Declining mortality from adult pneumococcal infections linked to children's vaccination

Retrospective study on the health and economic burden of hospitalized patients due to pneumonia and invasive pneumococcal infections in Belgium settings

INTRODUCTION

pneumococcal infections are associated with high morbidity, hospitalisation and mortality. The objective of this study was to investigate the health and economic burden of all-cause pneumonia and invasive pneumococcal disease in Belgian hospital settings, by patient's age and risk profile.

METHODS

This descriptive retrospective study was conducted in 17 Belgian hospitals. Univariate and multivariate logistic linear regression models were performed. The Health Insurance and patient's cost perspectives were considered because a few studies report these costs.

RESULTS

The analysis has included 4,712 hospital admissions over the year 2018. Median hospitalization costs were higher for invasive pneumococcal infection diagnosis than for all-cause pneumonia (p < 0,001), respectively 4,051€ and 3,362€. Other factors associated with higher hospitalization cost were patient's high-risk profile, admission to emergency unit, transfer from nursing home, admission to intensive care unit and length of stay.

CONCLUSION

Streptococcus pneumoniae infections remain a public health problem with significant cost for the Health Insurance and poor prognosis. Invasive pneumococcal infections are associated with longer hospital stays and required more intensive care than all other causes of pneumonia, in addition to be more costly, which justifies more attention for vaccination. This study also suggests an increase of economic and health burden with age and presence of underlying conditions.

Mortality of Invasive Pneumococcal Disease following Introduction of the 13-Valent Pneumococcal Conjugate Vaccine in Greenland

Before the incorporation of the 13-valent pneumococcal conjugate vaccine (PCV13) into the childhood vaccination regimen in Greenland in 2010, Inuit populations experienced a substantial prevalence of invasive pneumococcal disease (IPD). The PCV13 introduction has been shown to markedly reduce the incidence of IPD. This current study estimated the impact of PCV13 introduction on IPD mortality in Greenland. This was a nationwide register-based study using all available data on IPD cases 1995-2020 in Greenland. Thirty-one-day IPD case fatality rates (CFR), and all-cause and mortality rates associated with IPD during the period before the introduction of PCV13 (January 1995 to September 2010) were compared with those observed in the post-PCV13 era (September 2010 to October 2020). Standardized mortality ratios (SMRs) expressed differences in mortality by sex, age, region, ethnicity, comorbidity, and serotype. IPD CFR decreased with 24.5% from the pre- to the post-PCV13 period. SMR in IPD patients decreased by 57% (95% CI, 36-75%), and a reduction occurred in all age groups. While SMR in IPD persons ≥60 years remained virtually unchanged, there were no IPD-related deaths in persons ≤39 years in the post-PCV13 period. In conclusion, IPD-related mortality has decreased in Greenland following PCV13 introduction in 2010 in the country.

Pneumolysin as a target for new therapies against pneumococcal infections: A systematic review

BACKGROUND

This systematic review evaluates pneumolysin (PLY) as a target for new treatments against pneumococcal infections. Pneumolysin is one of the main virulence factors produced by all types of pneumococci. This toxin (53 kDa) is a highly conserved protein that binds to cholesterol in eukaryotic cells, forming pores that lead to cell destruction.

METHODS

The databases consulted were MEDLINE, Web of Science, and Scopus. Articles were independently screened by title, abstract, and full text by two researchers, and using consensus to resolve any disagreements that occurred. Articles in other languages different from English, patents, cases report, notes, chapter books and reviews were excluded. Searches were restricted to the years 2000 to 2021. Methodological quality was evaluated using OHAT framework.

RESULTS

Forty-one articles describing the effects of different molecules that inhibit PLY were reviewed. Briefly, the inhibitory molecules found were classified into three main groups: those exerting a direct effect by binding and/or blocking PLY, those acting indirectly by preventing its effects on host cells, and those whose mechanisms are unknown. Although many molecules are proposed as toxin blockers, only some of them, such as antibiotics, peptides, sterols, and statins, have the probability of being implemented as clinical treatment. In contrast, for other molecules, there are limited studies that demonstrate efficacy in animal models with sufficient reliability.

DISCUSSION

Most of the studies reviewed has a good level of confidence. However, one of the limitations of this systematic review is the lack of homogeneity of the studies, what prevented to carry out a statistical comparison of the results or meta-analysis.

CONCLUSION

A panel of molecules blocking PLY activity are associated with the improvement of the inflammatory process triggered by the pneumococcal infection. Some molecules have already been used in humans for other purposes, so they could be safe for use in patients with pneumococcal infections. These patients might benefit from a second line treatment during the initial stages of the infection preventing acute respiratory distress syndrome and invasive pneumococcal diseases. Additional research using the presented set of compounds might further improve the clinical management of these patients.

