Safety and Immunogenicity of a ChAd155-Vectored Respiratory Syncytial Virus Vaccine in Infants 6-7 Months of age: A Phase 1/2 Randomized Trial.

BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract infections in infants. This phase 1/2, observer-blind, randomized, controlled study assessed the safety and immunogenicity of an investigational chimpanzee-derived adenoviral vector RSV vaccine (ChAd155-RSV, expressing RSV F, N, and M2-1) in infants. METHODS: Healthy 6- to 7-month-olds were 1:1:1-randomized to receive 1 low ChAd155-RSV dose (1.5 × 1010 viral particles) followed by placebo (RSV_1D); 2 high ChAd155-RSV doses (5 × 1010 viral particles) (RSV_2D); or active comparator vaccines/placebo (comparator) on days 1 and 31. Follow-up lasted approximately 2 years. RESULTS: Two hundred one infants were vaccinated (RSV_1D: 65; RSV_2D: 71; comparator: 65); 159 were RSV-seronaive at baseline. Most solicited and unsolicited adverse events after ChAd155-RSV occurred at similar or lower rates than after active comparators. In infants who developed RSV infection, there was no evidence of vaccine-associated enhanced respiratory disease (VAERD). RSV-A neutralizing titers and RSV F-binding antibody concentrations were higher post-ChAd155-RSV than postcomparator at days 31, 61, and end of RSV season 1 (mean follow-up, 7 months). High-dose ChAd155-RSV induced stronger responses than low-dose, with further increases post-dose 2. CONCLUSIONS: ChAd155-RSV administered to 6- to 7-month-olds had a reactogenicity/safety profile like other childhood vaccines, showed no evidence of VAERD, and induced a humoral immune response. Clinical Trials Registration. NCT03636906.

A 20-year retrospective study of osteoarticular tuberculosis in a pediatric third level referral center.

PURPOSE: The objective of the present study is to describe the clinical, diagnostic, radiological and therapeutic aspects of osteoarticular tuberculosis (OATB) in patients in a tertiary pediatric hospital, to know if the diagnosis of OATB in pediatrics is a challenge due to its insidious clinical presentation. METHODS: A retrospective, descriptive study of the cases of Tuberculosis (TB) in children was carried out. A total of 159 cases met the condition for the analysis. RESULTS: The most frequent TB modality was extrapulmonary in 85%. Out of this, only 29% was OATB. The mean age was 4.9 years (range 8 months-16 years). Eighty-six per cent of cases received Bacille Calmette-Guérin (BCG) vaccination at birth. Median time of symptoms prior to diagnosis was 8 months. Microbiological confirmation was achieved only in five cases, with a high sensitivity to the antimicrobial treatment. Mycobacterium bovis BCG strain Tokio 172 was confirmed in three cases. Mortality rate was 0% during the time of study CONCLUSION: Our study describes the epidemiological characteristics of OATB cases in Mexican children. This data revealed a high prevalence of bone and joint TB infection. Pediatric OATB should be considered in cases with lytic bone lesions, fever and local pain. In countries with BCG immunization program, M. bovis should not be forgotten as an etiological agent. The low detection rate with one technique approach highlights the urgent need for more sensitive test to diagnose OATB in children.

Clinical and Epidemiological Characteristics of Paediatric Patients Diagnosed with COVID-19 in a Tertiary Hospital in Mexico City.

COVID-19 affects the paediatric population less frequently than adults. A retrospective study was performed in a tertiary paediatric hospital in Mexico City in children <18 years of age who were hospitalized with a positive reverse transcription-polymerase chain reaction for SARS-CoV-2. Included in the study were 86 patients with a median age of 10 years old (IQR 2.6-14.3 years), who were classified in three groups: previously healthy, with chronic disease and immunosuppressed patients. The principal signs and symptoms were fever (81%), cough (51%) and headache (35%). A total of 20 patients (23%) required management in the paediatric intensive care unit (PICU) and 17% needed mechanical ventilation for an average of 12.7 days (IQR 2-29 days). There was no statistically significant difference between the three clinical classification groups in those patients admitted to the PICU, most of which were previously healthy patients. The mortality rate was 5% (four patients). Given that the paediatric population is susceptible to infection, potential transmitters and to clinical presentations with variable degrees of severity, it is important to continue reinforcing social distancing measures.

