Efficacy of a tetravalent dengue vaccine in children in Latin America.

BACKGROUND: In light of the increasing rate of dengue infections throughout the world despite vector-control measures, several dengue vaccine candidates are in development. METHODS: In a phase 3 efficacy trial of a tetravalent dengue vaccine in five Latin American countries where dengue is endemic, we randomly assigned healthy children between the ages of 9 and 16 years in a 2:1 ratio to receive three injections of recombinant, live, attenuated, tetravalent dengue vaccine (CYD-TDV) or placebo at months 0, 6, and 12 under blinded conditions. The children were then followed for 25 months. The primary outcome was vaccine efficacy against symptomatic, virologically confirmed dengue (VCD), regardless of disease severity or serotype, occurring more than 28 days after the third injection. RESULTS: A total of 20,869 healthy children received either vaccine or placebo. At baseline, 79.4% of an immunogenicity subgroup of 1944 children had seropositive status for one or more dengue serotypes. In the per-protocol population, there were 176 VCD cases (with 11,793 person-years at risk) in the vaccine group and 221 VCD cases (with 5809 person-years at risk) in the control group, for a vaccine efficacy of 60.8% (95% confidence interval [CI], 52.0 to 68.0). In the intention-to-treat population (those who received at least one injection), vaccine efficacy was 64.7% (95% CI, 58.7 to 69.8). Serotype-specific vaccine efficacy was 50.3% for serotype 1, 42.3% for serotype 2, 74.0% for serotype 3, and 77.7% for serotype 4. Among the severe VCD cases, 1 of 12 was in the vaccine group, for an intention-to-treat vaccine efficacy of 95.5%. Vaccine efficacy against hospitalization for dengue was 80.3%. The safety profile for the CYD-TDV vaccine was similar to that for placebo, with no marked difference in rates of adverse events. CONCLUSIONS: The CYD-TDV dengue vaccine was efficacious against VCD and severe VCD and led to fewer hospitalizations for VCD in five Latin American countries where dengue is endemic. (Funded by Sanofi Pasteur; ClinicalTrials.gov number, NCT01374516.).

Analysis of the trend of hospitalizations for asthma in children and adolescents in Brazil.

OBJECTIVE: To analyze the trend of hospitalizations for asthma in children and adolescents by region and age group in Brazil, from 2008 to 2017. METHOD: This is a time-series study with secondary data regarding hospitalizations for asthma in children and adolescents, according to age, region, and gender. Descriptive statistics procedures were used with measures of central tendency to calculate the variation between the periods of 2008 and 2017. Rates of hospitalizations were calculated specifically by age group and region. Time trend analysis was performed by simple linear regression, considered as stationary (p>0.05), declining (p<0.05 and negative regression coefficient), or ascending (p<0.05) and positive regression coefficient). RESULTS: The present study identified a higher proportion of hospitalizations for asthma in Brazil in children aged 5-9 years. Regarding gender, there were more hospitalizations in boys. The region that presented the highest proportion of hospitalizations, in all age groups investigated, was the Northeast. As for the trend analysis, this article showed that, in Brazil, there was a trend toward a reduction in hospitalization rates for asthma. CONCLUSION: In Brazil, there was a tendency to reduce hospitalizations for all investigated age groups. The Northeast was the only region that showed a decline in all age groups.

Prospective cohort study with active surveillance for fever in four dengue endemic countries in Latin America.

To prepare for a Phase III dengue vaccine efficacy trial, 20 investigational sites were selected for this observational study to identify dengue infections in a closed cohort (N = 3,000 children 9-16 years of age). Of 255 acute febrile episodes experienced by 235 children, 50 (21.3%) were considered serologically probable dengue, and 18 (7.7%) were considered virologically confirmed (i.e., dengue NS1 antigen positive) dengue cases. Considering the disease-free and at-risk period from study start to onset of symptoms, the overall incidence density of acute febrile episodes was 17.7 per 100 person-years of follow-up, ranging from 15.3 in Colombia to 22.0 in Puerto Rico. This study showed that all sites were capable of capturing and following up acute febrile episodes within a specific timeframe among the established cohort and to detect dengue cases.

Effectiveness of Haemophilus influenzae b conjugate vaccine on childhood pneumonia: a case-control study in Brazil.

BACKGROUND: The conjugate Haemophilus influenzae type b (Hib) vaccine has been highly efficacious in reducing type b H. influenzae meningitis. However, information is limited about its impact on childhood pneumonia after vaccine introduction into the routine programme. This study evaluated the effectiveness of Hib conjugate vaccine in the reduction of community-acquired pneumonia among infants in Central Brazil. METHODS: A matched case-control study was built into an ongoing prospective population-based surveillance of pneumonia, enrolling 1293 participants between May 2000 and August 2001. Cases (n = 431) were children