Heptavalent Conjugate Vaccine Research Articles

La vigilancia y la evaluación de impacto como estrategias de salud pública: aportes para la introducción de la nueva vacuna cubana contra Streptococcus pneumoniae

Vaccine evaluation studies, based on surveillance data, provide rigorous evidence on the population impact. Beyond the traditional clinical trials, these studies should be part of the evaluation strategy from its conception. Cuba has still not introduced a pneumococcal vaccination; thus a high priority has been given to the development and evaluation of a new heptavalent conjugate vaccine candidate (PCV7-T), which is currently in an advanced phase of clinical evaluation. This paper puts into perspective the value of surveillance and evaluation studies to quantify the effects and impact of the introduction and use of pneumococcal vaccination on invasive and non-invasive disease rates and nasopharyngeal colonisation (carrier status) in infants and pre-school children. The surveillance studies and the ongoing evaluation studies, as well as the main results of the former, are described. The methodological and operational challenges are also addressed. All these elements will contribute to the body of evidence that will support the decision-making on the introduction of the new Cuban vaccine in the National Vaccination Program, and will form the basis for the evaluation of the health impact of the infant population after the introduction of the pneumococcal vaccine in Cuba.

Monitoring and the evaluation of impact as public health strategies: Contributions for the introduction of the new Cuban vaccine against Streptococcus pneumoniae

Vaccine evaluation studies, based on surveillance data, provide rigorous evidence on the population impact. Beyond the traditional clinical trials, these studies should be part of the evaluation strategy from its conception. Cuba has still not introduced a pneumococcal vaccination; thus a high priority has been given to the development and evaluation of a new heptavalent conjugate vaccine candidate (PCV7-T), which is currently in an advanced phase of clinical evaluation. This paper puts into perspective the value of surveillance and evaluation studies to quantify the effects and impact of the introduction and use of pneumococcal vaccination on invasive and non-invasive disease rates and nasopharyngeal colonisation (carrier status) in infants and pre-school children. The surveillance studies and the ongoing evaluation studies, as well as the main results of the former, are described. The methodological and operational challenges are also addressed. All these elements will contribute to the body of evidence that will support the decision-making on the introduction of the new Cuban vaccine in the National Vaccination Programme, and will form the basis for the evaluation of the health impact of the infant population after the introduction of the pneumococcal vaccine in Cuba.

Effectiveness of different vaccine schedules for heptavalent and 13-valent conjugate vaccines against pneumococcal disease in the Community of Madrid.

The heptavalent pneumococcal conjugate vaccine (PCV-7) was added to the childhood routine vaccination program in the Community of Madrid in November of 2006 with 3+1 recommended doses and a catch-up for those under 2years old. In June 2010, PCV-7 was replaced by 13-valent vaccine (PCV-13) with 2+1 recommended doses. In July of 2012, the PCV-13 was removed from the funded program and reintroduced again (2+1 recommended doses) in December 2014. In between, children were vaccinated privately with 3+1 recommended doses of PCV-13. The aim of this study was to evaluate the effectiveness of each vaccination schedule used in the Community of Madrid. We included all cases of invasive pneumococcal disease (IPD) reported between 2007 and 2015 to the Notifiable Diseases Surveillance System. Vaccination information was obtained from the Immunization Registry. Vaccine effectiveness (VE) was estimated using the indirect cohort design for cases with serotype information. A total 779 cases were included in the study. Among them 47.6% of the cases were primo-vaccinated with booster, 20% primo-vaccinated, 15.9% incompletely primo-vaccinated and 16.5% not vaccinated. The VE for ≥1 doses of any PCV was 82% (CI 95%: 67.8-89.9%): 91.9% (CI 95%: 76.5-97.2%) for PCV-7 and 77.2% (48.6-89.9%) for PCV-13. VE in those receiving the full 2+1 or 3+1 schedules was 100% for both vaccines. A high number of vaccine failures were reported in children before they had the opportunity to receive the booster dose, especially due to PCV-13-non-PCV-7 serotypes. VE was higher for PCV-7 compared to PCV-13, except for those that received the complete schedule with booster that achieved 100% of VE, which shows the relevance of the vaccines and complying with all doses scheduled.

