A randomized, controlled trial comparing the immunogenecity and safety of a 23-valent pneumococcal polysaccharide vaccination to a repeated dose 13-valent pneumococcal conjugate vaccination in kidney transplant recipients.

BACKGROUND: The risk of invasive pneumococcal disease is significant among solid organ transplant (SOT) recipients. The optimal pneumococcal vaccination strategy for SOT patients is not known. METHODS: The potential kidney transplant recipients in dialysis were randomized into two arms: to receive a 23-valent pneumococcal polysaccharide vaccine (PPV23) before transplantation or to receive a 13-valent pneumococcal conjugate vaccine (PCV13) before transplantation and a second dose of PCV13 six months after the transplantation. Serotype-specific antibody concentrations and opsonophagocytic activity (OPA) were measured before and after the first vaccination (visits V1,V2) and six and seven months after the transplantation, for example, before and after the second PCV13 (visits V3,V4). RESULTS: Out of 133 participants, 48 (PCV13 arm) and 46 (PPV23 arm) received a kidney transplant, and 37 + 37 in both arms completed the study. After the first vaccination, the geometric mean concentrations (GMCs) in the PCV13 arm were significantly higher for 9/13 serotypes and the OPA geometric mean titers (GMTs) were significantly higher for 4/13 serotypes. At V3, the antibody levels had declined but OPA remained significantly higher for 7/13 (PCV13) vs 4/13 (PPV23) serotypes. At V4, the GMCs for 9/13 serotypes and the GMTs for 12/13 serotypes were significantly higher in the PCV13 arm. The GMCs but not GMTs were lower than at V2. There was no difference in adverse effects. No vaccine-related allograft rejection was detected. CONCLUSIONS: The immunogenicity of PCV13 was better in dialysis patients, and revaccination with PCV13 was immunogenic and safe.

Coadministered pneumococcal conjugate vaccine decreases immune response to hepatitis A vaccine: a randomized controlled trial.

OBJECTIVES: We explored the influence of coadministration on safety and immunogenicity of the most common travellers' vaccine hepatitis A (HepA) and the pneumococcal conjugate vaccine (PCV) increasingly used both at home and before travel. METHODS: Volunteers aged ≥18 years (n = 305) were randomly assigned 1:1:1 into three groups receiving: 13-valent PCV (PCV13) + HepA, PCV13, or HepA. Anti-pneumococcal IgG concentrations, opsonophagocytic activity (OPA) titres, and total hepatitis A antibody (anti-HAV) concentrations were measured before and 28 ± 3 days after vaccination. Adverse events (AEs) were recorded over 4 weeks. RESULTS: After vaccination, the anti-HAV geometric mean concentration was significantly lower in the PCV13+HepA than the HepA group: 34.47 mIU/mL (95% CI: 26.42-44.97 mIU/mL) versus 72.94 mIU/mL (95% CI: 55.01-96.72 mIU/mL), p < 0.001. Anti-HAV ≥10 mIU/mL considered protective was reached by 71 of 85 (83.5%) in the PCV13+HepA group versus 76 of 79 (96.2%) in the HepA group, p 0.008. The increases in anti-pneumococcal IgG and OPA levels were comparable in the PCV13+HepA and PCV13 groups, apart from a bigger rise in the PCV13+HepA group for serotype 3 (one-way ANOVA: serotype 3 IgG p 0.010, OPA p 0.002). AEs proved more frequent among those receiving PCV13 than HepA, but simultaneous administration did not increase the rates: ≥one AE was reported by 45 of 56 (80.4%) PCV13, 43 of 54 (79.6%) PCV13+HepA, and 25 of 53 (47.2%) HepA recipients providing structured AE data. DISCUSSION: Coadministration of HepA and PCV13 did not cause safety concerns, nor did it impact the patients' response to PCV13, apart from serotype 3. However, coadministered PCV13 significantly impaired antibody responses to HepA.

Genotypic and phenotypic characterization of carriage and invasive disease isolates of Neisseria meningitidis in Finland.