Immunogenicity and safety of a tetravalent dengue vaccine in dengue-naïve adolescents in Mexico City.

OBJECTIVE: To describe the immunogenicity and safety of a tetravalent dengue vaccine (TAK-003) in healthy adolescents living in Mexico City, an area considered non-endemic for dengue (NCT03341637). METHODS: Participants aged 12-17 years were randomized 3:1 to receive two doses (Month 0 and Month 3) of TAK-003 or placebo. Immunogenicity was assessed by microneutralization assay of dengue neutralizing antibodies at baseline, Months 4 and 9. Solicited and unsolicited adverse events (AEs) were recorded after each vaccination. Serious (SAEs) and medically-attended AEs (MAAEs) were recorded throughout the study. RESULTS: 400 adolescents were enrolled, 391 (97.8%) completed the study. Thirty-six (9%) were baseline seropositive to ≥1 serotypes (reciprocal titer ≥10). Geometric mean titers (GMTs) in baseline seronegative TAK-003 recipients were 328, 1743, 120, and 143 at Month 4, and 135, 741, 46, and 38 at Month 9 against DENV-1, -2, -3, and -4, respectively. Placebo GMTs remained <10. Tetravalent seropositivity rates in vaccine recipients were 99.6% and 85.8% at Months 4 and 9, respectively. One MAAE in each group was considered treatment-related (TAK-003: injection-site erythema, and placebo: pharyngitis). CONCLUSION: TAK-003 was immunogenic against all four serotypes and was well tolerated in dengue-naïve adolescents living in Mexico City.

Universal influenza vaccination: a Mexican Expert Position Paper.

OBJECTIVE: Influenza is a costly disease for the population. It is a cause of seasonal morbidity and mortality, epidemics and pandemics or syndemics. Given the variability of the virus, surveillance systems are implemented in order to update the strains and include them in the annual influenza vaccine. This vaccine is currently recommended in some high-risk groups. However, universal vaccination remains controversial. To evaluate the evidence and describe the position of a panel of experts on the relevance of universal vaccination against influenza virus. MATERIAL AND METHODS: Five clinical questions were asked, whereby a systematic search of the literature in electronic sources and a Delphi panel were carried out. The evidence was analyzed, and recommendations were issued by the experts. RESULTS: The group of experts recommends vaccinating the population starting at six months of age and include people who live with egg protein allergy, with comorbidities (diabetes, obesity, cancer), health workers and pregnant women. CONCLUSIONS: Vaccination, starting with vulnerable groups, is a necessary, ethical and cost-effective strategy. However, expanding the coverage to achieve universal vaccination could reduce the transmission of the disease and its consequences in the population.

OBJETIVO: La influenza es una enfermedad costosa para la población. Es causa de morbimortalidad estacional, epidemias y pandemias o sindemias. Debido a la variabilidad del virus, se implementan sistemas de vigilancia para actualizar las cepas e incluirlas en la vacuna antiinfluenza anual. Actualmente se recomienda esta vacuna en algunos grupos de alto riesgo. Sin embargo, la vacunación universal es aún controvertida. Evaluar la evidencia y describir la posición de un panel de expertos sobre la pertinencia de la vacunación universal contra el virus de influenza. MATERIAL Y MÉTODOS: Se realizaron cinco preguntas clínicas, con las que se realizó una búsqueda sistemática de la literatura en fuentes electrónicas y un panel Delphi. Se analizó la evidencia y se emitieron recomendaciones por los expertos. RESULTADOS: El grupo de expertos recomienda vacunar a la población desde los seis meses de edad e incluir a personas que viven con alergia a la proteína del huevo, con comorbilidades (diabetes, obesidad, cáncer), trabajadores de la salud y embarazadas. CONCLUSIONES: La vacunación, iniciando con los grupos vulnerables, es una estrategia necesaria, ética y costo-efectiva. Sin embargo, extender la cobertura para lograr la vacunación universal podría disminuir la transmisión de la enfermedad y sus consecuencias en la población.

