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Aerospace Medicine and Human Performance Dec 2022There is debate whether astronauts traveling to space should undergo a prophylactic splenectomy prior to long duration spaceflight. Risks to the spleen during flight...
There is debate whether astronauts traveling to space should undergo a prophylactic splenectomy prior to long duration spaceflight. Risks to the spleen during flight include radiation and trauma. However, splenectomy also carries significant risks. Systematic review of data published over the past 5 decades regarding risks associated with splenectomies and risks associated with irradiation to the spleen from long duration spaceflight were analyzed. A total of 41 articles were reviewed. Acute risks of splenectomy include intraoperative mortality rate (from hemorrhage) of 3-5%, mortality rate from postoperative complications of 6%, thromboembolic event rate of 10%, and portal vein thrombosis rate of 5-37%. Delayed risks of splenectomy include overwhelming postsplenectomy infection (OPSI) at 0.5% at 5 yr post splenectomy, mortality rate as high as 60% for pneumococcal infections, and development of malignancy with relative risk of 1.53. The risk of hematologic malignancy increases significantly when individuals reach 40 Gy of exposure, much higher than the 0.6 Gy of radiation experienced from a 12-mo round trip to Mars. Lower doses of radiation increase the risk of hyposplenism more so than hematologic malignancy.For protection against hematologic malignancy, the benefits of prophylactic splenectomy do not outweigh the risks. However, there is a possible risk of hyposplenism from long duration spaceflight. It would be beneficial to prophylactically provide vaccines against encapsulated organisms for long duration spaceflight to mitigate the risk of hyposplenism.
Topics: Humans; Splenectomy; Spleen; Pneumococcal Infections; Postoperative Complications; Space Flight
PubMed: 36757247
DOI: 10.3357/AMHP.6079.2022 -
Blood Advances Nov 2023Children with sickle cell disease (SCD) are at increased risk of invasive pneumococcal disease (IPD). Over 25 years, the Georgia Emerging Infections Program/Centers for...
Children with sickle cell disease (SCD) are at increased risk of invasive pneumococcal disease (IPD). Over 25 years, the Georgia Emerging Infections Program/Centers for Disease Control and Prevention Active Bacterial Core Surveillance network identified 104 IPD episodes among 3707 children with hemoglobin SS (HbSS) or HbSC aged <10 years, representing 6% of IPD in Black or African American children residing in Metropolitan Atlanta (reference population). Children with IPD and HbSS/SC were older than those with IPD in the reference population (P < .001). From 1994-1999 to 2010-2018, IPD declined by 87% in children with HbSS aged 0 to 4 years, and by 80% in those aged 5 to 9 years. However, IPD incidence rate ratios when comparing children with SCD with the reference population increased from 20.2 to 29.2 over these periods. Among children with HbSS and IPD, death declined from 14% to 3% after 2002, and meningitis declined from 16% to 8%. Penicillin resistance was more prevalent in children with SCD before 7-valent pneumococcal conjugate vaccine (PCV7) licensure. After 2010, all IPD serotypes were not included in the 13-valent PCV (PCV13). Within 3 years of vaccination, the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) against non-PCV13 serotypes included in PPSV23 plus 15A/15C was 92% (95% confidence interval, 40.8- 99.0, P = .014; indirect-cohort effect adjusted for age and hydroxyurea). PPSV23 would cover 62% of non-PCV13 serotype IPD in children with SCD, whereas PCV15, PCV20, and PCV21/V116 (in development) could cover 16%, 51%, and 92%, respectively. Although less frequent, IPD remains a life-threatening risk in children with SCD. Effective vaccines with broader coverage could benefit these children.
