Alicia Montano

Impact of Universal Pneumococcal Vaccination on Hospitalizations for Pneumonia and Meningitis in Children in Montevideo, Uruguay

Background: In March 2008, Uruguay included PCV7 into the routine vaccination program, in a 2 + 1 schedule for children <2 years of age. Catch-up immunization was offered to children born in 2007. Greater than 95% of children received their first and second doses. The aim of this study was to assess the effect of this strategy. Methods: Annual hospitalization rates (per 10,000 discharges) for community-acquired pneumonia (CAP) in children <14 years of age and pneumococcal meningitis are described prior to PCV7 vaccination (2005–2007), during the year of implementation (2008) and following vaccine introduction (2009). Data regarding age, diagnosis, vaccination status, and pneumococcal serotype were obtained from Hospital Pereira Rossell databases and vaccination records. Results: Comparison of hospitalization rates for CAP and pneumococcal-CAP (P-CAP) between prevaccine years (2005–2007) and the year after vaccination (2009) decreased significantly in all children by 56% and 48.2%, respectively. Significant reduction was observed for vaccine serotype P-CAP (serotype 14 P-CAP decreased from 26.6 to 2.5 per 10,000 discharges) in children <2 years of age. A significant reduction in pneumococcal meningitis of 59% was seen in this age group; median rates prevaccination decreased from 17 (12.2–24.9) to 7 (3–11.8) after the administration of vaccine. No vaccine failures for P-CAP or pneumococcal meningitis were seen in fully immunized children. Conclusions: One year after PCV7 introduction into the routine vaccination schedule of Uruguay, there was a rapid and significant reduction in rates of CAP, P-CAP, and pneumococcal meningitis in children <2 years of age.

Changes in hospitalizations for pneumonia after universal vaccination with pneumococcal conjugate vaccines 7/13 valent and haemophilus influenzae type b conjugate vaccine in a Pediatric Referral Hospital in Uruguay.

Background: In 1994, Uruguay included Haemophilus influenzae b (Hib) conjugated vaccine in a 3 + 1 schedule. In March 2008, 7-valent pneumococcal conjugate vaccines (PCV7) was included in a 2 +1 schedule. In 2010, 13-valent PCV replaced PCV7. Catch-up immunization was offered. The aim of this study was to describe the etiology of community-acquired pneumonia (CAP) in children 0–14 years of age hospitalized at the Hospital Pediatrico-Centro Hospitalario Pereira Rossell between 2003 and 2012. Methods: Annual hospitalization rates (per 10,000 discharges) for CAP and bacterial-confirmed CAP in children 0–14 years of age was described prior PCV7 vaccination (2003–2007), during the year of implementation of PCV7 (2008) and after the introduction of PCV7 (2009–2012). Data regarding age, strains isolated from pleural fluid and/or blood, vaccination status, pneumococcal and H. influenzae serotypes were obtained from Hospital Pediatrico-Centro Hospitalario Pereira Rossell databases and vaccination records. Results: Hospitalization rates for CAP and pneumococcal CAP between prevaccine years and the last year after introduction of vaccination with PCV (2012) significantly decreased by 78.1% and 92.4%, respectively. Significant reduction for 13-valent PCV vaccine serotypes and significant increase for nonvaccine serotypes was observed. A decrease in Staphylococcus aureus pneumonia was observed. Hospitalization rates for H. influenzae CAP remain stable before and after pneumococcal vaccination. Conclusions: Three years after PCV7/13 introduction into the routine vaccination schedule, there was a rapid and significant reduction in rates of CAP and P-CAP. An increase of etiology of CAP by other agents was not observed.