The relationship between carriage and the development of invasive meningococcal disease is not fully understood. We investigated the changes in meningococcal carriage in 892 military recruits in Finland during a nonepidemic period (July 2004 to January 2006) and characterized all of the oropharyngeal meningococcal isolates obtained (n = 215) by using phenotypic (serogrouping and serotyping) and genotypic (porA typing and multilocus sequence typing) methods. For comparison, 84 invasive meningococcal disease strains isolated in Finland between January 2004 and February 2006 were also analyzed. The rate of meningococcal carriage was significantly higher at the end of military service than on arrival (18% versus 2.2%; P < 0.001). Seventy-four percent of serogroupable carriage isolates belonged to serogroup B, and 24% belonged to serogroup Y. Most carriage isolates belonged to the carriage-associated ST-60 clonal complex. However, 21.5% belonged to the hyperinvasive ST-41/44 clonal complex. Isolates belonging to the ST-23 clonal complex were cultured more often from oropharyngeal samples taken during the acute phase of respiratory infection than from samples taken at health examinations at the beginning and end of military service (odds ratio [OR], 6.7; 95% confidence interval [95% CI], 2.7 to 16.4). The ST-32 clonal complex was associated with meningococcal disease (OR, 17.8; 95% CI, 3.8 to 81.2), while the ST-60 clonal complex was associated with carriage (OR, 10.7; 95% CI, 3.3 to 35.2). These findings point to the importance of meningococcal vaccination for military recruits and also to the need for an efficacious vaccine against serogroup B isolates.

Immunity after (re)vaccination of paediatric patients following haematopoietic stem cell transplantation.

AIMS: Loss of specific immunity follows allogeneic haematopoietic stem cell transplantation (HSCT) in the majority of cases. Responses to (re)vaccinations can be used as indicators of a functional immunological recovery. METHODS: Twenty-three paediatric recipients of HSCT were enrolled in a single centre setting and responses to scheduled immunizations analysed. RESULTS: Immunity to vaccine-preventable diseases was impaired post HSCT, but (re)vaccinations induced protective responses in 59-100%, depending on the vaccine, regardless of prior graft-versus-host disease (GVHD) history. CONCLUSION: Despite the marked impact of moderate to severe chronic prior GVHD on both the qualitative and quantitative T-cell recovery post allogenic HSCT, most paediatric recipients of allogeneic stem cell grafts appear to attain protective antibody levels after immunization.

Effect of HIV infection status and anti-retroviral treatment on quantitative and qualitative antibody responses to pneumococcal conjugate vaccine in infants.

Serotype-specific antibody concentration and opsonophagocytic activity (OPA) were evaluated after 3 doses of pneumococcal conjugate vaccine. Groups included human immunodeficiency virus (HIV)-positive infants with CD4(+) cell percentages > or =25% who initiated immediate antiretroviral treatment (the HIV+/ART+ group) or whose antiretroviral treatment was deferred until clinically or immunologically indicated (the HIV+/ART- group). Immune responses were also evaluated in HIV-noninfected infants born to HIV-seronegative (M-/I-) or HIV-positive mothers (M+/I-). Antibody concentrations were similar between HIV+/ART+ and HIV+/ART- infants. However, antibody concentrations were lower in M-/I- infants than in M+/I- infants. Nevertheless, M-/I- infants had superior OPA responses, compared with those in HIV+/ART+ infants, who in turn had better OPA responses, compared with those in HIV+/ART- infants.

A randomized, controlled trial comparing the immunogenicity and safety of a 23-valent pneumococcal polysaccharide vaccination to a repeated dose 13-valent pneumococcal conjugate vaccination in adult liver transplant recipients.

BACKGROUND: Solid organ transplant (SOT) patients are at significant risk for invasive pneumococcal disease. The optimal pneumococcal vaccination strategy for SOT patients is not known. METHODS: The potential adult liver transplant recipients were randomised into two arms: to receive a 23-valent pneumococcal polysaccharide vaccine (PPV23) before the transplantation or to receive a 13-valent pneumococcal conjugate vaccine (PCV13) before the transplantation and a second dose of PCV13 six months after the transplantation. Serotype-specific antibody concentrations and opsonophagocytic activity (OPA) were measured before and after the first vaccination (visits V1,V2) and six and seven months after the transplantation, e.g. before and after the second PCV13 (visits V3,V4). RESULTS: Out of 47 patients, 19 (PCV13 arm) and 17 (PPV23 arm) received a liver transplant and all these patients completed the study (36/47, 76,6%). Each vaccine schedule elicited a good immune response. At V2, the geometric mean concentrations (GMCs) of antibodies for serotypes 6A, 7F and 23F, and the geometric mean titers (GMT́s) of OPA for serotypes 4, 6A, 6B and 23F were significantly higher for PCV13, but the proportions of patients reaching OPA cut-off ≥ 8 or ELISA cut-off ≥ 1.0 µg/ml did not differ between the arms. At V3 the antibody concentrations and the OPA had declined to baseline in both arms. The second PCV13 vaccination elicited an immune response. There was no difference in adverse events. No vaccine-related allograft rejection was detected. CONCLUSIONS: The immunogenicity of PPV23 and PCV13 was comparable in this patient material, but the seroresponses waned after transplantation. The second dose of PCV13 restored the immune responses and was well tolerated.