Evolution, Clinical and Microbiological Characteristics of Invasive Pneumococcal Disease since the Introduction of the Pneumococcal Conjugate Vaccine 13-Valent in Adults over 18 Years Old

Invasive pneumococcal disease (IPD) presents high mortality in the population at risk. The aim of this work is to know the evolution, clinical and microbiological characteristics of IPD in the adult population of Majorca, since the introduction of a public funded program for pneumococcal conjugate vaccine (PCV-13) in the pediatric population in the Balearic Islands in 2016. For this purpose, a retrospective multicenter study was carried out in which all episodes of IPD in adult patients from the four hospitals of the public health system of Majorca were included, comparing the periods between 2012 and 2015 and between 2016 and 2019. Clinical variables, serotypes and antibiotic sensitivity were collected. There were 498 cases of IPD; 56.8% were male with a mean age of 67 (standard deviation: 16). Most infections were bacterial pneumonias (73.7%). Of the total cases, 264 (53%) presented complications. Of the 498 cases, 351 strains were obtained, of which 145 (41.3%) belong to vaccinal serotypes (included in the PCV-13 vaccine) and 206 (58.7%) to non-vaccinal serotypes (not included in the PCV-13 vaccine). The percentage of IPD caused by vaccinal serotypes was lower in the second period (47.8% vs. 34.5%; p = 0.012).

Two multi-fragment recombination events resulted in the β-lactam-resistant serotype 11A-ST6521 related to Spain9V-ST156 pneumococcal clone spreading in south-western Europe, 2008 to 2016

BackgroundThe successful pneumococcal clone Spain9V-ST156 (PMEN3) is usually associated with vaccine serotypes 9V and 14.AimOur objective was to analyse the increase of a serotype 11A variant of PMEN3 as cause of invasive pneumococcal disease (IPD) in Spain and its spread in south-western Europe.MethodsWe conducted a prospective multicentre study of adult IPD in Spain (2008-16). Furthermore, a subset of 61 penicillin-resistant serotype 11A isolates from France, Italy, Portugal and Spain were subjected to whole genome sequencing (WGS) and compared with 238 genomes from the European Nucleotide Archive (ENA).ResultsAlthough the incidence of serotype 11A in IPD was stable, a clonal shift was detected from CC62 (penicillin-susceptible) to CC156 (penicillin-resistant). By WGS, three major 11A-CC156 lineages were identified, linked to ST156 (n = 5 isolates; France, Italy and Portugal), ST166 (n = 4 isolates; France and Portugal) and ST838/6521 (n = 52 isolates; France, Portugal and Spain). Acquisition of the 11A capsule allowed to escape vaccine effect. AP200 (11A-ST62) was the donor for ST156 and ST838/6521 but not for ST166. In-depth analysis of ST838/6521 lineage showed two multi-fragment recombination events including four and seven fragments from an 11A-ST62 and an NT-ST344 representative, respectively.ConclusionThe increase in penicillin-resistant serotype 11A IPD in Spain was linked to the spread of a vaccine escape PMEN3 recombinant clone. Several recombination events were observed in PMEN3 acquiring an 11A capsule. The most successful 11A-PMEN3 lineage spreading in south-western Europe appeared after two multi-fragment recombination events with representatives of two major pneumococcal clones (11A-ST62 and NT-ST344).

Incidence of invasive pneumococcal disease after introduction of the 13-valent conjugate pneumococcal vaccine in British Columbia: A retrospective cohort study

BACKGROUND

A significant reduction in invasive pneumococcal disease (IPD) has been reported, across all ages, following the implementation of 7-valent conjugate pneumococcal vaccine (PCV7) globally, as part of infant immunization programs. We explored the additional impact of PCV13 on IPD over a 14-year period.

METHODS

Using provincial laboratory surveillance and hospitalization data (N = 5791), we calculated the annual incidence of IPD following the implementation of PCV13 vaccine. Poisson regression was used to evaluate changes in the overall incidence of IPD, and serotype-specific IPD between PCV7 (2004-10) and PCV13 (2011-2015) eras.

RESULTS

Overall, IPD rates have seen a modest decline in the PCV13 compared to the PCV7 era (IRR 0.84; 95% CI: 0.79-0.89); this was seen in children ≤2 years of age, and the majority of the adult cohort. Rates of vaccine-type IPD (PCV7 and PCV13) also decreased in the PCV13 era. In contrast, IPD incidence related to non-PCV13 (IRR: 1.56; 95%CI:1.43-1.72) and non-vaccine serotypes (IRR: 2.12; 95%CI:1.84-2.45) increased in the PCV13 era compared to the PCV7 era.