Influence of the Co-Administration of Heptavalent Conjugate Vaccine PCV7-TT on the Immunological Response Elicited by VA-MENGOC-BC® and Heberpenta®-L in Rabbits

ABSTRACTFinlay Vaccine Institute is developing a new heptavalent conjugate vaccine against Streptococcus pneumoniae. As infants are the target population, PCV7-TT will be necessarily co-administered with other vaccines, and then, the interactions represent a concern. The aim of this work is to evaluate the possible immunological interferences in rabbits as animal experimental model. Rabbits were immunized with Heberpenta®-L, VA-MENGOC-BC®, and PCV7-TT. Blood samples were taken fourteen days after final immunization for obtaining sera. Antibody responses to all antigens were evaluated by indirect ELISA. Functional responses against diphtheria and tetanus toxoid were done by in vivo seroneutralization assay. No interference was observed by PCV7-TT over the humoral response against diphtheria toxoid and meningococcal antigens (p > 0.05). A nonstatistically significant reduction (p > 0.05) was observed in the case of the humoral response against Haemophilus influenzae type b oligosaccharide. Concomitant administration of Heberpenta®-L and PCV7-TT increased twice the antibody titers as well as the protective activity against tetanus toxoid, but no statistical differences were found. The co-administration did not induce a reduction in the percent of responders against pneumococcal polysaccharides contained in PCV7-TT vaccine. Concomitant administration of PCV7-TT did not induce interferences over the evaluated antigens of Heberpenta®-L and VA-MENGOC-BC®. Also, no interference was observed on the immune response elicited by PCV7-TT. These preclinical results suggest that PCV7-TT will not result in a serious problem over the immune response elicited by the licensed vaccines Heberpenta®-L and VA-MENGOC-BC®. However, the clinical interference could be strictly studied during clinical trials in infants.

Impact of the Pneumococcal Heptavalent Conjugated Vaccine on <i>Streptococcus pneumoniae</i> Nasopharyngeal Carriage and Antimicrobial Susceptibility in Children 2-5-Year-Old in Beijing, China

Streptococcus pneumoniae is a primary cause of illness and death among children younger than 5 years in China. The heptavalent pneumococcal conjugate vaccine (PCV7) was the only conjugated vaccine (PCV) available in China from 2008 to 2013. This randomized, controlled, open-label study conducted at 46 Beijing clinics involved 3281 healthy 2-5-year-old Chinese children, randomized 1:1 to receive one dose of the S. pneumoniae heptavalent conjugated vaccine (PCV7) (n = 1643) or Haemophilus influenzae type b conjugate vaccine (Hib) (n = 1638). The main objective of this study was to investigate the impact of PCV7 against that of Hib vaccination in the nasopharyngeal S. pneumoniae colonization in healthy Chinese children. Nasopharyngeal (NP) samples for culture, serotyping and antimicrobial susceptibility testing were collected before vaccination and at Day 60 and 180 post-vaccination. A total 3281 children were enrolled in the study. Demographic characteristics were similar among both study groups: 1641 children received PCV7. Before immunization, S. pneumoniae was isolated in 338 and 360 children in the PCV7 (144 PCV7 isolates) and Hib groups (145 PCV7 isolates), respectively. At Day 180, PCV7 vaccination was more effective than Hib vaccination in reduction NP carriage (20.2% [P = 0.052]) and new acquisition (19.0% [P = 0.066]). When reductions in NP carriage and new acquisition of PCV7 VT plus 6A was analyzed, reduction in the PCV7 vaccinated group achieved statistical significance (P = 0.034 and P = 0.042 versus Hib, respectively). NP carriage of NVT increased in both groups (P = 0.305 between study groups at Day 180). PCV7 decreased NP carriage of non-susceptible VT to amoxicillin (P = 0.000), ceftriaxone (P = 0.047) and MDR (P = 0.024) versus Hib. PCV7 vaccination in Chinese children 2 to 5 years of age was more effective than vaccination with Hib in the reduction of S. pneumoniae nasopharyngeal carriage, new acquisition and non-susceptible isolates.