The capsular serotype of Streptococcus pneumoniae is more important than the genetic background for resistance to complement.

The polysaccharide capsule of Streptococcus pneumoniae inhibits phagocytic killing by innate immune mechanisms. Certain serotypes are associated with invasive disease while others with a nasopharyngeal carriage. The invasiveness of serotypes may partly be explained by ability to resist deposition of complement (C3) on the bacterial surface and consequent opsonophagocytic killing. In our previous studies, we observed that clinical isolates of serotypes 1 and 5, which are rarely detected in asymptomatic carriage, were resistant to complement deposition and opsonophagocytosis, whereas serotypes 6B and 23F, both common in carriage, were more sensitive to deposition of C3 and opsonophagocytic killing. However, presence of significant variation in C3 deposition between isolates of the same serotype indicated that factors other than the capsule also affect complement resistance. To distinguish the relative effect of the capsular serotype and other virulence factors on C3 deposition, we compared capsule-switched mutants prepared in genetic backgrounds of pneumococcal strains TIGR4, 603, and 618. Clinical isolates which had the same multilocus sequence type but expressed different serotypes were also compared. We found that the serotype had a significant impact on complement resistance and that the more resistant the strain was to complement, the higher was the concentration of polysaccharide-specific antibodies required for opsonophagocytic killing. Comparison of strains expressing the same capsular polysaccharides in the different genetic backgrounds and various capsular mutants of the same strain suggests that while the genotype affects complement resistance, the serotype is the most important determinant. Differences between serotypes were more significant than the differences between strains.

Serotype-related variation in susceptibility to complement deposition and opsonophagocytosis among clinical isolates of Streptococcus pneumoniae.

The polysaccharide capsule is a major virulence factor of Streptococcus pneumoniae; it affects complement resistance and shields the bacterium from phagocytes. Certain capsular serotypes appear to be better able to cause invasive disease than others. Serotypes 1 and 5 are common causes of invasive disease but are rarely isolated from healthy carriers, whereas serotypes 6B and 23F are more frequently isolated from carriage than invasive disease. We have recently shown that serotypes 6B and 19F differ in resistance to complement C3 deposition and opsonophagocytic killing. In this study we assessed the complement resistance and susceptibility to opsonophagocytosis of several other serotypes targeted by the pneumococcal conjugate vaccines. Clinical isolates of serotypes 1, 4, 5, 14, 18C, and 23F were tested along reference strains of corresponding capsular types. The concentration of anticapsular antibodies required for opsonophagocytic killing correlated inversely with C3 deposition on the serotype. Serotype 1 was the most resistant of the clinical isolates to C3 deposition and, along with serotypes 5 and 19F, required the highest concentration of capsule antibodies for opsonophagocytic killing, whereas serotype 23F was the most sensitive to opsonophagocytosis. Sensitivity to C3 deposition and opsonophagocytosis was associated with serotype-specific mortality of invasive pneumococcal disease, suggesting that the primary pathogens, such as serotypes 1 and 5, are more resistant to complement and require a higher concentration of capsule antibodies for opsonophagocytic killing than the opportunistic serotypes such as 6B and 23F, which are associated with a more severe disease outcome.

Interaction of pneumococcal histidine triad proteins with human complement.