Pulmonary tuberculous: Symptoms, diagnosis and treatment. 19-year experience in a third level pediatric hospital.

BACKGROUND: Pulmonary tuberculosis (PTB) is an infectious disease that involves the lungs and can be lethal in many cases. Tuberculosis (TB) in children represents 5 to 20% of the total TB cases. However, there are few updated information on pediatric TB, reason why the objective of the present study is to know the real situation of PTB in the population of children in terms of its diagnosis and treatment in a third level pediatric hospital. METHODS: A retrospective study based on a revision of clinical files of patients less than 18 years old diagnosed with PTB from January 1994 to January 2013 at Instituto Nacional de Pediatria, Mexico City was carried out. A probable diagnosis was based on 3 or more of the following: two or more weeks of cough, fever, tuberculin purified protein derivative (PPD) +, previous TB exposure, suggestive chest X-ray, and favorable response to treatment. Definitive diagnosis was based on positive acid-fast bacilli (AFB) or culture. RESULTS: In the 19-year period of revision, 87 children were diagnosed with PTB; 57 (65.5%) had bacteriologic confirmation with ZN staining or culture positive (in fact, 22 were ZN and culture positive), and 30 (34.5%) had a probable diagnosis; 14(16.1%) were diagnosed with concomitant disease, while 69/81 were immunized. Median evolution time was 21 days (5-150). Fever was found in 94.3%, cough in 77%, and weight loss in 55.2%. History of contact with TB was established in 41.9%. Chest X-ray showed consolidation in 48.3% and mediastinal lymph node in 47.1%. PPD was positive in 59.2%, while positive AFB was found in 51.7% cases. Culture was positive in 24/79 patients (30.4%), PCR in 20/27 (74.1%). 39 (44.8%) patients were treated with rifampin, isoniazid, and pyrazinamide while 6 (6.9%) received the former drugs plus streptomycin and 42 (48.3%) the former plus ethambutol. There were three deaths. CONCLUSIONS: PTB in pediatric population represents a diagnostic challenge for the fact that clinical manifestations are unspecific and the diagnosis is not confirmed in all cases; that is why clinical suspicion, X-ray findings and PPD are indispensable for opportune start of treatment.

Immunogenicity of RV1 and RV5 vaccines administered in standard and interchangeable mixed schedules: a randomized, double-blind, non-inferiority clinical trial in Mexican infants.

Introduction: Rotavirus-associated diarrheal diseases significantly burden healthcare systems, particularly affecting infants under five years. Both Rotarix™ (RV1) and RotaTeq™ (RV5) vaccines have been effective but have distinct application schedules and limited interchangeability data. This study aims to provide evidence on the immunogenicity, reactogenicity, and safety of mixed RV1-RV5 schedules compared to their standard counterparts. Methods: This randomized, double-blind study evaluated the non-inferiority in terms of immunogenicity of mixed rotavirus vaccine schedules compared to standard RV1 and RV5 schedules in a cohort of 1,498 healthy infants aged 6 to 10 weeks. Participants were randomly assigned to one of seven groups receiving various combinations of RV1, and RV5. Standard RV1 and RV5 schedules served as controls of immunogenicity, reactogenicity, and safety analysis. IgA antibody levels were measured from blood samples collected before the first dose and one month after the third dose. Non-inferiority was concluded if the reduction in seroresponse rate in the mixed schemes, compared to the standard highest responding scheme, did not exceed the non-inferiority margin of -0.10. Reactogenicity traits and adverse events were monitored for 30 days after each vaccination and analyzed on the entire cohort. Results: Out of the initial cohort, 1,365 infants completed the study. Immunogenicity analysis included 1,014 infants, considering IgA antibody titers ≥20 U/mL as seropositive. Mixed vaccine schedules demonstrated non-inferiority to standard schedules, with no significant differences in immunogenic response. Safety profiles were comparable across all groups, with no increased incidence of serious adverse events or intussusception. Conclusion: The study confirms that mixed rotavirus vaccine schedules are non-inferior to standard RV1 and RV5 regimens in terms of immunogenicity and safety. This finding supports the flexibility of rotavirus vaccination strategies, particularly in contexts of vaccine shortage or logistic constraints. These results contribute to the global effort to optimize rotavirus vaccination programs for broader and more effective pediatric coverage.Clinical trial registration: ClinicalTrials.gov, NCT02193061.