Characterization of Streptococcus pneumoniae clones from paediatric patients with cystic fibrosis.

The role of Streptococcus pneumoniae in cystic fibrosis (CF) is poorly understood. The pneumococcal population has changed over time after the introduction of the heptavalent conjugate vaccine (PCV7) and, more recently, the 13-valent conjugate vaccine (PCV13). Although serotypes and clones causing invasive pneumococcal disease or colonizing healthy children have been extensively analysed, little is known so far on the serotypes and clones of pneumococci in CF patients. The aim of this work was to investigate serotypes, antibiotic susceptibilities, genotypes and biofilm production of CF pneumococcal isolates. Overall, 44 S. pneumoniae strains collected from 32 paediatric CF patients from January 2010 to May 2012 in a large Italian CF Centre were tested for antimicrobial susceptibility testing by Etest, serotyped by the Quellung reaction and genotyped by a combination of different molecular typing methods, including pbp gene restriction profiling, pspA restriction profiling and sequencing, PFGE and multilocus sequence typing. Biofilm production by pneumococcal strains was also assessed. Penicillin non-susceptibility was 16 %. High resistance rates (>56 %) were observed for erythromycin, clindamycin and tetracycline. The most frequent serotype recovered was serotype 3 (31.8 %). The coverage of PCV7 and PCV13 was 6.8 and 47.7 %, respectively. More than 80 % of CF strains belonged to Pneumococcal Molecular Epidemiology Network (PMEN) reference clones, the most common being Netherlands(3)-ST180 (28.2 %), and Greece(21)-30/ST193 (15.4 %). All strains produced biofilm in vitro, although with large variability in biofilm formation efficiency. No correlation was found between biofilm levels and serotype, clone or antibiotic resistance. The high isolation rate of antibiotic-resistant serotype 3 pneumococci from CF patients suggests that PCV13 could increase protection from pneumococcal colonization and infection.

Safety and preliminary immunogenicity of Cuban pneumococcal conjugate vaccine candidate in healthy children: A randomized phase I clinical trial

A new heptavalent conjugate vaccine (PCV7-TT) is under development in Cuba. PCV7-TT contains 2μg of serotypes 1, 5, 14, 18C, 19F, 23F and 4μg of 6B, each one conjugated to tetanus toxoid (TT). This vaccine was designed with the serotypes that cause most invasive pneumococcal diseases (IPD) worldwide. In the present study, we investigated the safety and explored the immunogenicity of PCV7-TT during a controlled, randomized and double blind clinical trial phase I in 4–5-year-old children. PCV7-TT was well tolerated and as safe as Synflorix used as control vaccine. Following a single-dose vaccination, all individual serotypes included in PCV7-TT induced statistically significant increase of IgG GMC and OPA GMT. These are the first clinical results of PCV7-TT in children and they pave the way toward next clinical trials in children and infants. This clinical trial was published in the Cuban Public Register of Clinical Trials with code RPCEC00000173.

Evidence for soft selective sweeps in the evolution of pneumococcal multidrug resistance and vaccine escape.

The multidrug-resistant Streptococcus pneumoniae Taiwan19F-14, or PMEN14, clone was first observed with a 19F serotype, which is targeted by the heptavalent polysaccharide conjugate vaccine (PCV7). However, “vaccine escape” PMEN14 isolates with a 19A serotype became an increasingly important cause of disease post-PCV7. Whole genome sequencing was used to characterize the recent evolution of 173 pneumococci of, or related to, PMEN14. This suggested that PMEN14 is a single lineage that originated in the late 1980s in parallel with the acquisition of multiple resistances by close relatives. One of the four detected serotype switches to 19A generated representatives of the sequence type (ST) 320 isolates that have been highly successful post-PCV7. A second produced an ST236 19A genotype with reduced resistance to β-lactams owing to alteration of pbp1a and pbp2x sequences through the same recombination that caused the change in serotype. A third, which generated a mosaic capsule biosynthesis locus, resulted in serotype 19A ST271 isolates. The rapid diversification through homologous recombination seen in the global collection was similarly observed in the absence of vaccination in a set of isolates from the Maela refugee camp in Thailand, a collection that also allowed variation to be observed within carriage through longitudinal sampling. This suggests that some pneumococcal genotypes generate a pool of standing variation that is sufficiently extensive to result in “soft” selective sweeps: The emergence of multiple mutants in parallel upon a change in selection pressure, such as vaccine introduction. The subsequent competition between these mutants makes this phenomenon difficult to detect without deep sampling of individual lineages.

