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R Lagos

Publications and source records attributed to R Lagos.

At least 19 recordsLinked to original sources
PubMed1999

Immunogenicity of 2 serogroup B outer-membrane protein meningococcal vaccines: a randomized controlled trial in Chile.

CONTEXT: Meningococcal disease occurs worldwide, and serogroup B disease accounts for a large proportion of cases. Although persons younger than 4 years are at greatest risk for serogroup B meningococcal disease, vaccine efficacy has not been demonstrated in this age group. OBJECTIVE: To evaluate serum bactericidal activity (SBA) against homologous vaccine type strains and a heterologous Chilean epidemic strain of Neisseria meningitidis as a potential correlate for vaccine efficacy. DESIGN: Double-blind, randomized controlled trial conducted between March 14 and July 20, 1994. All blood samples were taken by December 1994. SETTING: Santiago, Chile, where a clonal serogroup B meningococcal disease epidemic began in 1993. PARTICIPANTS: Infants younger than 1 year (n = 187), children aged 2 to 4 years (n = 183), and adults aged 17 to 30 years (n = 173). INTERVENTION: Participants received 3 doses of outer-membrane protein (OMP) meningococcal vaccine developed in either Cuba or Norway or a control vaccine, with each dose given 2 months apart. Blood samples were obtained at baseline, prior to dose 3, and at 4 to 6 weeks after dose 3. MAIN OUTCOME MEASURE: Immune response, defined as a 4-fold or greater rise in SBA titer 4 to 6 weeks after dose 3 compared with prevaccination titer. RESULTS: Children and adult recipients of either meningococcal vaccine were more likely than controls to develop an immune response to the heterologous epidemic strain. After 3 doses of vaccine, 31% to 35% of children responded to the vaccine vs 5% to placebo; 37% to 60% of adults responded to vaccine vs 4% to placebo (P<.05 vs control for all). Infants, however, did not respond. In contrast, against homologous vaccine type strains, the response rate was 67% or higher among children and adults and 90% or higher among infants (P<.001 vs control for all). Subsequent SBA against 7 isogenic homologous target strains identified class 1 OMP as the immunodominant antigen. CONCLUSIONS: These data suggest that neither serogroup B OMP meningococcal vaccine would confer protection during a heterologous epidemic. However, epidemic strain-specific vaccines homologous for class 1 OMP are promising candidates for the control of epidemic serogroup B meningococcal disease.

Adolescent↗
PubMed1999

Effect of small bowel bacterial overgrowth on the immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR.

Several live oral vaccines (polio, bovine rotavirus, CVD 103-HgR cholera) are less immunogenic in developing than in industrialized countries. It was hypothesized that proximal small bowel bacterial overgrowth (common in children in less developed countries but rare in industrialized settings) diminishes the vibriocidal antibody response to CVD 103-HgR. In total, 202 fasting Santiago schoolchildren aged 5-9 years had lactulose breath H2 tests to detect proximal small bowel bacteria 1 day before ingesting CVD 103-HgR. Florid small bowel overgrowth was observed in 10 (5.6%) of 178 analyzable children. In children with florid overgrowth, vibriocidal seroconversion differed little from other children (60% vs. 67%), but the geometric mean titer was lower (160 vs. 368; P=.25). By logistic regression, increased peak breath H2 at small bowel time points was associated with diminished seroconversion (P=.04), as was the interaction of H2 value and weight (children >25 kg had lower seroconversion rates among subjects with heaviest overgrowth).

Administration, Oral↗
PubMed1999

Population-based study of the incidence of Shigella diarrhea and causative serotypes in Santiago, Chile.