A multi-country study of intussusception in children under 2 years of age in Latin America: analysis of prospective surveillance data.

BACKGROUND: Intussusception (IS) is a form of acute intestinal obstruction that occurs mainly in infants and is usually of unknown cause. An association between IS and the first licensed rotavirus vaccine, a reassortant-tetravalent, rhesus-based rotavirus vaccine (RRV-TV), led to the withdrawal of the vaccine. New rotavirus vaccines have now been developed and extensively studied for their potential association with IS. This study aimed to describe the epidemiology and to estimate the incidence of IS in Latin American infants prior to new vaccine introduction. METHODS: Children under 2 years of age representing potential IS cases were enrolled in 16 centers in 11 Latin American countries from January 2003 to May 2005. IS cases were classified as definite, probable, possible or suspected as stated on the Brighton Collaboration Working Group guidelines. RESULTS: From 517 potential cases identified, 476 (92%) cases were classified as definite, 21 probable, 10 possible and 10 suspected for intussusception. Among the 476 definite IS cases, the median age at presentation was 6.4 months with 89% of cases aged <1 year. The male to female ratio was 1.5:1. The incidence of definite IS per 100,000 subject-years ranged from 1.9 in Brazil to 62.4 in Argentina for children <2 years of age, and from 3.8 in Brazil to 105.3 in Argentina for children aged <1 year. Median hospital stay was 4 days with a high prevalence of surgery as the primary treatment (65%). Most cases (88%) made a complete recovery, but 13 (3%) died. No clear seasonal pattern of IS cases emerged. CONCLUSIONS: This study describes the epidemiology and estimates the incidence of IS in Latin American infants prior to the introduction of new rotavirus vaccines. The incidence of IS was found to vary between different countries, as observed in previous studies. TRIAL REGISTRATION: Clinical study identifier 999910/204 (SERO-EPI-IS-204).

Factors Associated with the Duration of Breastfeeding: The Practices of Mexican Mothers in a Megacity and in the Agricultural Town.

BACKGROUND: Breast milk is irreplaceable for healthy development. In Mexico, by 2019, the prevalence of exclusive breastfeeding (EBF) was low and the use of breastmilk substitutes (BMSs) was high. OBJECTIVE: The aim of this work was to evaluate the maternal and child characteristics related to breastfeeding (BF) duration and to the introduction of BMSs for residents of Mexico City (CdMX) and an agricultural town in Morelos. METHODS: A cross-sectional study was conducted with 160 mother-child binomials (0-15 months of age) from the megacity CdMX and the agricultural town. OUTCOMES: EBF and total breastfeeding (TBF) duration, age of transition to BMSs, and the introduction of complementary feeding (CF) were assessed. Associations with maternal and infant factors were assessed using Cox models. RESULTS: The prevalence of EBF in the joint samples at 5.9 months was 32.6% and 5.8% at 6 months. EBF was favored under the following conditions: living in CdMX, receiving prenatal care, no newborn hospitalization, and breastmilk provided as first food at birth. TBF was prolonged under the following conditions: older mother, female children, rooming-in care during puerperium, receiving BF upon discharge after birth, cohabiting with extended family, and having no siblings. The introduction of BMSs predominated under the following conditions: living in an agricultural town, BMSs given after birth before discharge, younger mother, worker mother, and lack of prenatal care. The early introduction of CF (before the fourth month) was 2% for CdMX and 14% for the agricultural town. CONCLUSIONS: The agricultural population had a higher risk of the premature interruption of EBF/TBF and the early introduction of BMSs and CF. Protective factors were family-friendly environments and being born in a baby-friendly hospital.