CONCLUSIONS

A modest reduction in IPD from the PCV13 vaccine was observed, with gains limited to the immunized cohort and adults. However, a significant increase in non-vaccine serotypes emphasizes the need for continued surveillance.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine Among Adults: A Systematic Review and Meta-analysis

BACKGROUND

A notable reduction of the pneumococcal disease burden among adults was observed after the introduction of a 7-valent pneumococcal conjugate vaccine (PCV7) in childhood immunization programs. In 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 in many jurisdictions; a comparative assessment of PCV13's impact was missing. Our objective was to summarize the available data and assess the change in the incidence of invasive pneumococcal disease (IPD) in adults after the introduction of PCV13 in childhood immunization programs.

METHODS

We conducted a systematic literature search from January 1946 to May 2017 of randomized, controlled trials and observational studies OBS reporting the incidence of IPD, non-invasive pneumococcal disease, hospitalizations, and mortality in adults for the periods before and after the introduction of PCV13. Incidence rate ratios (IRRs) were pooled across studies using restricted, maximum-likelihood, random-effects models.

RESULTS

From 3306 records,we included 29 OBS studies and 2033961 cases. Significantly lower IPD rates were seen after PCV13 introduction in adults aged <65 years (IRR 0.78, 95% confidence interval [CI] 0.72-0.85) and those aged ≥65 years (IRR 0.86, 95% CI 0.81-0.91). Lower rates of IPD were seen with PCV7 (IRR 0.45, 95% CI 0.38-0.54) and PCV13 serotypes (IRR 0.60, 95% CI 0.54-0.68). A significantly higher IRR of 1.10 (95% CI 1.04-1.17) for non-vaccine serotypes was observed, especially among those aged 65 years and older (IRR 1.20, 95% CI 1.11-1.29).

CONCLUSIONS

PCV13 use in children had a moderate impact on reducing the overall and vaccine-type IPDs, but there was a significant increase in non-vaccine type IPDs among adults, especially in those over 65 years.

Epidemiology of pneumococcal diseases in Spain after the introduction of pneumococcal conjugate vaccines

In Spain, the use of pneumococcal conjugate vaccines (PCVs) has led to a decrease in the incidence of vaccine serotypes causing invasive and non-invasive disease in vaccinated and unvaccinated children and adults. Further, the coverage of most of the resistant serotypes by vaccines resulted in an overall decline in antibiotic resistance. As an undesirable effect, there was an increase in the non-vaccine serotypes causing infection, especially serotypes 1, 7F and 19A after PCV7 and serotype 8 after PCV13 approval, this making the beneficial effect of vaccination less apparent. The inclusion of PCVs in childhood vaccination schedules, its approval for use in healthy adults and the increasing number of serotypes covered by the vaccines in development are strong strategies in the fight against pneumococcal disease. Nonetheless, the epidemiology of Streptococcus pneumoniae infections must be still under surveillance to detect new changes, given the high capacity for recombination and adaptability of this always-surprising microorganism.

Decreasing case fatality rate following invasive pneumococcal disease, North East England, 2006-2016

Declining mortality following invasive pneumococcal disease (IPD) has been observed concurrent with a reduced incidence due to effective pneumococcal conjugate vaccines. However, with IPD now increasing due to serotype replacement, we undertook a statistical analysis to estimate the trend in all-cause 30-day case fatality rate (CFR) in the North East of England (NEE) following IPD. Clinical, microbiological and demographic data were obtained for all laboratory-confirmed IPD cases (April 2006–March 2016) and the adjusted association between CFR and epidemiological year estimated using logistic regression. Of the 2510 episodes of IPD included in the analysis, 486 died within 30 days of IPD (CFR 19%). Increasing age, male sex, a diagnosis of septicaemia, being in ⩾1 clinical risk groups, alcohol abuse and individual serotypes were independently associated with increased CFR. A significant decline in CFR over time was observed following adjustment for these significant predictors (adjusted odds ratio 0.93, 95% confidence interval 0.89–0.98; P = 0.003). A small but significant decline in 30-day all-cause CFR following IPD has been observed in the NEE. Nonetheless, certain population groups remain at increased risk of dying following IPD. Despite the introduction of effective vaccines, further strategies to reduce the ongoing burden of mortality from IPD are needed.

Missed vaccinations and critical care admission: all you may wish to know or rediscover-a narrative review

Most vaccines are so effective that they could lead to the control/elimination of the diseases they target and directly impact on intensive care admissions or complications. This is best illustrated by the use of vaccines against Haemophilus influenzae type b, Streptococcus pneumoniae, zoster, yellow fever, Ebola virus, influenza or measles-but also by third party strategies such as maternal, toddler and care-giver immunization. However, each of these vaccine-induced protection is threatened by insufficient vaccine uptake. Here, we briefly discuss how vaccine hesitancy has led to the resurgence of diseases that were considered as controlled and explore the effect of vaccine-hesitant healthcare workers on nosocomial infections. As intensive care physicians are in charge of polymorbid patients, we briefly summarize the current recommendations for vaccinations in high-risk patients. We finally give some perspective on ongoing research, and discuss how institutional policies and intensive care physicians could play a role in increasing the impact of vaccination, overall and in intensive care units.