BACKGROUND: Shigella is an important cause of diarrheal disease in children in developing countries. The increasing prevalence of antibiotic-resistant strains has stimulated interest in the use of multivalent Shigella vaccines. Because Shigella vaccines under development are based on eliciting immunity to O antigens, monitoring the distribution of serotypes in defined target populations is critical. We initiated health center-based surveillance in a poor semirural community in Colina, Santiago (7489 children <60 months of age) to determine the age-specific incidence of Shigella disease and the responsible serotypes. FINDINGS: Surveillance was maintained at the 2 health centers during warm seasons (November 1 through April 30) for 4 successive years (1994 to 1998). Shigella was recovered from 54 of 243 cases of dysentery (22%) and from 215 of 3966 cases of nondysenteric diarrhea (5.4%) (P < 0.001). The peak mean annual incidence of shigellosis occurred among children 12 to 47 months of age (9.0 to 12.6 cases/10(3) children), although the incidence in infants (5.2/10(3)) and children 48 to 59 months of age (6.2/10(3)) was also substantial. During the 1995 through 1996 season, an age-matched healthy control was cultured for every child <60 months of age with diarrhea. Shigella isolation from cases (34 of 576, 5.9%) was >8-fold higher than controls (4 of 576, 0.7%) (P < 0.01). Four serotypes, Shigella sonnei (45%), Shigella flexneri 2b (19%), S. flexneri 2a (14%) and S. flexneri 6 (11%), accounted for 89% of all cases. INTERPRETATION: Shigella remains an important pediatric pathogen in Santiago. The serotype distribution from Colina, which closely resembles data from a population-based surveillance study in Santiago in the mid-1980s, demonstrates a remarkable degree of serotype stability in Santiago during a 15-year period.

Case-Control Studies↗
PubMed1999

Palatability, reactogenicity and immunogenicity of engineered live oral cholera vaccine CVD 103-HgR in Chilean infants and toddlers.

BACKGROUND: Live oral cholera vaccine CVD 103-HgR is well-tolerated and immunogenic when administered to adults, school age children and preschool children in a single 5 x 10(9) colony-forming unit dose. Because elicitation of immune responses after administration of a single dose is exceptional for any oral vaccine in any age group, CVD 103-HgR was used as a probe to investigate the clinical acceptability, practicality and immunogenicity of this vaccine in infants and toddlers 3 to 17 months of age. METHODS: The study was undertaken successively in 12- to 17-month-olds (n = 104), 7- to 11-month-olds (n = 106) and 3- to 5-month-olds (n = 102). One-half of the subjects were randomly allocated to receive vaccine and the other one-half to receive placebo, in double blind fashion. After 2 weeks of double blind follow-up, all subjects received a dose of vaccine. Vibriocidal antibody titers were measured on coded sera collected at baseline and 2 weeks after each dosing. The buffered vaccine "cocktail" had a volume of 100 ml; subjects who ingested > or =70 ml were considered fully vaccinated. FINDINGS: Only 37% of subjects overall (25% of 3- to 5-month-olds) ingested > or =70 ml of the cocktail. The vaccine was well-tolerated with no significant differences in the rate or severity of adverse reactions after ingestion of vaccine vs. placebo. Seroconversion after ingestion of a single dose of CVD 103-HgR was similar in fully vaccinated subjects (66%) and in those who ingested a smaller fraction of the vaccine cocktail (63%). Of subjects who ingested two doses, 5 of 118 excreted vaccine organisms on Day 7 after the first dose vs. 0 of 118 after the second dose. INTERPRETATION: Single dose oral CVD 103-HgR is well-tolerated and immunogenic in infants even when a partial dose is ingested. The buffered vaccine cocktail that is readily imbibed by older children is not appealing to young infants, and improved vaccine formulations and delivery vehicles for immunizing infants must be sought.

Administration, Oral↗
PubMed1999

Defining the burden of pneumonia in children preventable by vaccination against Haemophilus influenzae type b.