The pneumococcal histidine triad (Pht) proteins PhtA, PhtB, PhtD, and PhtE form a group of conserved pneumococcal surface proteins. Humans produce antibodies to Pht proteins upon exposure to pneumococcus, and immunization of mice has provided protective immunity against sepsis and pneumonia and reduced nasopharyngeal colonization. Pht proteins are candidates for inclusion in multicomponent pneumococcal protein vaccines. Their biological function in pneumococcal infections is not clear, but a role in complement inhibition has been suggested. We measured complement deposition on wild-type and Pht mutant strains in four genetic backgrounds: Streptococcus pneumoniae D39 (serotype 2) and R36A (unencapsulated derivative of D39) and strains of serotypes 3, 4, and 19F. PspA and PspC single and double mutants were compared to the wild-type and Pht-deficient D39 strains. Factor H binding was measured to bacterial cells, lysates, and protein antigens. Deletion of all four Pht proteins (Pht(-)) resulted in increased C3 deposition on the serotype 4 strain but not on the other strains. Pht antigens did not bind factor H, and deletion of Pht proteins did not affect factor H binding by bacterial lysates. The Pht(-) mutant serotype 4 strain bound slightly less factor H than the wild-type strain when binding was measured by flow cytometry. Pht proteins may play a role in immune evasion, but the mechanism of function is unlikely to be mediated by factor H binding. The relative contribution of Pht proteins to the inhibition of complement deposition is likely to be affected by the presence of other pneumococcal proteins and to depend on the genetic background.

Serotype-specific hyporesponsiveness to pneumococcal conjugate vaccine in infants carrying pneumococcus at the time of vaccination.

OBJECTIVE: To determine whether pneumococcal carriage at the time of 11-valent pneumococcal conjugate vaccine (PCV-11) administration interferes with immune response in infants. STUDY DESIGN: A total of 1111 Filipino infants recruited into an immunogenicity and carriage study, nested in an efficacy trial, received PCV-11 or saline solution placebo at 6, 10, and 14 weeks of age. Antibody concentrations to the most frequently carried vaccine serotypes 6B, 19F, and 23F were measured by enzyme immunoassay from sera obtained at 18 weeks and 9 months of age. Serotype-specific antibody concentration was compared between groups of children among PCV-11 recipients stratified according to their carriage status at 6 weeks of age. RESULTS: Antibody concentrations to 6B, 19F, and 23F were significantly lower at 18 weeks and 9 months of age among children who were carriers of the specific serotype at 6 weeks of age than among non-carriers of the serotype. The hyporesponsiveness was specific to the carried serotype. The specific antibody concentrations induced by PCV-11 among carriers did not differ significantly from those in placebo recipients, whereas the differences were highly significant among noncarriers. CONCLUSIONS: Pneumococcal carriage, prevalent in Filipino infants, interferes with serotype-specific immune response to primary series of PCV and has potential implications for immunization programs.

Streptococcus pneumoniae capsular serotype 19F is more resistant to C3 deposition and less sensitive to opsonophagocytosis than serotype 6B.

The polysaccharide capsule is a major virulence mechanism of Streptococcus pneumoniae, shielding the bacterium from phagocytes. Capsule types may differ in their abilities to resist immune defense. Antibody-mediated complement activation and opsonophagocytosis are crucial in protection against pneumococcus. Conjugate vaccine trials suggest imperfect protection against 19F. We have previously shown that significantly more anti-19F than anti-6B antibody is needed for killing in the opsonophagocytic assay (OPA). In this study, we explored whether the amount of C3 deposited on serotype 6B and 19F pneumococcal strains reflects their sensitivity to opsonophagocytosis. We compared clinical 6B and 19F nasopharyngeal, middle ear, and blood isolates as well as reference OPA strains (n = 16) for their sensitivity to opsonophagocytosis and C3 deposition. Sixfold anticapsular antibody concentrations were required for 50% opsonophagocytic killing of 19F compared to that of 6B strains. Serotype 19F was more resistant to C3 deposition than 6B. Complement deposition and opsonophagocytosis were dependent on the concentration of anticapsular antibodies. Differences between pneumococcal serotypes in antibody-mediated protection may partly be explained by the abilities of the capsules to resist complement deposition. These findings support previous studies suggesting that higher antibody concentrations to the capsular polysaccharide are needed for protection against disease caused by serotype 19F than that caused by 6B.

Antibody response to the 23-valent pneumococcal polysaccharide vaccine after conjugate vaccine in patients with chronic lymphocytic leukemia.