Evolution of the β-lactam-resistant Streptococcus pneumoniae PMEN3 clone over a 30 year period in Barcelona, Spain

Objectives

To analyse the epidemiology and genetic evolution of PMEN3 (Spain9V-156), a penicillin-non-susceptible clone of Streptococcus pneumoniae, causing invasive pneumococcal disease (IPD) in Barcelona during 1987-2016.

Methods

WGS was performed on 46 representative isolates and the data were used to design additional molecular typing methods including partial MLST, PCR-RFLP and detection of surface-exposed proteins and prophages, to assign the remaining isolates to lineages. The isolates were also subjected to antimicrobial susceptibility testing.

Results

Two hundred and twenty-seven adult cases of IPD caused by PMEN3 were identified. PMEN3 caused mainly pneumonia (84%) and the 30 day mortality rate was 23.1%. Evidence of recombination events was found, mostly in three regions, namely the capsular operon (associated with capsular switching) and adjacent regions containing pbp2x and pbp1a, the murM gene and the pbp2b-ddl region. Some of these genetic changes generated successful new variant serotype lineages, including one of serotype 11A that is not included in the current PCV13 vaccine. Other genetic changes led to increased MICs of β-lactams. Notably, most isolates also harboured prophages coding for PblB-like proteins. Despite these adaptations, the ability of this clone to cause IPD remained unchanged over time, highlighting the importance of its core genetic background.

Conclusions

Our study demonstrated successful adaptation of PMEN3 to persist over time despite the introduction of broader antibiotics and conjugate vaccines. In addition to enhancing understanding of the molecular evolution of PMEN3, these findings highlight the need for the development of non-serotype-based vaccines to fight pneumococcal infection.

Persistence of pneumococcal antibodies after primary immunisation with a polysaccharide-protein conjugate vaccine

INTRODUCTION

Despite immunisation, antibiotics and intensive care management, infection with Streptococcus pneumoniae remains a major cause of morbidity and mortality in children. The WHO currently recommends vaccinating infants with either a 3+0 schedule (6 weeks, 3-4 and 4-6 months of age) or 2+1 schedule (2 doses before 6 months of age, plus a booster dose at 9-15 months of age). This study investigated pneumococcal antibody responses, including persistence of antibodies, after immunisation of healthy infants with a 3+0 schedule.

METHODS

We measured pneumococcal antibody concentrations to all 13 antigens included in the 13-valent pneumococcal conjugate vaccine (PCV13) after immunisation with a 3+0 schedule in 91 infants at 7 months and in 311 infants at 13 months of age. The geometric mean concentrations (GMCs) and the proportion of infants with an antibody concentration above the standard threshold correlate of protection (seroprotection rate) were calculated at both time points.

RESULTS

At 7 months of age, GMCs varied between 0.52 µg/mLand 11.52 µg/mL, and seroprotection rates varied between 69% and 100%. At 13 months of age, GMCs had decreased to between 0.22 µg/mLand 3.09 µg/mL, with the lowest responses against serotype 4, followed by 19A, 3, 6B and 23F. Seroprotection rates at 13 months of age were below 90% for most serotypes, with the lowest rates for serotype 4 (23%) followed by 19A (50%), 23F (61%) and 6B (64%).

CONCLUSION

Our study shows that at 13 months of age, many infants vaccinated with a 3+0 schedule have pneumococcal antibody concentrations below the standard threshold correlate of protection. To optimise protection against pneumococcal disease through early childhood and to improve antibody persistence and indirect protective effects, immunisation schedules with booster doses might be necessary.

High Immunogenicity of the Pneumococcal Conjugated Vaccine in Immunocompromised Adults With Inflammatory Bowel Disease

INTRODUCTION

Patients with inflammatory bowel disease (IBD) are predisposed to pneumococcal infections due to their underlying disease and iatrogenic immunosuppression. Vaccination with the 13-valent pneumococcal conjugated vaccine (PCV13) is recommended, but with poor take-up and few data available. We performed an open-label, phase IV, multicenter study to evaluate the safety and immunogenicity of PCV13 in adults with IBD and to analyze the influence of immunomodulating treatments on anti-pneumococcal seroresponses.

METHODS

We enrolled 306 patients with IBD from March 2014 through February 2016, with the following exclusion criteria: current IBD flare, pregnancy, pneumococcal immunization in the previous 5 years, and influenza immunization in the previous 4 weeks. PCV13 was administered intramuscularly. Serotype-specific vaccine responses were evaluated using an opsonophagocytic assay. Adverse events were monitored by diary cards and standardized phone interviews.