An expert panel opinion on protection against pertussis in Mexico: The role of acellular and whole-cell vaccines.

Pertussis is a highly contagious disease caused by Bordetella pertussis, which may be preventable by vaccination. There are two types of vaccines: whole-cell vaccines and acellular vaccines. Since pertussis control worldwide is heterogeneous, re-emergence of whooping cough has been observed in some countries. This re-emergence has been related to several factors: increased susceptibility to infection, better detection of disease, problems in obtaining adequate vaccination coverage, increase in susceptible subjects (mainly under 6 months of age), loss of immunity in adolescents and young adults, and likely genetic and adaptive B. pertussis changes. This paper discusses whole-cell and acellular vaccines' characteristics, advantages, and disadvantages. International recommendations are presented, and the participants' position is offered regarding the influence of the use of acellular vaccines and the potential disadvantages of reintroducing whole-cell vaccines, mainly due to their reactogenicity. Finally, strategies to achieve better control of pertussis in Mexico are discussed.

La tos ferina es una enfermedad causada por Bordetella pertussis. Aunque es altamente contagiosa, puede ser prevenible por vacunación. Existen dos tipos de vacunas: las de células enteras y las acelulares. La tos ferina ha resurgido en algunos países debido a que su control a escala mundial es heterogéneo. Esta reemergencia se ha relacionado con diversos factores: mayor sensibilidad hacia la infección, mejor detección de la enfermedad, problemas para obtener adecuadas coberturas de vacunación, incremento en los sujetos susceptibles (especialmente menores de 6 meses), pérdida de la inmunidad en los adolescentes y adultos jóvenes, y probables cambios genéticos y adaptativos de B. pertussis. En este documento se analizan las características, las ventajas y las desventajas de las vacunas de células enteras y de las vacunas acelulares. Se presentan las recomendaciones internacionales y se ofrece el posicionamiento de los participantes con respecto a la influencia del uso de vacunas acelulares y las desventajas potenciales de volver a utilizar vacunas de células enteras, en especial por su reactogenicidad. Por último, se analizan las estrategias para lograr un mejor control de la tos ferina en México.

[Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention. Expert Group on Pertussis Vaccination]. / Consenso para el diagnóstico clínico y microbiológico y la prevención de la infección por Bordetella pertussis. Grupo de expertos en vacunación contra tos ferina.

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.

Immunogenicity and Safety of a Measles-Mumps-Rubella Vaccine Administered as a First Dose to Children Aged 12 to 15 Months: A Phase III, Randomized, Noninferiority, Lot-to-Lot Consistency Study.

BACKGROUND: MMR II (M-M-R II [Merck & Co, Inc.]) is currently the only measles, mumps, and rubella (MMR) vaccine licensed in the United States. A second MMR vaccine would mitigate the potential risk of vaccine supply shortage or delay. In this study, we assessed the immunogenicity and safety of another MMR vaccine (MMR-RIT [Priorix, GlaxoSmithKline]) compared with those of the MMR II in 12- to 15-month-old children who received it as a first dose. METHODS: In this phase III, observer-blinded, noninferiority, lot-to-lot consistency clinical trial (ClinicalTrials.gov identifier NCT01702428), 5003 healthy children were randomly assigned to receive 1 dose of MMR-RIT (1 of 3 production lots) or MMR II along with other age-recommended routine vaccines. We evaluated the immunogenicity of all vaccines in terms of antibody concentrations (by using an enzyme-linked immunosorbent assay or electrochemiluminescence assay) and/or seroresponse rates 43 days after vaccination. We also assessed the reactogenicity and safety of the vaccines. RESULTS: Immunoresponses after vaccination with MMR-RIT were robust and noninferior to those after vaccination with the MMR II. Immunogenicity of the 3 production lots of MMR-RIT was consistent; more than 97% of the children had a seroresponse to MMR components. The coadministered vaccines elicited similar immunoresponses in the MMR-RIT and MMR II groups. Both MMR vaccines resulted in comparable reactogenicity profiles, and no safety concerns were detected. CONCLUSIONS: If licensed, the MMR-RIT could provide a valid option for the prevention of measles, mumps, and rubella in children in the United States and would reduce potential risks of a vaccine shortage.