Topics: Humans; Child; Heptavalent Pneumococcal Conjugate Vaccine; Vaccines, Conjugate; Pneumococcal Infections; Serogroup; Anemia, Sickle Cell; Hemoglobin, Sickle
PubMed: 37698500
DOI: 10.1182/bloodadvances.2022009643 -
Frontiers in Cellular and Infection... 2022
Topics: Humans; Nasopharynx; Pneumococcal Infections; Streptococcus pneumoniae
PubMed: 36176577
DOI: 10.3389/fcimb.2022.1028047 -
Clinical Microbiology and Infection :... Jan 2020Of over 90 serotypes of Streptococcus pneumoniae, only seven were included in the first pneumococcal conjugate vaccine (PCV). While PCV reduced the disease incidence, in... (Review)
Review
BACKGROUND
Of over 90 serotypes of Streptococcus pneumoniae, only seven were included in the first pneumococcal conjugate vaccine (PCV). While PCV reduced the disease incidence, in part because of a herd immunity effect, a replacement effect was observed whereby disease was increasingly caused by serotypes not included in the vaccine. Dynamic transmission models can account for these effects to describe post-vaccination scenarios, whereas economic evaluations can enable decision-makers to compare vaccines of increasing valency for implementation.
AIM
The aim of this review was to examine epidemiological and economic models and their assumptions for their potential contributions to future research and immunisation policy.
SOURCES
Pubmed, Scopus, Ovid, ISI Web of Knowledge, Centre of Reviews and Dissemination (CRD) databases were searched.
CONTENT
Twenty-three dynamic transmission models and 21 economic models were retrieved and reviewed. Published models employed various templates, revealing several key uncertainties regarding the biology and epidemiology of pneumococcal infection. While models suggested that PCVs will reduce the burden of disease, the extent to which they are predicted to do so depended on various assumptions regarding features of pneumococcal infection and epidemiology that governed PCV cost-effectiveness as well. Such features include the duration of protection and competitive interactions between serotypes, which are unclear at present, but which directly relate to herd immunity and serotype replacement.
IMPLICATIONS
Economic evaluations are not typically based on transmission dynamic models and hence omit indirect herd immunity effects. The two tools could be used in conjunction to inform decision-makers on vaccine implementation, but so far there have been few attempts to build economic evaluations on transmission dynamic models, and none in this field. Future directions for research could include studies to evaluate key parameters for the models involving herd immunity, serotype competition and the natural history of infection.
Topics: Cost-Benefit Analysis; Decision Support Techniques; Humans; Immunity, Herd; Models, Economic; Pneumococcal Infections; Pneumococcal Vaccines; Serogroup; Streptococcus pneumoniae; Vaccination; Vaccines, Conjugate
PubMed: 31055164
DOI: 10.1016/j.cmi.2019.04.026 -
Frontiers in Cellular and Infection... 2021Secondary bacterial infections enhance the disease burden of influenza infections substantially. (the pneumococcus) plays a major role in the synergism between... (Review)
Review
Secondary bacterial infections enhance the disease burden of influenza infections substantially. (the pneumococcus) plays a major role in the synergism between bacterial and viral pathogens, which is based on complex interactions between the pathogen and the host immune response. Here, we discuss mechanisms that drive the pathogenesis of a secondary pneumococcal infection after an influenza infection with a focus on how pneumococci senses and adapts to the influenza-modified environment. We briefly summarize what is known regarding secondary bacterial infection in relation to COVID-19 and highlight the need to improve our current strategies to prevent and treat viral bacterial coinfections.
Topics: COVID-19; Coinfection; Host-Pathogen Interactions; Humans; Influenza, Human; Pneumococcal Infections; Respiratory System; Respiratory Tract Infections; Streptococcus pneumoniae
PubMed: 33828999
DOI: 10.3389/fcimb.2021.643326 -
Cellular and Molecular Biology... Jan 2022Streptococcus pneumoniae is the bacterium that causes pneumococcal disease which often results in pneumonia, meningitis, otitis media, septicemia and sinusitis.... (Review)
Review
Streptococcus pneumoniae is the bacterium that causes pneumococcal disease which often results in pneumonia, meningitis, otitis media, septicemia and sinusitis. Pneumonia, particularly, is a significant cause of worldwide morbidity and a global health burden as well. Treatment often relies on antimicrobials, to which the pathogen is frequently mutating and rendering infective. Consequently, vaccination is the most effective approach in dealing with pneumococcal antimicrobial resistance (AMR). Unfortunately, the current pneumococcal polysaccharide and conjugate vaccines have a narrow serotype coverage. Therefore, the current need for vaccines with a broader serotype coverage cannot be overstated. Pneumococcal Surface Protein A and C are potential vaccine candidate antigens present in over 90% of the strains from clinical isolates as well as laboratory non-encapsulated strains. Pneumococcal Surface Protein A is an active virulent factor that pneumococci use to evade complement-mediated host immune responses and has been shown to elicit immune responses against pneumococcal infections. This review explores the potential utilization of Pneumococcal Surface Protein A to immunize against S. pneumoniae.