OBJECTIVES: To determine the burden of pneumonia requiring hospitalization in infants and young children preventable by vaccination against Haemophilus influenzae type b (Hib). DESIGN: Vaccination centers in Santiago, Chile, were randomly selected to administer PRP-T, an Hib conjugate vaccine, combined with diphtheria-tetanus toxoids-pertussis (DTP) vaccine or DTP alone. SUBJECTS: Infants who received > or =2 doses of DTP or DTP and Hib conjugate vaccine combined. MAIN OUTCOME MEASURES: Pneumonia episodes leading to hospitalization accompanied by indicators of likely bacterial infection including radiologic evidence of alveolar consolidation or pleural effusion, an elevated erythrocyte sedimentation rate (> or =40 mm/h) or bronchial breath sounds on auscultation. RESULTS: In participants age 4 to 23 months, PRP-T reduced the incidence of pneumonia associated with alveolar consolidation or pleural effusion by 22% (95% confidence interval, -7 to 43) from 5.0 to 3.9 episodes per 1000 children per year. When the pneumonia case definition included any of the following, alveolar consolidation, pleural effusion, erythrocyte sedimentation rate > or =40 mm/h or bronchial breath sounds, PRP-T provided 26% protection (95% confidence interval, 7 to 44) and prevented 2.5 episodes per 1000 children per year. CONCLUSIONS: Hib vaccine provides substantial protection against nonbacteremic pneumonia, particularly those cases with alveolar consolidation, pleural effusion or other signs of likely bacterial infection. Hib vaccination prevented approximately 5 times as many nonbacteremic pneumonia cases in infants as meningitis cases, thus indicating that the largest part of the effect of Hib vaccination might be undetectable by routine culture methods.

Chile↗
PubMed1999

Helicity of alpha(404-451) and beta(394-445) tubulin C-terminal recombinant peptides.

We have investigated the solution conformation of the functionally relevant C-terminal extremes of alpha- and beta-tubulin, employing the model recombinant peptides RL52alpha3 and RL33beta6, which correspond to the amino acid sequences 404-451(end) and 394-445(end) of the main vertebrate isotypes of alpha- and beta-tubulin, respectively, and synthetic peptides with the alpha-tubulin(430-443) and beta-tubulin(412-431) internal sequences. Alpha(404-451) and beta(394-445) are monomeric in neutral aqueous solution (as indicated by sedimentation equilibrium), and have circular dichroism (CD) spectra characteristic of nearly disordered conformation, consistent with low scores in peptide helicity prediction. Limited proteolysis of beta(394-445) with subtilisin, instead of giving extensive degradation, resulted in main cleavages at positions Thr409-Glu410 and Tyr422-Gln423-Gln424, defining the proteolysis resistant segment 410-422, which corresponds to the central part of the predicted beta-tubulin C-terminal helix. Both recombinant peptides inhibited microtubule assembly, probably due to sequestration of the microtubule stabilizing associated proteins. Trifluoroethanol (TFE)-induced markedly helical CD spectra in alpha(404-451) and beta(394-445). A substantial part of the helicity of beta(394-445) was found to be in the CD spectrum of the shorter peptide beta(412-431) with TFE. Two-dimensional 1H-NMR parameters (nonsequential nuclear Overhauser effects (NOE) and conformational C alphaH shifts) in 30% TFE permitted to conclude that about 25% of alpha(404-451) and 40% of beta(394-451) form well-defined helices encompassing residues 418-432 and 408-431, respectively, flanked by disordered N- and C-segments. The side chains of beta(394-451) residues Leu418, Val419, Ser420, Tyr422, Tyr425, and Gln426 are well defined in structure calculations from the NOE distance constraints. The apolar faces of the helix in both alpha and beta chains share a characteristic sequence of conserved residues Ala,Met(+4),Leu(+7),Tyr(+11). The helical segment of alpha(404-451) is the same as that described in the electron crystallographic model structure of alphabeta-tubulin, while in beta(394-451) it extends for nine residues more, supporting the possibility of a functional coil --> helix transition at the C-terminus of beta-tubulin. These peptides may be employed to construct model complexes with microtubule associated protein binding sites.

Amino Acid Sequence↗
PubMed1999

Identification and properties of the genes encoding microcin E492 and its immunity protein.