RESULTS

The median seroprotection rate increased significantly from 43.9% (95% confidence interval [CI], 42.3-45.5) at inclusion to 90.4% (95% CI, 89.5-91.3%; P < 0.001) after vaccination. Patients receiving anti-tumor necrosis factor agents achieved a slightly lower seroprotection rate (from 44.5% [95% CI, 42.3%-46.8%] to 86.6% [95% CI, 84.9%-88.1%]) than patients treated with other types of immunosuppressive regimens (thiopurine, methotrexate, oral corticosteroids; from 44.7% [95% CI, 41.7%-47.7%] to 93.8% [95% CI, 92.1%-95.2%]) or nonimmunosuppressive treatment (5-aminosalicylate, topical corticosteroids, vedolizumab; from 41.3% [95% CI, 37.9%-44.8%] to 95.2% [95% CI, 93.4%-96.6%]). There were no safety issues.

DISCUSSION

Overall, the administration of PCV13 was highly immunogenic and well tolerated, irrespective of the baseline treatment, and should be encouraged in all adults with IBD.

Vaccination of Icelandic Children with the 10-Valent Pneumococcal Vaccine Leads to a Significant Herd Effect among Adults in Iceland

The introduction of pneumococcal conjugate vaccines (PCVs) into childhood vaccination programs has reduced carriage of vaccine serotypes and pneumococcal disease. The 10-valent PCV was introduced in Iceland in 2011. The aim of this study was to determine PCV impact on the prevalence of serotypes, genetic lineages, and antimicrobial-resistant pneumococci isolated from the lower respiratory tract (LRT) of adults. Pneumococci isolated between 2009 and 2017 at the Landspitali University Hospital were included (n = 797). The hospital serves almost three-quarters of the Icelandic population. Isolates were serotyped and tested for antimicrobial susceptibility, and the genome of every other isolate collected between 2009 and 2014 was sequenced (n = 275). Serotypes and multilocus sequence types (STs) were extracted from the genome data. Three study periods were defined, 2009 to 2011 (PreVac), 2012 to 2014 (PostVac-I), and 2015 to 2017 (PostVac-II). The total number of isolates and vaccine-type (VT) pneumococci decreased from PreVac to PostVac-II (n = 314 versus n = 230 [p = 0.002] and n = 170 versus n = 33 [p < 0.001], respectively), but non-vaccine-type (NVT) pneumococci increased among adults 18 to 64 years old (n = 56 versus n = 114 [p = 0.008]). Serotype 19F decreased in the PostVac-II period; these isolates were all multidrug resistant (MDR) and were members of the Taiwan^19F-14 PMEN lineage. Serotype 6A decreased among adults ≥65 years old in the PostVac-II period (p = 0.037), while serotype 6C increased (p = 0.021) and most serotype 6C isolates were MDR. Nonencapsulated Streptococcus pneumoniae (NESp) isolates increased among adults 18 to 64 years old in the PostVac-II period, and the majority were MDR (p = 0.028). An overall reduction in the number of LRT samples and pneumococcus-positive cultures and significant changes in the serotype distribution became evident within 4 years, thereby demonstrating a significant herd effect.

Host-pathogen interactions and prognosis of critically ill immunocompetent patients with pneumococcal pneumonia: the nationwide prospective observational STREPTOGENE study

PURPOSE

To assess the relative importance of host and bacterial factors associated with hospital mortality in patients admitted to the intensive care unit (ICU) for pneumococcal community-acquired pneumonia (PCAP).

METHODS

Immunocompetent Caucasian ICU patients with PCAP documented by cultures and/or pneumococcal urinary antigen (UAg Sp) test were included in this multicenter prospective study between 2008 and 2012. All pneumococcal strains were serotyped. Logistic regression analyses were performed to identify risk factors for hospital mortality.

RESULTS

Of the 614 patients, 278 (45%) had septic shock, 270 (44%) had bacteremia, 307 (50%) required mechanical ventilation at admission, and 161 (26%) had a diagnosis based only on the UAg Sp test. No strains were penicillin-resistant, but 23% had decreased susceptibility. Of the 36 serotypes identified, 7 accounted for 72% of the isolates, with different distributions according to age. Although antibiotics were consistently appropriate and were started within 6 h after admission in 454 (74%) patients, 116 (18.9%) patients died. Independent predictors of hospital mortality in the adjusted analysis were platelets ≤ 100 × 10⁹/L (OR, 7.7; 95% CI, 2.8-21.1), McCabe score ≥ 2 (4.58; 1.61-13), age > 65 years (2.92; 1.49-5.74), lactates > 4 mmol/L (2.41; 1.27-4.56), male gender and septic shock (2.23; 1.30-3.83 for each), invasive mechanical ventilation (1.78; 1-3.19), and bilateral pneumonia (1.59; 1.02-2.47). Women with platelets ≤ 100 × 10⁹/L had the highest mortality risk (adjusted OR, 7.7; 2.8-21).