Efficacy and safety of an oral live attenuated human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in Latin American infants: a randomised, double-blind, placebo-controlled phase III study.

BACKGROUND: Peak incidence of rotavirus gastroenteritis is seen in infants between 6 and 24 months of age. We therefore aimed to assess the 2-year efficacy and safety of an oral live attenuated human rotavirus vaccine for prevention of severe gastroenteritis in infants. METHODS: 15 183 healthy infants aged 6-13 weeks from ten Latin American countries randomly assigned in a 1 to 1 ratio to receive two oral doses of RIX4414 or placebo at about 2 and 4 months of age in a double-blind, placebo-controlled phase III study were followed up until about 2 years of age. Primary endpoint was vaccine efficacy from 2 weeks after dose two until 1 year of age. Treatment allocation was concealed from investigators and parents of participating infants. Efficacy follow-up for gastroenteritis episodes was undertaken from 2 weeks after dose two until about 2 years of age. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140673 (eTrack444563-023). FINDINGS: 897 infants were excluded from the according-to-protocol analysis. Fewer cases (p<0.0001) of severe rotavirus gastroenteritis were recorded for the combined 2-year period in the RIX4414 group (32 [0.4%] of 7205; 95% CI 0.3-0.6) than in the placebo group (161 [2.3%] of 7081; 1.9-2.6), resulting in a vaccine efficacy of 80.5% (71.3-87.1) to 82.1% (64.6-91.9) against wild-type G1, 77.5% (64.7-86.2) against pooled non-G1 strains, and 80.5% (67.9-88.8) against pooled non-G1 P[8] strains. Vaccine efficacy for hospital admission for rotavirus gastroenteritis was 83.0% (73.1-89.7) and for admission for diarrhoea of any cause was 39.3% (29.1-48.1). No cases of intussusception were reported during the second year of follow-up. INTERPRETATION: Two doses of RIX4414 were effective against severe rotavirus gastroenteritis during the first 2 years of life in a Latin American setting. Inclusion of RIX4414 in routine paediatric immunisations should reduce the burden of rotavirus gastroenteritis worldwide.

Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis.

BACKGROUND: The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial. METHODS: We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients). RESULTS: The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percent; P<0.001). During the 31-day window after each dose, six vaccine recipients and seven placebo recipients had definite intussusception (difference in risk, -0.32 per 10,000 infants; 95 percent confidence interval, -2.91 to 2.18; P=0.78). CONCLUSIONS: Two oral doses of the live attenuated G1P[8] HRV vaccine were highly efficacious in protecting infants against severe rotavirus gastroenteritis, significantly reduced the rate of severe gastroenteritis from any cause, and were not associated with an increased risk of intussusception. (ClinicalTrials.gov numbers, NCT00139347 and NCT00263666.)

Immunotoxicity and environment: immunodysregulation and systemic inflammation in children.

Environmental pollutants, chemicals, and drugs have an impact on children's immune system development. Mexico City (MC) children exposed to significant concentrations of air pollutants exhibit chronic respiratory inflammation, systemic inflammation, neuroinflammation, and cognitive deficits. We tested the hypothesis that exposure to severe air pollution plays a role in the immune responses of asymptomatic, apparently healthy children. Blood measurements for markers of immune function, inflammatory mediators, and molecules interacting with the lipopolysaccharide recognition complex were obtained from two cohorts of matched children (aged 9.7 +/- 1.2 years) from southwest Mexico City (SWMC) (n = 66) and from a control city (n = 93) with criteria pollutant levels below current standards. MC children exhibited significant decreases in the numbers of natural killer cells (p = .003) and increased numbers of mCD14+ monocytes (p < .001) and CD8+ cells (p = .02). Lower concentrations of interferon gamma (p = .009) and granulocyte-macrophage colony-stimulating factor (p < .001), an endotoxin tolerance-like state, systemic inflammation, and an anti-inflammatory response were also present in the highly exposed children. C-reactive protein and the prostaglandin E metabolite levels were positively correlated with twenty-four- and forty-eight-hour cumulative concentrations of PM(2.5). Exposure to urban air pollution is associated with immunodysregulation and systemic inflammation in children and is a major health threat.