The gene coding for the immunity protein (mceB) and the structural gene of microcin E492 (mceA), a low-molecular-weight channel-forming bacteriocin produced by a strain of Klebsiella pneumoniae, have been characterized. The microcin gene codes for a precursor protein of either 99 or 103 amino acids. Protein sequencing of the N-terminal region of microcin E492 unequivocally identified this gene as the microcin structural gene and indicated that this microcin is synthesized as a precursor protein that is cleaved at either amino acid 15 or 19, at a site resembling the double-glycine motif. The gene encoding the 95-amino-acid immunity protein (mceB) was identified by cloning the DNA segment that encodes only this polypeptide into an expression vector and demonstrating the acquisition of immunity to microcin E492. As expected, the immunity protein was found to be associated with the inner membrane. Analysis of the DNA sequence indicates that these genes belong to the same family as microcin 24, and they do not share structural motifs with any other known channel-forming bacteriocin. The organization of the microcin- and immunity protein-encoding genes suggests that they are coordinately expressed.

Amino Acid Sequence↗
PubMed1999

[Serum antibodies against hepatitis A virus among subjects of middle and low socioeconomic levels in urban area of Santiago, Chile].

BACKGROUND: The epidemiology of hepatitis A virus (HAV) infection is closely associated to the level of hygiene and sanitation of the population. Newly industrialising areas experience a transition from high to intermediate endemicity, which is characterized by a shift in the exposure age to HAV, from early childhood to school ages or adolescence. AIM: To measure the prevalence of HAV antibodies in subjects living in urban Santiago. SUBJECTS AND METHODS: A HAV antibody survey in five medium and low socioeconomic level urban districts of northern Santiago, was conducted in 1996. Healthy subjects aged 1 to 39 years old were recruited from randomly selected households. RESULTS: Five hundred three subjects were studied. Anti HAV antibodies were found in 13.2, 29.5, 59.6, 78.1, 95.6 and 98.2% of individuals aged 1 to 4, 5 to 9, 10 to 14, 15 to 19, 20 to 29 and 30 to 39 years old, respectively. CONCLUSIONS: The profile of positive antibodies is compatible with an intermediate pattern of transmission of HAV. The current data supports the idea that infection is shifting towards older ages. A progressive increase in the number of susceptible school age children and teenagers is propitious for the occurrence of common source hepatitis A outbreaks.

Adolescent↗
PubMed1999

[Systematic surveillance of influenza, syncytial respiratory, parainfluenza and adenovirus in children with acute respiratory infections].

BACKGROUND: The efficacy of influenza vaccination programs depends on the antigenic similitude between vaccine and the influenza virus circulating in the community. Therefore the surveillance of clinical activity and antigenic features of influenza virus is of utmost importance. AIM: To perform a systematic surveillance of clinical activity and antigenic characteristics of influenza virus. MATERIAL AND METHODS: Since 1996 and during the cold months (May to September), 20 samples of upper respiratory secretions per week, were obtained from children with acute respiratory infections consulting to the emergency room of a public hospital. Using indirect immunofluorescence and cellular cultures, the presence of influenza, syncytial respiratory, parainfluenza and adenovirus was assessed. The weekly number of consultations in the emergency room and the number of hospital discharges due to acute respiratory infections, were registered. RESULTS: Influenza and syncytial respiratory were the predominant virus detected since 1996. In 1996 and 1998, the weekly detection of influenza virus followed a single seasonal curve. The maximal weekly positively results reached 85 and 80% of the obtained samples, respectively. During 1997, two curves of influenza virus activity were observed, but none reached more than 50% of weekly positive samples. The demand for outpatient care evolved in parallel to the weekly detection of influenza virus. The hospital discharges due to acute respiratory infections paralleled the syncytial respiratory virus detection rates. CONCLUSIONS: This surveillance model is effective for the detection of influenza and other virus responsible for acute respiratory infections and their relationship with the demand for health care during the cold months.

Acute Disease↗
PubMed1999

[Birth weight difference in 3 biological variables in normal newborns].