Standard case management of pneumonia in hospitalized children in Uruguay, 1997 to 1998

Objective. To report the results of the use of antimicrobial guidelines for the management of children with community-acquired bacterial pneumonia. Methods. Admittance and discharge criteria and algorithms for diagnosis and treatment were established. The decision to treat with antibiotics was based on radiologic findings in pneumonia with pulmonary consolidation and left to the attending physician’s criteria in the remaining cases. The use of antibiotics was limited to penicillin and derivatives (ampicillin, amoxicillin) and macrolides. Results. Of the 1163 children treated as bacterial pneumonia, hospitalized in public and private health facilities in Montevideo from September, 1997, through September, 1998, standard case management was applied in 1082 (93%). Age distribution was: <1 month, 1%; between 1 and 11 months, 29%; between 1 and 5 years, 50%; >5 years, 20%. Chest radiography showed evidence of pulmonary consolidation in 843 children (73%). Bacteria were detected in blood culture and/or pleural fluid of 57 children (5%). In 51 the identified microorganism was Streptococcus pneumoniae, susceptible to penicillin in 30, intermediate in 6 and resistant in 5 (maximum MIC, 4 &mgr;g/ml); in 10 cases etiologic diagnosis was made by antigen detection. Empyema was present in 62 children (5.3%); 38 (3.27%) required treatment in an intensive care unit; and 5 (0.4%) died. Conclusions. Compliance with standard case management was highly satisfactory. Outcome of children treated with penicillin and derivatives was good, including children with empyema and pneumatocele and two patients with penicillin-resistant S. pneumoniae. At the present time S. pneumoniae resistant to penicillin is not an important problem in children with pneumonia in Uruguay. Surveillance of identified microorganisms and their antimicrobial susceptibility must continue.

Ampicillin and penicillin concentration in serum and pleural fluid of hospitalized children with community-acquired pneumonia.

Background: Optimal therapeutic efficacy of β-lactam antibiotics for treatment of pneumococcal pneumonia is thought to be associated with the serum concentration greater than the minimum inhibitory concentration for 40–50% of the interdose interval at site of infection. Objective: Establish whether intravenous administration of ampicillin 400 mg/kg/day or penicillin 200,000 IU/kg/day in 6 divided doses reaches serum and or pleural concentrations above 4 μg/ml for at least 40% of the interdose interval. Materials and Methods: Hospitalized healthy children 1 month–14 years old with community-acquired bacterial pneumonia and empyema were eligible. Blood samples were obtained 30 min (C1) and 3 h (C2) after an antibiotic dose. Pleural fluid samples were obtained 1 and 4 h after the same dose in which blood samples were obtained. The concentrations were measured by high performance liquid chromatography. Results: The study included 17 patients treated with ampicillin and 13 treated with penicillin. For ampicillin, mean serum concentrations were C1 37.3 ± 19 μg/ml and C2 11 ± 10.2 μg/ml and mean pleural fluid concentrations were C1 25.8 ± 9.9 μg/ml and C2 16.2 ± 7.9 μg/ml. For penicillin, mean serum concentrations were C1 21.8 ± 16.4 μg/ml and C2 23.9 ± 3.4 μg/ml. Mean pleural fluid concentrations were C1 10.9 ± 2.2 μg/ml and C2 7.7 ± 3.4 μg/ml. In 8 of 30 patients, serum C2 was <4 μg/ml; in all of them serum concentrations were >4 μg/ml for >40% of the interdose interval. Conclusions: This study of the pharmacokinetics of β-lactam antibiotics in children with bacterial pneumonia may help in the development of therapeutic guidelines for the treatment of pneumococcal pneumonia.

Seroprevalence of anti-polio antibodies in a population 7 months to 39 years of age in Uruguay: implications for future polio vaccination strategies.

This study evaluated the seroprevalence of poliovirus types 1, 2 and 3 antibodies and vaccination coverage in 780 subjects aged between 7 months and 39 years in Montevideo, Uruguay, where oral polio vaccine (OPV) is used. Antibody titers were measured and seroprotection rates and geometric mean titers (GMTs) were compared among four age groups. Vaccination histories were recorded from documents and interviews. Seroprotection rates ranged from 72% to 95% in children aged 7-23 months, 31-77% in 2-9-year olds, 14-45% in 10-19-year olds and 20-59.5% in 20-39-year olds. Seroprotection decreased significantly with increasing age (p<0.05). Polio vaccination coverage was >90% for the two youngest age groups. These results could help guide public policy decisions regarding polio vaccination, and support the use of inactivated polio vaccine following cessation of OPV.