Topics: Bacterial Proteins; Humans; Pneumococcal Infections; Pneumococcal Vaccines; Streptococcus pneumoniae
PubMed: 35809277
DOI: 10.14715/cmb/2021.67.4.32 -
Revue Medicale de Liege Nov 2022Streptococcus pneumoniae infections cause bacteremic and non-bacteremic community-acquired pneumonia and invasive pneumococcal diseases (IPD) such as bacteremia, sepsis...
Streptococcus pneumoniae infections cause bacteremic and non-bacteremic community-acquired pneumonia and invasive pneumococcal diseases (IPD) such as bacteremia, sepsis and acute meningitis. They are potentially lethal. Although polysaccharide vaccines (PPV23, Pneumovax 23®) have already provided protection in at-risk individuals, they have been imperfect, mainly because the development of anti-polysaccharide antibodies occurs without the help of T cells. The introduction of immunogenic protein conjugate vaccines (ICVs) has overcome this problem and provided better and longer lasting protection. The first available vaccine of this type for adults was Prevenar 13®, targeting 13 polysaccharides of S. pneumoniae (PCV13). A new vaccine, Apexxnar®, targeting 20 polysaccharides (PCV20), the 13 of Prevenar 13®, to which 7 other serotypes considered to be equally responsible for invasive infections have been added, has recently been launched. Clinical studies have demonstrated a good immunogenic response against all 20 serotypes in adult patients who are either vaccine-naive or previously vaccinated with PPV23 and/or PCV13. Furthermore, the tolerance of the PCV20 vaccine was found to be comparable to that of Prevenar 13®. Vaccination with PCV20 involves a single injection. The Belgian Superior Health Council has recently reiterated the importance of vaccinating at-risk individuals against S. pneumoniae (a vaccination that is still under-performed). It now recommends vaccination with PCV20 (Apexxnar®) as the preferred primary vaccination regimen in high-risk adults with co-morbidities or in good health aged between 65 and 85 years.
Topics: Adult; Humans; Aged; Aged, 80 and over; Vaccines, Conjugate; Pneumonia, Pneumococcal; Pneumococcal Vaccines; Streptococcus pneumoniae; Pneumococcal Infections; Vaccination
PubMed: 36354231
DOI: No ID Found -
Expert Review of Vaccines 2023Pneumococcal disease (PD) significantly contributes to morbidity and mortality, carrying substantial economic and public health burden. This article is a targeted review... (Review)
Review
A review of evidence for pneumococcal vaccination in adults at increased risk of pneumococcal disease: risk group definitions and optimization of vaccination coverage in the United Kingdom.
INTRODUCTION
Pneumococcal disease (PD) significantly contributes to morbidity and mortality, carrying substantial economic and public health burden. This article is a targeted review of evidence for pneumococcal vaccination in the UK, the definitions of groups at particular risk of PD and vaccine effectiveness.
AREAS COVERED
Relevant evidence focusing on UK data from surveillance systems, randomized controlled trials, observational studies and publicly available government documents is collated and reviewed. Selected global data are included where appropriate.
EXPERT OPINION
National vaccination programs have reduced the incidence of vaccine-type PD, despite the rising prominence of non-vaccine serotypes in the UK. The introduction of higher-valency conjugate vaccines provides an opportunity to improve protection against PD for adults in risk groups. Several incentives are in place to encourage general practitioners to vaccinate risk groups, but uptake is low-suboptimal particularly among at-risk individuals. Wider awareness and understanding among the public and healthcare professionals may increase vaccination uptake and coverage. National strategies targeting organizational factors are urgently needed to achieve optimal access to vaccines. Finally, identifying new risk factors and approaches to risk assessment for PD are crucial to ensure those at risk of PD can benefit from pneumococcal vaccination.