BACKGROUND: The most important determinant of birth weight is gestational age. However, other biological variables may influence this parameter. AIM: To study the influence of maternal parity, height and neonatal gender on the birth weight of normal newborns in a public Hospital of Southern Chile. MATERIAL AND METHODS: A computer registry of all deliveries attended in Temuco Hospital between 1993 and 1998 was analyzed. Normal deliveries giving birth to newborns of more than 2,500 g and from women who did not suffer from conditions that could influence birth weight, such as hypertension, undernutrition or smoking, were selected. RESULTS: From 27,736 deliveries, 12,580 were selected for the study. Male newborns with gestational ages from 37 to 42 weeks, had a higher weight than their female counterparts. Multiparous women and those with a height over 154 cm gave birth to newborns with a higher weight than nulliparous women or than those with a height of less than 154 cm. CONCLUSIONS: According to these results, birth weight must be corrected by gender and maternal features, to define those newborns that have a low birth weight for their gestational age.

Birth Weight↗
PubMed1998

Economisation of vaccination against Haemophilus influenzae type b: a randomised trial of immunogenicity of fractional-dose and two-dose regimens.

BACKGROUND: The cost of Haemophilus influenzae type b (Hib) conjugate vaccines has limited their use in non-industrialised countries. To identify more economical vaccination schedules, we carried out a randomised trial of the immunogenicity of alternative regimens to the standard three-dose series. METHODS: 627 Chilean infants were randomly allocated to one of four regimens with either Hib polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) or Hib oligosaccharide-diphtheria mutant toxoid conjugate vaccine (PRP-CRM197), for a total of eight groups. All infants receive diphtheria-tetanus-pertussis (DTP) vaccine at ages 2, 4, and 6 months. The regimens included three full doses, three fractional doses consisting of one half or one third of the full dose, and a regimen of two full doses (at age 4 and 6 months). The primary outcome was the proportion of infants with serum anti-polyribosylribitol phosphate (PRP, the type b capsular polysaccharide) concentrations of 0.15 microg/mL or more at age 8 months. FINDINGS: 93% (95% CI 85-98) of infants vaccinated with three full doses of PRP-T or PRP-CRM197 (95% CI 84-98) achieved anti-PRP concentrations of 0.15 microg/mL or more at age 8 months, compared with 91% (83-96) to 100% (95-100) of infants immunised with any fractional-dose regimen. Of the infants vaccinated with two doses of PRP-T or PRP-CRM197, 99% (93-100) and 87% (77-93) developed anti-PRP concentrations of 0.15 microg/mL or more, respectively. INTERPRETATION: 91% (83-96) to 100% (95-100) of infants immunised with one-half or one-third of a full dose of Hib conjugate developed protective antibody concentrations. Carrier priming with DTP may make two-dose schedules an option in some places. These alternative regimens could bring the cost of Hib vaccines within reach of countries that currently cannot afford them.

Bacterial Proteins↗
PubMed1998

Safety and immunogenicity of low and high doses of trivalent live cold-adapted influenza vaccine administered intranasally as drops or spray to healthy children.

The safety and immunogenicity of various doses of trivalent cold-adapted influenza vaccine (CAIV-T) administered intranasally by drops or spray to children aged 18-71 months was examined. CAIV-T containing A/Johannesburg/33/94 (H3N2), B/Panama/45/90, and A/Texas/36/91 (H1N1) was safe and well-tolerated. At the highest CAIV-T dose, 90%, 50%, and 16% of initially seronegative subjects seroconverted to the H3N2, B, and H1N1 antigens, respectively. The lower immunologic response to the H1N1 vaccine strain compared with the other strains was associated with a low frequency of H1N1 shedding. No statistically significant differences in reactogenicity or immunogenicity were detected between subjects who received CAIV-T by drops or spray. In conclusion, this CAIV-T was safe and induced acceptable immunologic responses to 2 of the 3 vaccine strains. Studies are needed to confirm previous observations that receipt of two doses of this vaccine results in immunologic responses that confer protection to all 3 circulating influenza virus strains.

Administration, Intranasal↗
PubMed1998

Epidemiology of invasive pneumococcal infections in infants and young children in Metropolitan Santiago, Chile, a newly industrializing country.