CONCLUSIONS

In critically ill patients with PCAP, age, gender, and organ failures at ICU admission were more strongly associated with hospital mortality than were comorbidities. Neither pneumococcal serotype nor antibiotic regimen was associated with hospital mortality.

Serotypes and genotypes of S. pneumoniae isolates from adult invasive disease in Spain: A 5-year prospective surveillance after pediatric PCV13 licensure. The ODIN study

Serotypes/genotypes causing invasive pneumococcal disease (IPD) in adults are determined by vaccination strategies. The aim of this study was to assess the epidemiology of IPD in adults (≥18 years) after PCV13 introduction for children: serotypes, clonal complexes, antibiotic non-susceptibility and clinical presentations. We performed a prospective, clinical surveillance of hospitalized culture-confirmed IPDs in adults in nine Spanish hospitals (August 2010-June 2015). A total of 1087 culture-confirmed IPD episodes were included, of which 772 (71.0%) had bacteremic pneumonia (401 complicated/371 uncomplicated pneumonia), 122 (11.2%) meningitis, 102 (9.4%) non-focal bacteremia, 34 (3.1%) peritonitis and 57 (5.3%) others. The most common serotypes were: 3 (12.7%), 19A (8.5%), 8 (7.7%), 7F (6.3%), 1 (4.2%), 6C (4.2%), 11A (4.2%), 22F (4.2%) and 14 (4.0%). Vaccine types (PCV13 + 6C) caused 49.8% of IPD episodes, with a significant decrease over the 5-year period, and significant decreases in serotypes 6C and 7F. The most common genotypes were: CC180 (8.4%), CC191 (6.0%), and CC53 (5.0%). Vaccine types caused 53.9% (414/768) pneumonia episodes and 58.9% (235/399) complicated pneumonia, 53.4% IPD in adults <50 years (143/268), and 54.7% IPD in immunocompetent patients (337/616). Overall non-susceptibility was 25.9% to penicillin (1.1% for parenteral criteria), 24.9% to erythromycin and 2.7% to levofloxacin. CONCLUSIONS: Although the percentage of vaccine-types causing IPDs in adults significantly decreased, it remained high. Associations of vaccine types with pneumonia (with complicated pneumonia for specific serotypes), and immunocompetent patients point to the burden of IPD caused by PCV13 serotypes.

Decreased relative risk of pneumococcal pneumonia during the last decade, a nested case-control study

Background

Streptococcus pneumoniae (SP) is one of the most common pathogens of Community-Acquired Pneumonia (CAP), but recent reports suggest that its incidence may be declining in relation to the use of the conjugate 13-valent pneumococcal vaccine in children. We compared the result of the immunochromatographic SP urinary antigen test (SPUAT) and clinical outcomes in patients with CAP admitted in two periods of time: 2001–2002(CAP1) and 2015–2016(CAP2).

Methods

This was a matched nested case-control study of two prospectively recorded cohorts of patients admitted with CAP, with SPUAT and blood culture performed in all patients. CAP2 cases and CAP1 controls were matched for age ± 4 years, sex, and Pneumonia Severity Index (PSI) score ± 10 points. Odds ratios (OR) for having SPUAT positive was estimated by conditional logistic regression. A multivariate model assessed the contribution of individual variables.

Results

Four hundred ninety-eight patients were recruited; 307 during the CAP1 and 191 during the CAP2 periods. Comparing both periods we observed differences, in age, PSI score, and the percentage of smokers, outpatients, previously immunized with pneumococcal vaccine, and positive SPUAT. On the other hand, mortality, admission from nursing homes, pneumococcal bacteremia and hospital admission were not different. After matching, pneumonia due to SP per the SPUAT was observed in 34(23.4%) of CAP1 and in 12(8.3%) of CAP2 patients (p < 0.001), and 6/145 CAP1 vs 33/145 CAP2 patients had received pneumococcal immunization before their admission (p < 0.001). A multivariate analysis confirmed that, independent of falling into PSI class 5, having not received the pneumococcal vaccine and having not survived the episode of pneumonia, there were two factors that increased the probability of having SPUAT positive: developing pneumonia during the CAP1 period (OR = 1.23) and having pneumococcal bacteremia (OR = 2.66).

Conclusion

We observed a reduction of the role of SP as pathogen, along with an increase in the number of patients who received pneumococcal immunization before admission, in 2015-2016 compared to 2001-2002. In addition, the use of conjugate 13-valent vaccine, starting in 2012 for childhood immunization, could be an additional factor contributing to these changes, as a result of early herd immunity in adults pneumonia.