Immunogenicity of Heptavalent Conjugate Vaccine Against Streptococcus pneumoniae in Premature Babies with Low Birth Weight

There are few studies about immunogenicity and safety of heptavalent pneumococcal-CRM197 conjugate vaccine (PCV7) in low birth weight infants. Assessment of immunogenicity following administration of PCV7 in low birth weight children. The PCV7 vaccine was administered to 60 infants divided into two groups: 23 children with birth weight <1000g (Group I); and 37 children with birth weight ≥1000g (Group II). Serum was collected four times. Birth weight of children included in the study ranged from 480g to 2450g. The primary immunization caused an increase in the average concentration of antibodies for all serotypes in most of the participants, with no significant differences between the groups. However, there were some differences between various serotypes. Group serotypes 6B and 23F were the least immunogenic (≥0.35μg/mL, Group I vs. Group II - 6B: 78.3% vs. 67,6% p=0.371 and 23F: 87% vs. 83.8% p=0.738). Prior to the administration of a booster dose, a significant decrease in antibody titer was observed in all children. The last vaccination resulted in an increased concentration of antibodies in all children in both groups, and the results were significantly higher compared to those measured following administration of three doses of the vaccine. PCV7 is immunogenic in children with low, very low, and extremely low birth weight. Serotypes 6B and 23F were the least immunogenic, and serotype 14 proved to be the most immunogenic.

Changes in Streptococcus pneumoniae serotype distribution in invasive disease and nasopharyngeal carriage after the heptavalent pneumococcal conjugate vaccine introduction in Bogotá, Colombia

BackgroundIn Bogotá, the Heptavalent Conjugate Vaccine (PCV7) was introduced into childhood immunization schedule since 2009. The aim of this study was to assess the changes in serotype distribution and penicillin susceptibility of Streptococcus pneumoniae isolates recovered from nasopharyngeal samples and invasive disease among children living in Bogotá, before and after PCV7 introduction. MethodsNasopharyngeal swabs were collected from healthy children aged between 12 and 18 months of age before (years 2005–2006) and after (2011) PCV7 introduction. Identification of S. pneumoniae was performed by multiplex PCR. Serotype was determined by PCR and Quellung reaction. Susceptibility to penicillin, ceftriaxone, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline and erythromycin was evaluated. In addition, distribution of serotypes and antimicrobial susceptibility before and after vaccine introduction among invasive isolates recovered from children ≤2 years old living in Bogotá was analyzed. ResultsPrevalence of pneumococcal nasopharyngeal carriage declined from 55.7% (137/246) in unvaccinated to 44.2% (87/197) (p=0.01) in vaccinated children. The proportion of children carrying PCV7 serotypes decreased from 23.6% (58/246) to 7.6% (15/197) (p<0.001). The decrease was counterbalanced by an increase in the proportion of non-PCV7 serotypes. The most prevalent among emerging serotypes were 15A, 15B, 15C, 11A and 35B. Among IPD isolates, PCV7 serotypes decreased from 69.1% (235/340) in 2005/2009 to 38.0% (32/84) in 2010/2011 (p<0.001). The increase of non-PCV7 serotypes was significant. Resistance to penicillin among invasive isolates recovered from meningitis decreased from 41.1% (30/73) in the pre-vaccine period to 14.2% (2/14) in post-vaccine period (p=0.02). ConclusionsA decrease in the prevalence of pneumococcal nasopharyngeal carriage following the introduction of PCV7 vaccine, have been overshadowed by an important surge in the prevalence of non-PCV7 serotypes. Systematic surveillance combining nasopharyngeal carriage surveys and IPD detection could help in evaluating the impact of conjugate vaccines.