AIM: To study the epidemiology of invasive pneumococcal infections in infants and young children in Santiago, Chile, as a representative pediatric population in a newly industrializing country where pneumococcal conjugate vaccines may be used in the future. METHODS: A 5-year retrospective laboratory-based review (1989 to 1993) was followed by a 3-year prospective laboratory and hospital surveillance study in two of the six health administrative areas of Santiago to detect all hospitalized cases of invasive pneumococcal disease (defined as Streptococcus pneumoniae isolated from blood, cerebrospinal fluid or another normally sterile site) among infants and children (0 to 23 months of age in the retrospective and 0 to 59 months of age in the prospective study). RESULTS: During the 5-year retrospective survey the incidence of invasive pneumococcal disease was 90.6 cases per 10(5) infants 0 to 11 months old and 18.5 cases per 10(5) toddlers 12 to 23 months old. Similar rates (60.2 per 10(5) infants and 18.1 per 10(5) toddlers) were recorded during the 3 years of prospective surveillance. Among the 110 cases in children 0 to 59 months of age detected during the 3-year prospective surveillance, 2 clinical forms, pneumonia and meningitis, accounted for 87.2% of all cases; 13 of the 49 pneumonia patients (26%) had empyema as a complication. Notably 40 of the 110 cases (36.4%) occurred before 6 months of age (63.4% of the 63 infant cases). Serotypes 1, 14, 5 and 6B were the most prevalent. Overall 76 and 69%, respectively, of S. pneumoniae isolates were antigenic types that would be covered by the 11- or 9-valent conjugate vaccines under development. CONCLUSIONS: Invasive pneumococcal infections in Santiago, Chile, exhibit an epidemiologic pattern intermediate between that of developing and industrialized countries. The high burden of disease in early infancy dictates that an accelerated immunization schedule (beginning in the perinatal period) or maternal immunization with pneumococcal vaccines should be explored.

Age Factors↗
PubMed1998

Clinical acceptability and immunogenicity of a pentavalent parenteral combination vaccine containing diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis and Haemophilus influenzae type b conjugate antigens in two-, four- and six-month-old Chilean infants.

BACKGROUND: In recent years additional parenteral vaccines have been recommended for routine immunization of infants in the US and elsewhere. The ability to administer multiple vaccines as a single injection without unacceptably increasing reactogenicity or decreasing immunogenicity of any component would offer many practical advantages. METHODS: A randomized, open, controlled trial was conducted to assess the tolerance profile and immunogenicity, as well as to identify potential antigenic interferences, resulting from administration of a parenteral combination vaccine for infants. The vaccine contains diphtheria and tetanus toxoids, acellular pertussis antigens (DTaP), enhanced inactivated poliovirus (eIPV) and Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T). Infants (n=711) were randomly assigned to receive 1 of 5 regimens as the primary series at 2, 4 and 6 months of age, by group: (1) DTaP plus oral polio vaccine (OPV); (2) DTaP plus eIPV (separate injections); (3) DTaP-eIPV combined as a single injection; (4) DTaP-eIPV combined, plus a separate injection of PRP-T; or (5) DTaP-eIPV combined and reconstituting PRP-T, as a single injection. At 3, 5 and 7 months Groups 1, 2 and 3 received PRP-T. At 12 months all infants received a booster dose of DTaP reconstituting PRP-T as a single injection, plus a separate injection of measles, mumps and rubella vaccine. Groups 2, 3, 4 and 5 received OPV at 7 months, and all infants received OPV at 13 months. Serum immune responses were measured to the primary series at 2 and 7 months and to the booster dose at 12 and 13 months. RESULTS: Reaction rates were similar among groups. In the primary series combining eIPV with DTaP decreased geometric mean titers (GMTs) to diphtheria, tetanus and pertussis. In addition concomitant PRP-T (either simultaneous or combined) with DTaP-eIPV lowered anti-PRP and further decreased tetanus GMTs. Nonetheless in 100% of infants protective titers were achieved against diphtheria and tetanus (>0.01 IU/ml each) and against the poliovirus types 1, 2 and 3 after eIPV (Groups 2 to 5); 99% of infants (Groups 4 and 5) had protective titers against PRP (> or = 0.15 microg/ml). After boosting with DTaP/PRP-T decreased GMTs to diphtheria and PRP antigens were observed in the groups that received DTaP and eIPV combined. Nonetheless protective titers to diphtheria, tetanus and PRP occurred consistently. In contrast concomitant PRP-T with DTaP-eIPV enhanced the pertussis GMTs. CONCLUSIONS: We conclude that combined DTaP, eIPV and PRP-T in a single injection is well-tolerated and elicits an acceptable immune response to each component.