Serotype distribution of invasive Streptococcus pneumoniae in adults 65 years of age and over after the introduction of childhood 13-valent pneumococcal conjugate vaccination programs in Canada, 2010-2016

The 13-valent conjugate vaccine (PCV13) was recommended for childhood immunization programs in 2010 in Canada and has decreased the incidence of invasive pneumococcal disease (IPD) in children and changed the epidemiology of IPD in adults. This study investigated the epidemiology of IPD in adults 65 years of age and older in Canada. A total of 7282 invasive S. pneumoniae isolated from adults ≥65 years old were serotyped from 2010 to 2016 and antimicrobial susceptibility was performed on 2527 isolates. Serotyping was performed by Quellung reaction using commercial antisera and antimicrobial susceptibilities were determined by broth microdilution. PCV7 serotypes decreased non-significantly from 2010 to 2016 from 9.1% (n = 96) to 6.7% (n = 72) while the additional six PCV13 serotypes declined significantly from 39.5% (n = 418) to 18.6% (n = 201) (p < 0.05). The 23-valent pneumococcal polysaccharide vaccine (PPV23) and non-vaccine (NVT) serotypes increased from 26.3% (n = 278) to 36.2% (n = 393) (p < 0.05), and from 25.1% (n = 266) to 38.4% (n = 416) (p < 0.05), respectively. There were no significant changes in antimicrobial resistance rates from 2011 to 2016: 24.1% of the IPD from adults ≥65 years were resistant to clarithromycin (n = 609), 10.0% to doxycycline (n = 254), 11.8% to penicillin (n = 299), 5.2% to cefuroxime (n = 131), 6.6% to clindamycin (n = 168), 6.0% to trimethoprim-sulfamethoxazole (n = 152), and 0.5% (n = 12) to ceftriaxone. Although overall incidence of IPD in adults ≥65 years has remained relatively constant from 2010 to 2016, childhood PCV13 vaccination programs have been successful in indirectly reducing IPD caused by PCV13 serotypes in adults through herd immunity effects.

Childhood Deaths Attributable to Invasive Pneumococcal Disease in England and Wales, 2006-2014

Background

Pneumococcal conjugate vaccines (PCVs) are highly effective in preventing invasive pneumococcal disease (IPD), but deaths due to IPD still occur. We aimed to describe children who died of IPD since PCV introduction in England and Wales.

Methods

Public Health England conducts enhanced IPD surveillance in England and Wales. IPD cases in PCV-eligible children aged <5 years (born since 4 September 2004 and diagnosed between 4 September 2006 and 3 September 2014) were actively followed up by postal questionnaires and, for fatal cases, detailed information was requested prospectively from multiple sources.

Results

During the 8-year period, there were 3146 IPD cases and 150 IPD-related deaths (case fatality rate, 4.8%). Overall, 132 isolates from fatal cases were serotyped (88%) and 35 distinct serotypes were identified, with no serotype predominance. Most deaths occurred in children aged <1 year (88/150 [59%]) and 1-year-olds (36/150 [24%]). One-third (53/150 [35%]) had a known risk factor for IPD. Clinical presentation varied with age but not by serotypes in the different conjugate vaccines. Meningitis was diagnosed in nearly half the fatal cases (71/150 [47%]). The IPD-related mortality rate declined after 7-valent PCV introduction from 1.25/100000 children in 2006-2007 to 0.60/100000 in 2009-2010, with a further reduction following 13-valent PCV introduction from April 2010 to 0.39/100000 in 2013-2014 (14 deaths; incidence rate ratio, 0.31 [95% confidence interval, .16-.61]; P = .0003), when most deaths were due to nonvaccine serotypes or in neonates.

Conclusions

Most fatal IPD cases are currently not vaccine-preventable. Additional strategies will be required to reduce childhood pneumococcal deaths in countries with established pneumococcal vaccination programs.

Treatment and prevention of invasive pneumococcal disease

Invasive pneumococcal disease is a severe infection that mainly affects patients with associated comorbidity. The paediatric conjugate vaccination has resulted in a change in the adult vaccination strategy. The antibiotic resistance of pneumococcus is not currently a severe problem. Nevertheless, the World Health Organisation has included pneumococcus among the bacteria whose treatment requires the introduction of new drugs, such as ceftaroline and ceftobiprole. Although the scientific evidence is still limited, the combination of beta-lactams and macrolides is recommended as empiric therapy for bacteraemic pneumococcal pneumonia.