Long-term Immunogenicity and Safety of the AS04-adjuvanted Human Papillomavirus-16/18 Vaccine in Four- to Six-year-old Girls: Three-year Follow-up of a Randomized Phase III Trial.

BACKGROUND: The burden of human papillomavirus (HPV) diseases is high in Latin America. HPV vaccines licensed from 2006 onwards offer protection against most HPV-related cancers, especially when introduced into national immunization programs. Barriers to optimal vaccine uptake are, however, lowering the impact of adolescent HPV vaccination programs. Immunization of children might overcome these barriers and be a strategy of choice for some countries. METHODS: This multicenter phase III randomized, controlled, single-blind study (NCT01627561) was conducted in Colombia, Mexico and Panama to assess safety and immunogenicity of 2-dose vaccination with AS04-adjuvanted HPV-16/18 vaccine in girls 4-6 years of age. We report safety outcomes and anti-HPV-16/18 antibody titers measured by enzyme-linked immunosorbent assay in HPV-vaccinated girls that were followed over a 36-month period. RESULTS: Over 36 months (ie, 30 months after the second vaccine dose), among 74 girls included in the HPV group, 1 serious adverse event unrelated to vaccination has been reported. No withdrawal because of (serious) adverse events has been reported. At month 36, all girls in the per-protocol-cohort were still seropositive for anti-HPV-16 and anti-HPV-18 with geometric mean concentrations of 1680.6 and 536.4 enzyme-linked immunosorbent assay units/mL, respectively. CONCLUSIONS: The AS04-adjuvanted HPV-16/18 vaccine administered according to a 2-dose schedule to girls 4-6 years of age induced a high and sustained immunologic response with an acceptable safety profile during the 30 months following vaccination.

Case Report: Chest Wall Tuberculosis without Pulmonary Involvement in Three Pediatric Immunocompetent Patients.

Primary rib cage tuberculosis (TB) is an infrequent form of presentation and represents 1% of all cases of osteoarticular TB. We report three cases of children who were previously healthy and who began with swelling of the anterior surface of the rib as initial manifestation of TB. The most important clinical presentations in this series were swelling and pain, with lytic lesions and a soft tissue mass in image studies simulating oncologic pathologies. Because none of the cases had positive epidemiological contact, TB was initially not considered, so the delay in diagnosis from the onset of symptoms was 4, 1, and 2 months, respectively. The diagnosis was made through histomorphological analyses. Treatment was administered during 12, 10, and 9 months. Posttreatment studies did not show any evidence of extrapulmonary TB and until date, the patients remained without relapse or active disease. The findings in our cases illustrate that the diagnosis of chest wall TB should be suspected in all patients from endemic areas who present rib injury.

Immunogenicity and safety of the 4CMenB and MenACWY-CRM meningococcal vaccines administered concomitantly in infants: A phase 3b, randomized controlled trial.