A Case Report; Purulent Meningitis Due to Serotype 2 of Streptococcus pneumoniae

: Children under 2 years of age suffer from some of the highest rates of invasive pneumococcal disease (IPD) in the world. (Turkey) Rates of IPD had a decline after statewide introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2008. Introduction of PCV7, PCV10 and PCV13 vaccines resulted in elimination of IPD caused by vaccine serotypes, but was followed by increasing rates of IPD caused by nonvaccine serotypes. Although the heptavalent vaccine has demonstrated its ability to reduce the incidence of pneumococcal disease, its efficacy is limited due to the restricted number of serotypes included. We report a case involving a 3-month-old girl who developed meningitis with Streptococcus pneumoniae serotype 2 despite the use of heptavalent conjugate vaccine.

Pneumococcal infections in oncohematological patients after the introduction of conjugate vaccine

ObjectivesTo know the symptoms and predominant serotypes of pneumococcal infection in patients with oncohematological illness after introduction of 7-valent pneumococcal conjugate vaccine. Patients and methodsA prospective study (January 2006–May 2011) was made for all the incident cases of infection in oncohematological patients over 17 years of age in whom Streptococcus pneumoniae was isolated. ResultsA total of 131 episodes of incident cases of pneumococcal infection in 122 patients (median age of 67 years) were detected. Of these, 50% were related to health/nosocomial care (p<.001), 39.7% to pneumonias and 45.1% to lower respiratory tract infections, without radiological condensation. In comparison of the 803 incident cases of pneumococcal infection during the same period with patients without oncohematological disease, the oncohematological patients were more frequently males (p<.001), who had pneumonia episodes with higher FINE scores (p<.001), lower risk of death non-directly associated with pneumococcal infection (p=.006) and showed reduced susceptibility to levofloxacin (p=.043). Non-vaccine serotypes predominated. ConclusionsPneumococcal infections in oncohematological patients are more frequent in males, mainly with lung neoplasms. They are heath care related, but not related to chemotherapy or neutropenia. After the introduction of heptavalent conjugate vaccines in pediatrics, the non-vaccine serotypes predominate.

Incidence of pneumococcal infections among children under 15 years in southern Catalonia throughout the heptavalent conjugate vaccine era, 2002–2009

Updating epidemiological studies to document current incidences of pneumococcal diseases are greatly needed in the current era of new pneumococcal conjugate vaccines (PCVs). The aim of this study is to analyze the incidence and distribution of different serotypes causing pneumococcal infections among the pediatric population in southern Catalonia, Spain, throughout the 2002-2009 PCV7 eras. A population-based surveillance study was conducted among children aged ≤ 14 years in the region of Tarragona (Catalonia, Spain) during the period 2002-2009. All cases of pneumococcal infections (invasive and non-invasive cases) were included in the study. Incidence rates (per 100,000 population-year) and prevalence of infections caused by serotypes included in different PCV formulations were calculated for the 2002-2005 and 2006-2009 periods. Globally, across the total 2002-2009 period, the incidence of pneumococcal infections was 48.2 per 100,000 children-year (22.4 and 25.8 for invasive and non-invasive infections, respectively). Between 2002-2005 and 2006-2009, the incidence rates largely decreased among children aged <2 years (from 171 to 111 per 100,000 children-year; p = 0.059), but they did not substantially vary among children aged 2-14 years. The percentages of cases caused by serotypes included in PCV7 (60.0 vs. 16.7 %; p < 0.001), PCV10 (75.0 vs. 47.4 %; p = 0.028), and PCV13 (85.0 vs. 70.5 %; p = 0.190) decreased in both periods. In this study, which was conducted in a setting with intermediate PCV7 uptakes, a considerable protective direct effect of vaccination occurred among young infants, but an indirect protective effect did not emerge in the rest of the pediatric population. Despite new PCVs with higher serotype coverage, an important proportion of pneumococcal infections is still not covered by these vaccines.