Pneumococcal Vaccination Guidance for Post-Acute and Long-Term Care Settings: Recommendations From AMDA's Infection Advisory Committee

Efforts at preventing pneumococcal disease are a national health priority, particularly in older adults and especially in post-acute and long-term care settings The Advisory Committee on Immunization Practices recommends that all adults ≥65 years of age, as well as adults 18-64 years of age with specific risk factors, receive both the recently introduced polysaccharide-protein conjugate vaccine against 13 pneumococcal serotypes as well as the polysaccharide vaccine against 23 pneumococcal serotypes. Nursing facility licensure regulations require facilities to assess the pneumococcal vaccination status of each resident, provide education regarding pneumococcal vaccination, and administer the appropriate pneumococcal vaccine when indicated. Sorting out the indications and timing for 13 pneumococcal serotypes and 23 pneumococcal serotypes administration is complex and presents a significant challenge to healthcare providers. Here, we discuss the importance of pneumococcal vaccination for older adults, detail AMDA-The Society for Post-Acute and Long-Term Care Medicine (The Society)'s recommendations for pneumococcal vaccination practice and procedures, and offer guidance to postacute and long-term care providers supporting the development and effective implementation of pneumococcal vaccine policies.

Indirect (herd) protection, following pneumococcal conjugated vaccines introduction: A systematic review of the literature

BACKGROUND

Pneumococcal diseases are major causes of morbidity among adults, especially those over 50years of age. While pneumococcal conjugated vaccines (PCV's) impact on pneumococcal disease rates among children is well established, the extent of its impact on adult pneumococcal related illness remains unclear. The aim of this systematic literature review was to describe the impact of PCV introduction to childhood national immunization programs worldwide on PCV-naive adult population.

METHODS

A systematic literature search was performed using the PubMed database. The search was limited to articles written in English and published between January 2000 and February 2016. Studies evaluating pneumococcal disease rates in individuals over 5years of age were included. Independent extraction of articles was performed by the two authors. Search terms included: Pneumococcal conjugated vaccine, herd, indirect, adults, and pneumonia.

RESULTS

Forty-nine articles meeting the selection criteria were identified, 39 regarding invasive pneumococcal disease (IPD, one on meningitis only), 8 regarding pneumonia, and 2 on both IPD and pneumonia. The majority of reports were from the US, UK and Canada. Considerable variability in the data sources, quality and completeness was observed. While most studies reported either statistically significant reduction or insignificant changes in IPD and pneumonia disease rates in adults following PCV nationwide implementation, few studies reported statistically significant increase in pneumococcal disease rates, these were mainly from countries with low PCV coverage rates and/or inadequate surveillance.

CONCLUSION

Invasive pneumococcal diseases and pneumonia rates among the adult population decreased in most countries following PCV introduction into the NIP. This indirect effect on older population seems to be dependent on PCV coverage rates and time from PCV nationwide implementation. Adults >65years old seem to benefit the most from PCV introduction.

From Immunologically Archaic to Neoteric Glycovaccines

Polysaccharides (PS) are present in the outermost surface of bacteria and readily come in contact with immune cells. They interact with specific antibodies, which in turn confer protection from infections. Vaccines with PS from pneumococci, meningococci, Haemophilus influenzae type b, and Salmonella typhi may be protective, although with the important constraint of failing to generate permanent immunological memory. This limitation has in part been circumvented by conjugating glycovaccines to proteins that stimulate T helper cells and facilitate the establishment of immunological memory. Currently, protection evoked by conjugated PS vaccines lasts for a few years. The same approach failed with PS from staphylococci, Streptococcus agalactiae, and Klebsiella. All those germs cause severe infections in humans and often develop resistance to antibiotic therapy. Thereby, prevention is of increasing importance to better control outbreaks. As only 23 of more than 90 pneumococcal serotypes and 4 of 13 clinically relevant Neisseria meningitidis serogroups are covered by available vaccines there is still tremendous clinical need for PS vaccines. This review focuses on glycovaccines and the immunological mechanisms for their success or failure. We discuss recent advances that may facilitate generation of high affinity anti-PS antibodies and confer specific immunity and long-lasting protection.

Epidemiology, virulence factors and management of the pneumococcus

Pneumococcal infections continue to cause significant morbidity and mortality in patients throughout the world. This microorganism remains the most common bacterial cause of community-acquired pneumonia and is associated with a considerable burden of disease and health-care costs in both developed and developing countries. Emerging antibiotic resistance has been a concern because of its potential negative impact on the outcome of patients who receive standard antibiotic therapy. However, there have been substantial changes in the epidemiology of this pathogen in recent years, not least of which has been due to the use of pneumococcal conjugate vaccines in children, with subsequent herd protection in unvaccinated adults and children. Furthermore, much recent research has led to a better understanding of the virulence factors of this pathogen and their role in the pathogenesis of severe pneumococcal disease, including the cardiac complications, as well as the potential role of adjunctive therapy in the management of severely ill cases. This review will describe recent advances in our understanding of the epidemiology, virulence factors, and management of pneumococcal community-acquired pneumonia.