIP, and FDA in response to accumulating post-authorization safety data. VaST convened regular meetings over the course of 29 months, from November 2020 through April 2023; through March 2023 FDA issued EUAs for six COVID-19 vaccines from four different manufacturers and subsequently licensed two of these COVID-19 vaccines. The independent vaccine safety experts collaborated with federal agencies to ensure timely assessment of vaccine safety data during this time. VaST worked closely with the ACIP COVID-19 Vaccines Work Group; that work group used safety data and VaST's assessments for benefit-risk assessments and guidance for COVID-19 vaccination policy. Safety topics reviewed by VaST included those identified in safety monitoring systems and other topics of scientific or public interest. VaST provided guidance to CDC's COVID-19 vaccine safety monitoring efforts, provided a forum for review of data from several U.S. government vaccine safety systems, and assured that a diverse group of scientists and clinicians, external to the federal government, promptly reviewed vaccine safety data. In the event of a future pandemic or other biological public health emergency, the VaST model could be used to strengthen vaccine safety monitoring, enhance public confidence, and increase transparency through incorporation of independent, non-government safety experts into the monitoring process, and through strong collaboration among federal and other partners.
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The impact of SARS-CoV-2 infections in children has fortunately been lower than what has been seen in adults. However, even previously healthy children have developed severe disease, sometimes with subsequent mortality, and those who are infants or adolescents, are from racial and ethnic minority groups, or have certain chronic conditions are at higher risk of these outcomes. During the pandemic, extensive studies of therapeutic agents, including antivirals and immunomodulators, were conducted in adults. Few trials included children, and most were in older children and adolescents. Thus, the potential benefits of therapies in children must be extrapolated from adult evidence. Despite these limitations, advisory committees of the National Institute of Health (NIH), the Infectious Disease Society of America (IDSA), and the Pediatric Infectious Diseases Society (PIDS) were constituted, and expert consensus guidelines were developed. This review provides a synthesis of those comprehensive recommendations for therapy in children. These address treatment during the early infectious period with antiviral agents, including remdesivir and nirmatrelvir/ritonavir, as well as treatment in the later period of immune dysregulation with corticosteroids and immunomodulators. In addition, the therapeutic approach for multisystem inflammatory syndrome in children (MIS-C), also referred to as Pediatric Inflammatory Multisystem Syndrome temporally associated with SARS-CoV-2 (PIMS-TS), is also provided.
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El objetivo del estudio fue determinar el porcentaje de colonización orofaríngea de Haemophilus influenzae tipo b (Hib) y no tipificable (HiNT) en niños, cuidados en guardería y en hogar vacunados o no con PRP/T. Se incluyeron niños sanos, menores de 7 años, excluyendo aquellos con antibióticoterapia el mes previo a la inclusión, divididos en: Grupo I vacunados y Grupo II no vacunados, subdivididos según cuidados en hogar o guardería. Se obtuvieron hisopados orofaríngeos para cultivo, identificación y serotipificación de Hi (Phadebact Test); como medidas estadísticas se utilizaron Chi cuadrado, test de Fisher's y Z y el "odds ratio". Se incluyeron 320 niños, 99 del Grupo I (49 en hogar y 50 en guarderías) y 221 en Grupo II (94 y 127, respectivamente). El porcentaje de portadores fue 22,8 (17,8 por ciento HiNT y 5 por ciento Hib). En el grupo I sólo se identificó HiNT y en el grupo II, de 56 cepas, 16 fueron Hib (p = 0,016). Predominó el Hib en guarderias (odds ratio = 13,5). La colonización por HiNT fue similar en ambos grupos, cuidados en el hogar (18 vs 19 por ciento) y en guarderías (16 vs 17 por ciento). En el grupo II la colonización por Hib fue mayor en guarderías (12 por ciento) que en el hogar (1 por ciento) (p = 0,002). En conclusión, el porcentaje de colonización por Hib en la muestra total y en no vacunados del hogar fue semejante a países desarrollados en la era prevacuna. La ausencia de la vacuna PRP-T y la asistencia a guarderías son factores de riesgo para colonización por Hib