Infección neumocócica en pacientes oncohematológicos tras la introducción de la vacuna conjugada

ObjectivesTo know the symptoms and predominant serotypes of pneumococcal infection in patients with oncohematological illness after introduction of 7-valent pneumococcal conjugate vaccine. Patients and methodsA prospective study (january 2006-may 2011) was made of all the incident cases of infection in oncohematological patients over 17 years of age in whom Streptococcus pneumoniae was isolated. ResultsA total of 131 episodes of incident cases of pneumococcal infection in 122 patients (median age of 67 years) were detected. Of these, 50% were related to health/nosocomial care (P<.001), 39.7% pneumonias and 45.1% lower respiratory tract infections, without radiological condensation. In comparison to the 803 incident cases of pneumococcal infection during the same period as in patients without oncohematological disease, the oncohematological patients were more frequently males (P<.001), had pneumonia episodes with higher FINE scores (P<.001), lower risk of death non-directly associated with pneumococcal infection (P=.006) and showed reduced susceptibility to levofloxacin (P=.043). Non-vaccine serotypes predominated. ConclusionsPneumococcal infections in oncohematological patients are more frequent in males, mainly with lung neoplasms. They are heath care related, but not related to chemotherapy or neutropenia. After the introduction of heptavalent conjugate vaccines in pediatrics, the non-vaccine serotypes predominate.

Pneumococcal Bacteremia in a Vaccinated Pediatric Sickle Cell Disease Population

The incidence of pneumococcal disease in sickle cell disease declined significantly with penicillin prophylaxis as well as with the pneumococcal polysaccharide and heptavalent conjugate vaccines. In this report, we describe our experience with pneumococcal bacteremia in pediatric patients with sickle cell disease in the post-heptavalent pneumococcal conjugate vaccine era. Despite established prophylactic strategies, pneumococcal bacteremia continues to occur in patients with sickle cell disease.

Clinical Presentation of Invasive Pneumococcal Disease in Spain in the Era of Heptavalent Conjugate Vaccine

The aim of this study was to analyze the rate of incidence, clinical presentation, serotype, and clonal distribution of invasive pneumococcal disease (IPD) in the era of heptavalent pneumococcal conjugate vaccine (PCV7) in Barcelona, Spain. This was a prospective study comprising all children <5 years with IPD who were managed in 2 tertiary-care, pediatric hospitals between January 2007 and December 2009. IPD was defined as the presence of clinical findings of infection together with isolation or detection of DNA of Streptococcus pneumoniae in a sterile fluid sample. In this study, 319 patients (53.3% male), mean age 29.6 months, were included. Comparing rates in 2007 and 2009 (76.2 and 109.9 episodes/100,000 population, respectively), an increase of 44% (95% confidence interval, 10%-89%) was observed. The main clinical presentation was pneumonia (254 episodes, 79.6%), followed by meningitis (29, 9.1%), and bacteremia (25, 7.8%).The diagnosis was made by positive culture in 123 (38.6%) patients and in 196 (61.4%) by real-time polymerase chain reaction. Serotype study was performed in 300 episodes, and 273 (91%) were non-PCV7 serotypes. The most frequent serotypes were 1 (20.7%), 19A (15.7%), and 3 (12.3%). A minimal inhibitory concentration ≥0.12 μg/mL to penicillin was detected in 34.4% of isolates. Sequence type 306 expressing serotype 1 was the most frequent clonal type detected (20.3% of studied strains). IPD continues to increase in Barcelona, and the rate is higher than previously reported as a result of low sensitivity of bacterial culture. Non-PCV7 serotypes were responsible for 91% of episodes and pneumonia was the main clinical presentation.