BACKGROUND: Invasive meningococcal disease has its highest incidence in infants. Co-administration of serogroup B (4CMenB) and quadrivalent conjugate (MenACWY-CRM) vaccines could protect against 5 clinically-relevant meningococcal serogroups. METHODS: This phase 3b, open, multicenter study (NCT02106390), conducted in Mexico and Argentina, enrolled and randomized (1:1:1) 750 healthy infants to receive either 4CMenB co-administered with MenACWY-CRM (4CMenB/MenACWY group), 4CMenB (4CMenB group), or MenACWY-CRM alone (MenACWY group) at ages 3, 5, 7 and 13 months. Non-inferiority of immune responses of co-administration to single administration of vaccines was assessed at 1 month post-booster dose (primary objective). Immunogenicity was evaluated pre- and 1 month post-primary and booster vaccinations using human serum bactericidal assay (hSBA). Safety was assessed. RESULTS: At 1 month post-booster vaccination, between-group hSBA geometric mean titer (GMT) ratios ranged from 0.89 to 1.03 for serogroup B strains (group 4CMenB/MenACWY over 4CMenB), and from 1.05 to 2.48 for ACWY serogroups (group 4CMenB/MenACWY over MenACWY). The lower limit of the 2-sided 95% confidence intervals for all GMT ratios was >0.5; the primary objective was demonstrated. Across all groups and serogroup B strains, 68-100% and 87-100% of children had hSBA titers ≥5 at 1 month post-primary and booster vaccination, respectively. For serogroups ACWY, ≥96% (post-primary vaccination) and ≥98% (post-booster vaccination) of children in all groups had hSBA titers ≥4. Post-booster vaccination, GMTs increased ≥5.99-fold from pre-booster values for each strain/serogroup. Solicited adverse events (AEs) were more frequent in groups 4CMenB/MenACWY and 4CMenB than in MenACWY; incidence of all other AEs was similar between groups. Serious AEs were reported for 6, 13, and 11 participants in groups 4CMenB/MenACWY, 4CMenB, and MenACWY, respectively; 1 (group 4CMenB) was considered vaccine-related. CONCLUSION: Immune responses elicited by co-administration of 4CMenB and MenACWY-CRM was non-inferior to single immunization. Co-administration of vaccines was immunogenic and well tolerated in infants. ClinicalTrials.gov: NCT02106390.

Economic burden of varicella complications in two referral centers in Mexico.

Varicella-zoster virus causes varicella (chicken-pox), mainly in young children. Most cases are mild but serious complications can occur, resulting in significant morbidity and mortality. The objective of this study was to estimate the cost burden of varicella hospitalizations in two pediatric reference hospitals in Mexico. This retrospective observational study collected data on patients aged <18 years admitted to two third-level referral hospitals in Mexico. Cases were identified from hospital records using International Classification of Diseases Ninth Revision (ICD-9) codes 052 Chickenpox, or Tenth Revision (ICD-10) codes B01 Varicella (chickenpox). Data on demographic and clinical characteristics and resource use were collected from hospital records. Costs for hospital stay and interventions were obtained from the Mexican Institute for Social Security for 2015 and updated to 2017 costs. A total of 172 hospitalized varicella clinically-confirmed cases and 121 varicella- contacts (with epidemiological linkage to a clinically-confirmed case) were included. Thirty eight of the 172 cases (22.0%) experienced complications. There were no deaths. The median duration of hospitalization was 12 days for cases and 23 days for contacts. The median hospitalization cost was MXN 82,572 (USD 4,434) per case, and MXN 89,453 (USD 4,804) per contact. Although considered a mild disease, varicella was associated with a substantial cost burden in two Mexican third-level referral hospitals.

Varicella epidemiology in Latin America and the Caribbean.

INTRODUCTION: The Latin American Society of Pediatric Infectious Diseases (SLIPE), with the support of the Americas Health Foundation (AHF), has developed a position paper on varicella prevention in Latin America and Caribbean countries (LAC). This article summarizes the most relevant aspects of varicella in LAC, and emphasizes the need to include the varicella vaccine in the national immunization programs in the Region and evaluate its impact disease burden. AREAS COVERED: A systematic review was conducted of the medical evidence published and presented at various regional medical conferences on the disease burden in LAC, the advances made by prevention programs, the available vaccines in the Region, and their immunogenicity, efficacy, effectiveness, and safety. The different national varicella-prevention vaccination programs were reviewed, as was available information regarding the impact of these programs on the epidemiology of varicella in those countries implementing a varicella vaccine strategy. Following that initial publication, an update was conducted, including data from additional countries in the Region. EXPERT COMMENTARY: Varicella is a vaccine-preventable infectious disease, considered a 'benign disease' because of lower complication rates when compared with measles, pertussis. The incorporation of a two-dose varicella vaccine in national immunization schedules in all countries throughout LAC would be of great benefit to the health of the children.