The 23-valent pneumococcal polysaccharide vaccine (PPV23) given alone is ineffective in patients with chronic lymphocytic leukemia (CLL) and better antibody response is achieved with pneumococcal conjugate vaccines (PCVs). In this study, we determine whether CLL patients would achieve a significant antibody response and broaden their serotype coverage against invasive pneumococcal disease (IPD) with PPV23 given five years after the 7-valent conjugate vaccine (PCV7). A total of 24 patients with CLL and eight controls were vaccinated with PPV23 five years after PCV7. Blood samples for evaluation of antibody response to PCV7 serotypes and PPV23 serotypes 5 and 7 were taken before vaccination and one month after it. Post-vaccination samples were available from 20 patients. IgG antibodies were measured with ELISA. Antibody concentrations after PPV23 were significantly lower in CLL patients for six of the PCV7 serotypes and for both PPV23 serotypes. Only 10% to 15% of CLL patients achieved an antibody response suggested to be protective against IPD. Hence, PCV7 given five years before PPV23 did not improve antibody response in patients with CLL. Based on our results, PPV23 given after a PCV primer is not useful against IPD in CLL patients.

Pneumococcal Haemophilus influenzae protein D conjugate vaccine induces antibodies that inhibit glycerophosphodiester phosphodiesterase activity of protein D.

Haemophilus influenzae outer membrane protein D (PD) is a glycerophosphodiester phosphodiesterase (GlpQ) activity-possessing virulence factor and a promising vaccine antigen, providing 35.3% efficacy against acute otitis media caused by nontypeable H. influenzae (NTHI) when it was used as a carrier protein in a novel pneumococcal PD conjugate (Pnc-PD) vaccine. To study if PD-induced protection against NTHI could be due to antibodies that inhibit or neutralize its enzymatic activity, a GlpQ enzyme inhibition assay was developed, and serum samples collected from Finnish infants before and after Pnc-PD vaccination were analyzed for enzyme inhibition and anti-PD immunoglobulin G (IgG) antibody concentration. Before vaccination at age 2 months, the majority (84%) of infants (n = 69) had no detectable anti-PD IgG antibodies, and all were enzyme inhibition assay negative (inhibition index, <20). At age 13 to 16 months, all infants receiving three or four doses of Pnc-PD had detectable anti-PD IgG antibodies and 36% (8/22 infants) of the infants receiving three doses and 26% (6/23 infants) of the infants receiving four doses of Pnc-PD were inhibition assay positive (inhibition index, >/=20). No significant rise in anti-PD IgG antibodies or enzyme inhibition among control vaccinees (n = 24) receiving three doses of hepatitis B vaccine was detected. A modest correlation (r(s), approximately 0.66) between anti-PD IgG concentration and enzyme inhibition was detected; however, their kinetics were clearly different. These data suggest that measurement of antibody responses that inhibit PD's enzymatic activity could be a useful tool for assessing Pnc-PD vaccine-induced protective immunity against NTHI.

Antibody persistence after pneumococcal conjugate vaccination in patients with chronic lymphocytic leukemia.

Patients with chronic lymphocytic leukemia (CLL) are at a high risk for infections caused by Streptococcus pneumoniae. A pneumococcal conjugate vaccine (PCV) can induce a significant antibody response for some CLL patients. In this study we investigated antibody persistence after PCV7 in patients with CLL. The study material comprised 24 patients with CLL and 8 immunocompetent controls. The median antibody concentrations five years after PCV7 were lower for six pneumococcal serotypes in patients with CLL compared to controls, but the difference was not statistically significant. Depending on the serotype, the percentage of the CLL patients with antibody levels suggested to provide protection against invasive pneumococcal disease (IPD) varied from 29 to 71% five years after vaccination. This data suggests that PCV could result in antibody persistence at least five years in CLL patients.

Antibody responses against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in children with acute respiratory infection with or without nasopharyngeal bacterial carriage.