Adhesins, Bacterial↗
PubMed1998

The introduction of routine Haemophilus influenzae type b conjugate vaccine in Chile: a framework for evaluating new vaccines in newly industrializing countries.

OBJECTIVE: To determine the burden of Haemophilus influenzae type b (Hib) disease, the safety and immunogenicity of Hib conjugate vaccine, the practicality of combining Hib conjugate and diphtheria-tetanus-pertussis vaccines and the effectiveness of routine vaccination. STUDY DESIGNS: A series of studies were carried out involving infants and children in Santiago, Chile. The study designs included retrospective surveillance, cost-benefit analysis, randomized placebo-controlled trials of safety and immunogenicity and a Phase IV postlicensure evaluation of vaccine effectiveness. RESULTS: The studies included in this stepwise process showed that Hib invasive disease was a significant public health problem with a substantial economic burden; that combining Hib conjugate and diphtheria-tetanus-pertussis vaccines was practical, safe and elicited a strong immunologic response; and that the combined formulation afforded a high level of protection against invasive Hib disease (90% effectiveness). CONCLUSIONS: In July, 1996, Chile became only the third newly industrializing country to introduce routine Hib conjugate vaccination. New vaccines, such as Hib conjugates, will be more expensive than existing ones. The stepwise process used in Chile may serve as an example for the evaluation of new vaccines in nonindustrialized countries.

Child, Preschool↗
PubMed1998

[Antimicrobial multiresistance of Shigella sp strains in a semi rural community of northern Santiago].

UNLABELLED: Appropriate antimicrobial therapy shortens the duration of Shigellosis and significantly reduces the risk of transmission. Shigella strains resistant to common antimicrobials have increased during the past years, determining the need for a periodic surveillance, to guide effective therapy. AIM: To report the results of a surveillance program in a rural community near Santiago (Colina), for Shigella infections. MATERIAL AND METHODS: Between 1995 and 1997, stool samples from 3,534 episodes of diarrhoea, that occurred in Colina, were obtained. Two hundred twenty six Shigella strains were isolated and studied for susceptibility to ampicilin (AM), amoxicillin/clavulanic acid (AMC), cotrimoxazole (STX), chloramphenicol (CAF), tetracycline (TET), furazolidine (FU), ciprofloxacine (CIPR), nalidixic acid (AC NAL), gentamycin (GENT) and cefotaxime (CFTX). RESULTS: Shigella flexnerii represented 134 of 226 Shigella strains isolated. All strains were susceptible to CIPR, AC NAL, GENT and CFTX. Yearly variation of resistance patterns to other antimicrobials were observed for these strains. Resistance to AM varied from 56 to 76%, to AMC from 25 to 56%, to STX from 21 to 47%, to CAF from 36 to 69%, to TET from 44 to 78% and to FU from 9 to 18%. Overall resistance was higher during 1997. All 85 strains of S sonnei were susceptible to CIPR, AC NAL and CFTX. Resistance throughout the years varied from 56 to 88% for AM, from 0 to 28% for AMC, from 44 to 53% for STX, from 11 to 40% for CAF, from 11 to 42% for TET and from 5 to 11% for FU. Overall resistance was also higher during 1997, except for AM and STX. Seven S hoydii strains were isolated, only during 1995. All seven were resistant to AM and TET and none were resistant to FU, CIPR, AC NAL and CFTX. Two strain was resistant to AMC, STX and CAF. CONCLUSIONS: Antimicrobial resistance patterns of Shigella sp isolated in Colina have increased from 1995 to 1997, specially for commonly used antimicrobials. Resistance remains low for furazolidine and all strains remain susceptible to quinolones.

Child, Preschool↗