Complicated Pneumococcal Meningitis in a Fully Vaccinated Child: Value of Magnetic Resonance Imaging Monitoring

We present a unique case of life-threatening pneumococcal meningitis complicated by vasculitis in a fully vaccinated 4-year-old female with the heptavalent conjugate vaccine for Streptococcus pneumoniae (PCV7). Serotype 23F was isolated in both blood and cerebral spinal fluid (CSF) samples. Pulses of methylprednisolone were promptly initiated in addition to antibiotics leading to a good recovery. CSF studies and magnetic resonance imaging (MRI) of the brain were used for diagnosis and monitoring the response to corticoid therapy. We report the investigations of a child with failure of PCV7 vaccine to protect against vaccine-serotype invasive disease. Use of corticosteroids and temporal association with changes in brain imaging are described for the first time in literature.

Incidence of invasive pneumococcal disease among elderly people in Southern Catalonia, Spain, 2002–2009: An increase in serotypes not contained in the heptavalent conjugate vaccine

Population-based surveillance study conducted among persons ≥ 65 years old in Southern Catalonia, Spain during 2002-2009. All cases with isolation of pneumococcus from normally sterile bodily fluids were included. Incidence rates of invasive pneumococcal disease (IPD) as well as rates of infections caused by serotypes included in the heptavalent pneumococcal conjugate vaccine (PCV7) and the 23-valent polysaccharide pneumococcal vaccine (PPV23) were compared for early (2002-2005) and contemporary (2006-2009) periods. Mean incidence rate (per 100,000 population-year) of IPD across study period was 48.0 [95% CI (confidence interval): 30.1-72.5]. Incidence rates for PCV7 serotypes slightly decreased by 21% between 2002-2005 and 2006-2009 (from 9.2 to 7.3; p = 0.511) whereas rates of IPD due to nonPCV7 serotypes largely increased by 172% (from 15.6 to 42.4; p < 0.001) during the same period. For PPV23 but nonPCV7 types, incidence rates increased by 146% (from 10.9 to 26.9; p < 0.001) whereas rates for nonPPV23 serotypes increased by 237% (from 4.6 to 15.5; p = 0.001). As an overall effect of these changes, the incidence of all IPD increased by a significant 69% (95% CI: 29%-110%). Specific incidence rates of serotypes 6A (from 1.7 to 4.1; p = 0.182), 7F (from 1.7 to 5.7; p = 0.052) and 19A (from 0.6 to 6.2; p = 0.004) substantially increased between both periods. According to these findings, Southern Catalonia region can be classified as a mesoendemic area of pneumococcal infections among elderly people, with a recent increase incidence of some nonPCV7 serotypes (especially 19A).

Immunogenicity and safety of heptavalent conjugate vaccine against Streptococcus pneumoniae in pre-term Polish infants

The purpose of the study was to assess post-vaccination immune response and occurrence of adverse events in the group of prematurely born infants. The study included 40 pre-term infants. Each child was vaccined four times (2, 4, 6 and 16 months) with the heptavalent conjugated pneumococcal vaccine (PCV7). Assessing of the level of antibodies was performed before vaccination, 4 weeks after primary series, before and 4 weeks after the booster dose. The research participants were qualified into 2 groups: group I – 19 children born before 30th gestational week, group II – 21 children born between the 30th and 34th gestational week. After the basic vaccination, an increase in the average antibody concentration in the area of all serotypes in most of the children tested was registered, with no significant differences observed between the groups. However, differences between individual serotypes were observed. The lowest values were found for serotype 6B. Before administering the booster dose, a significant drop in antibody titre in all of the children tested was noted. The last vaccination caused another significant increase in antibody concentration in both groups and the results obtained were markedly higher than those obtained after administering three vaccine doses. The majority of the children tested (with the exception of three from group II) achieved the preventive antibody level ≥0.35 μg/ml. In all of the children, no serious adverse events were observed. Our research showed, that heptavalent pneumococcal conjugate vaccine is immunogenic in children born before the completion of the 34th week of pregnancy. A booster dose of vaccine must be given at the right time to optimal response to the vaccine for all serotypes. Finally, any serious adverse events were observed.

Bacterial Meningitis in the U.S.: An Update

Pediatric immunization programs that include the Haemophilus influenzae type B and heptavalent protein-polysaccharide pneumococcal conjugate vaccines