BACKGROUND: We studied Immunoglobulin G (IgG) antibody responses against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in young children with acute viral type respiratory infection and analyzed the findings in a multivariate model including age, nasopharyngeal carriage of the tested bacteria and pneumococcal vaccination. METHODS: We included 227 children aged 6-23 months with acute respiratory infection. Nasopharyngeal aspirates were tested for bacterial carriage through detection of messenger RNA (mRNA) transcript with nCounter analysis. Acute and convalescent serum samples were tested for IgG antibody response against eight pneumococcal proteins, three proteins from H. influenzae and five proteins from M. catarrhalis in a fluorescent multiplex immunoassay. RESULTS: A two-fold or greater increase in antibodies to S. pneumoniae, H. influenzae and M. catarrhalis was detected in 27.8, 9.7 and 14.1%, respectively. Nasopharyngeal carriage of each of the studied bacteria was not associated with antibody response detection against each respective bacterium. Furthermore, neither age nor pneumococcal vaccination were independently associated to detection of antibody response against the studied bacteria. Children who carried H. influenzae had higher frequency of colonization by M. catarrhalis (175 [80.3%] vs. 2 [22.2%]; p < .001) than those without H. influenzae. Also, children with acute otitis media tended to have higher frequency of antibody response to S. pneumoniae. CONCLUSION: Nasopharyngeal colonization by S. pneumoniae, H. influenzae and M. catarrhalis did not induce significant increases in antibody levels to these bacteria. Carriage of pathogenic bacteria in the nasopharynx is not able to elicit antibody responses to protein antigens similar to those caused by symptomatic infections.

A toddler PCV booster dose following 3 infancy priming doses increases circulating serotype-specific IGG levels but does not increase protection against carriage.

BACKGROUND: We compared PCV7 serological response and protection against carriage in infants receiving 3 doses (2, 4, 6 months; 3+0 schedule) to those receiving a booster (12 months; 3+1). METHODS: A prospective, randomized controlled study, conducted between 2005 and 2008, before PCVs were implemented in Israel. Healthy infants were randomized 1:1:1 to receive 3+1, 3+0 and 0+2 (control group; 12, 18 months doses). Nasopharyngeal/oropharyngeal swabs were obtained at all visits. Serum serotype-specific IgG concentrations and opsonic activities (OPA) were measured at 2, 7, 13 and 19 months. This study was registered with Current Controlled Trials, Ltd. ISRCTN28445844. RESULTS: Overall, 544 infants were enrolled: 3+1 (n = 178), 3+0 (n = 178) and 0+2 (n = 188). Post-priming (7 months), antibody concentrations were similar in both groups, except for serotype 18C (higher in 3+0). Post-booster (13, 19 months), ELISA and OPA levels were significantly higher in 3+1 than in 3+0 group. Nasopharyngeal/oropharyngeal cultures were positive for Streptococcus pneumoniae in 2673 (54.3%) visits. Acquisition rates (vaccine and non-vaccine serotypes) were similar for 3+1 and 3+0 groups at 7-30 months and for 0+2 group at 19-30 months. CONCLUSIONS: PCV7 booster after 3 priming doses increased substantially IgG concentrations but did not further reduced vaccine-serotype nasopharyngeal acquisition, suggesting that protection from pneumococcal carriage does not depend primarily on serum IgG.

Comparison of serological assays using pneumococcal proteins or polysaccharides for detection of Streptococcus pneumoniae infection in children with community-acquired pneumonia.

The aim of this study was to compare the results of serological assays using pneumococcal proteins or polysaccharides for the detection of pneumococcal infection in childhood pneumonia. Serological assays measured IgG against eight pneumococcal proteins (Ply,CbpA,PspA1,PspA2,PcpA,PhtD,StkP-C,PcsB-N), C-polysaccharide [in the whole study population, n = 183], or 19 pneumococcal capsular polysaccharides (1,2,4,5,6B,7F,8,9 V,10A,11A,12F,14,15B,17F,18C,19F,20,23F,33F) [only in a subgroup of patients, n = 53] in paired serum samples of children aged <5 years-old hospitalized with clinical and radiological diagnosis of community-acquired pneumonia. We also performed an inhibition of binding test with the anti-capsular polysaccharide assay in order to confirm the specificity of the antibody responses detected. Invasive pneumococcal pneumonia was investigated by blood culture and PCR (ply-primer). Among 183 children, the anti-protein assay detected antibody response in 77/183(42.1%) patients and the anti-C-polysaccharide assay in 28/183(15.3%) patients. In a subgroup of 53 children, the anti-protein assay detected response in 32/53(60.4%) patients, the anti-C-polysaccharide assay in 11/53(20.8%) patients, and the anti-capsular polysaccharide in 25/53(47.2%) patients. Simultaneous antibody responses against ≥2 different capsular polysaccharides were detected in 11/53(20.8%) patients and this finding could not be explained by cross-reactivity between different serotypes. Among 13 patients with invasive pneumococcal pneumonia, the sensitivity of the anti-protein assay was 92.3%(12/13), of the anti-C-polysaccharide assay 30.8%(4/13), and of the anti-capsular polysaccharide assay 46.2%(6/13). The serological assay using pneumococcal proteins is more sensitive for the detection of pneumococcal infection in children with pneumonia than the assay using pneumococcal polysaccharides. Future studies on childhood pneumonia aetiology should consider applying serological assays using pneumococcal proteins.