Topics: Adult; Humans; Vaccination Coverage; Pneumococcal Vaccines; Pneumococcal Infections; Vaccination; United Kingdom; Vaccines, Conjugate; Risk Factors
PubMed: 37694398
DOI: 10.1080/14760584.2023.2256394 -
Microbiology Spectrum Jun 2022The nasopharyngeal commensal Streptococcus pneumoniae can become invasive and cause metastatic infection. This requires the pneumococcus to have the ability to adapt,...
The nasopharyngeal commensal Streptococcus pneumoniae can become invasive and cause metastatic infection. This requires the pneumococcus to have the ability to adapt, grow, and reside in diverse host environments. Therefore, we studied whether the likelihood of severe disease manifestations was related to pneumococcal growth kinetics. For 383 S. pneumoniae blood isolates and 25 experimental mutants, we observed highly reproducible growth curves in nutrient-rich medium. The derived growth features were lag time, maximum growth rate, maximum density, and stationary-phase time before lysis. First, the pathogenicity of each growth feature was probed by comparing isolates from patients with and without marked preexisting comorbidity. Then, growth features were related to the propensity of causing severe manifestations of invasive pneumococcal disease (IPD). A high maximum bacterial density was the most pronounced pathogenic growth feature, which was also an independent predictor of 30-day mortality ( = 0.03). Serotypes with an epidemiologically higher propensity for causing meningitis displayed a relatively high maximum density ( < 0.005) and a short stationary phase ( < 0.005). Correspondingly, isolates from patients diagnosed with meningitis showed an especially high maximum density and short stationary phase compared to isolates from the same serotype that had caused uncomplicated bacteremic pneumonia. In contrast, empyema-associated strains were characterized by a relatively long lag phase ( < 0.0005), and slower growth ( < 0.005). The course and dissemination of IPD may partly be attributable to the pneumococcal growth features involved. If confirmed, we should tailor the prevention and treatment strategies for the different infection sites that can complicate IPD. Streptococcus pneumoniae is a leading infectious cause of deaths worldwide. To understand the course and outcome of pneumococcal infection, most research has focused on the host and its response to contain bacterial growth. However, bacterial epidemiology suggest that certain pneumococcal serotypes are particularly prone to causing complicated infections. Therefore, we took the bacterial point of view, simply examining growth features for hundreds of pneumococcal blood isolates. Their growth curves were very reproducible. Certain poles of pneumococcal growth features were indeed associated with specific clinical manifestations like meningitis or pleural empyema. This indicates that bacterial growth style potentially affects the progression of infection. Further research on bacterial growth and adaptation to different host environments may therefore provide key insight into pathogenesis of complicated invasive disease. Such knowledge could lead to more tailored vaccine targets or therapeutic approaches to reduce the million deaths that are caused by pneumococcal disease every year.
Topics: Humans; Infant; Meningitis; Pneumococcal Infections; Pneumococcal Vaccines; Serogroup; Serotyping; Streptococcus pneumoniae
PubMed: 35678554
DOI: 10.1128/spectrum.00050-22 -
Frontiers in Cellular and Infection... 2022is a Gram-positive bacterium and the leading cause of bacterial pneumonia in children and the elderly worldwide. Currently, two types of licensed vaccines are available... (Review)
Review
is a Gram-positive bacterium and the leading cause of bacterial pneumonia in children and the elderly worldwide. Currently, two types of licensed vaccines are available to prevent the disease caused by this pathogen: the 23-valent pneumococcal polysaccharide-based vaccine and the 7-, 10, 13, 15 and 20-valent pneumococcal conjugate vaccine. However, these vaccines, composed of the principal capsular polysaccharide of leading serotypes of this bacterium, have some problems, such as high production costs and serotype-dependent effectiveness. These drawbacks have stimulated research initiatives into non-capsular-based vaccines in search of a universal vaccine against In the last decades, several research groups have been developing various new vaccines against this bacterium based on recombinant proteins, live attenuated bacterium, inactivated whole-cell vaccines, and other newer platforms. Here, we review and discuss the status of non-capsular vaccines against and the future of these alternatives in a post-pandemic scenario.
Topics: Aged; Child; Humans; Immunization; Pneumococcal Infections; Pneumococcal Vaccines; Recombinant Proteins; Serogroup; Streptococcus pneumoniae; Vaccines, Conjugate
PubMed: 36225231
DOI: 10.3389/fcimb.2022.949469