Infection by Streptococcus pneumoniae in children with or without radiologically confirmed pneumonia.

OBJECTIVE: Community-acquired pneumonia is an important cause of morbidity in childhood, but the detection of its causative agent remains a diagnostic challenge. The authors aimed to evaluate the role of the chest radiograph to identify cases of community-aquired pneumonia caused by typical bacteria. METHODS: The frequency of infection by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis was compared in non-hospitalized children with clinical diagnosis of community acquired pneumonia aged 2-59 months with or without radiological confirmation (n=249 and 366, respectively). Infection by S. pneumoniae was diagnosed by the detection of a serological response against at least one of eight pneumococcal proteins (defined as an increase ≥2-fold in the IgG levels against Ply, CbpA, PspA1 and PspA2, PhtD, StkP-C, and PcsB-N, or an increase ≥1.5-fold against PcpA). Infection by H. influenzae and M. catarrhalis was defined as an increase ≥2-fold on the levels of microbe-specific IgG. RESULTS: Children with radiologically confirmed pneumonia had higher rates of infection by S. pneumoniae. The presence of pneumococcal infection increased the odds of having radiologically confirmed pneumonia by 2.8 times (95% CI: 1.8-4.3). The negative predictive value of the normal chest radiograph for infection by S. pneumoniae was 86.3% (95% CI: 82.4-89.7%). There was no difference on the rates of infection by H. influenzae and M. catarrhalis between children with community-acquired pneumonia with and without radiological confirmation. CONCLUSIONS: Among children with clinical diagnosis of community-acquired pneumonia submitted to chest radiograph, those with radiologically confirmed pneumonia present a higher rate of infection by S. pneumoniae when compared with those with a normal chest radiograph.

Serum antibodies to the pneumococcal surface proteins PhtB and PhtE in Finnish infants and adults.

We examined naturally acquired antibodies to pneumococcal vaccine candidate proteins PhtB and PhtE in children during their first 2 years of life. Prior culture-confirmed pneumococcal exposure was shown to induce the development of anti-PhtB and -PhtE antibodies. The anti-PhtB or -PhtE antibody concentrations were not significantly associated with a decreased risk of subsequent pneumococcal acute otitis media.

Pneumococcal polysaccharide vaccination administered early after neurotrauma or neurosurgery.

OBJECTIVES: Pneumococcal vaccination is recommended to lower the risk of posttraumatic meningitis, and early vaccination may be of importance. After both trauma and central nervous system injury, immune-suppression may occur, which could affect T-cell function and the response to T-cell dependent vaccines. We therefore aimed to investigate the response to early vaccination with a T-cell independent pneumococcal polysaccharide vaccine (PPSV). METHODS: Thirty-three patients with basilar skull fracture and 23 patients undergoing transsphenoidal pituitary gland surgery were vaccinated with PPSV within 10days after neurotrauma or neurosurgery. Twenty-nine neurosurgical patients vaccinated ⩾3weeks after neurotrauma or neurosurgery served as controls. Serotype-specific anti-polysaccharide binding IgG antibody levels to serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were determined by enzyme immunoassay. RESULTS: The vaccination was safe and a highly significant antibody response was found against all serotypes in all groups (p<0.001 for each of the serotypes). There were no differences between groups or in the group by time interaction in any of the serotypes. After early and late vaccination, protective levels were found in >80% for serotypes 9V, 14, 18C, 19F and 23F and in 70% and 50% for serotypes 6B and 4, respectively. CONCLUSION: Patients vaccinated with PPSV within 10days after neurotrauma or neurosurgery respond similarly to those vaccinated after ⩾3weeks, indicating that PPSV can be administered early after neurotrauma or neurosurgery. CLINICAL TRIALS REGISTRATION: NCT02806284.