Pneumococcal Vaccine Research Articles

Community acquired pneumonia due to antibiotic resistant-Streptococcus pneumoniae: diagnosis, management and prevention.

A resurgence of pneumococcal pneumonia has been observed after a marked reduction in the early COVID-19 pandemic. Penicillin-nonsusceptible Streptococcus pneumoniae is regarded as a WHO priority pathogen. Overall antibiotic resistance rates in S. pneumoniae have increased due to increase in antibiotic consumption and changes in serotype distribution, partly driven by the rollout of pneumococcal vaccination. Isolates from pneumococcal pneumonia have higher resistance rates than those from invasive pneumococcal disease. New antibiotics have been approved for treatment of community-acquired pneumonia, and are active against multidrug-resistant S. pneumoniae. Pneumococcal vaccines in both children and adults are effective in reducing the burden of pneumococcal pneumonia in adults, though some circulating vaccine and nonvaccine serotypes are driving antibiotic resistance. Continual surveillance of serotype and resistance patterns of S. pneumoniae causing pneumonia in adult populations is important after the introduction of new pneumococcal vaccines. Novel pneumococcal vaccine platforms are needed to overcome the threats of serotype replacement and antibiotic resistance.

Economic Evaluation of Transitioning to the 20-Valent Pneumococcal Conjugate Vaccine in the Dutch Paediatric National Immunisation Programme.

In 2024, the vaccination strategy against pneumococcal disease in the Dutch paediatric population was changed from the 10-valent pneumococcal conjugate vaccine (PCV) (PCV10) to a 15-valent PCV (PCV15) under a 2 + 1 schedule. We aimed to assess whether switching from PCV15 under a 2 + 1 schedule to 20-valent PCV (PCV20) under a 3 + 1 schedule in the Dutch paediatric national immunisation programme (NIP) would yield economic savings and health benefits. A multiple-cohortpopulation model with an annual cycle and 10-year time horizon was adapted for the Dutch populationfrom a societal perspective. Discounting was set at 3.0% and 1.5% for costs and benefits, respectively. Medical and societal costs were calculated, along with cases of invasive and non-invasive pneumococcal disease, and quality-adjusted life years (QALY) for PCV15 and PCV20,from which, the incremental cost-effectiveness ratio (ICER) per QALY was calculated for PCV20 versus PCV15 to determine the economic benefits of PCV20. The model assumptions were tested in probabilistic and deterministic sensitivity analyses, as well as a series of scenario analyses. Both medical and societal cost of disease were substantially lower with PCV20 versus PCV15 (incremental cost-savings of €130,113,010 and €61,593,168, respectively), with total incremental cost-savings of €29,365,696 whenconsidering the cost of the vaccination programme. With an overall QALY gain of 33,232, the ICER per QALY placed PCV20 as the dominant strategy, as it was both more effective and less costly than PCV15. PCV20 was estimated to result in 57,657 fewer pneumococcal disease cases across invasive and non-invasive disease and 1561 fewer disease-related deaths. The sensitivity and scenario analyses demonstrated the robustness of the model results. This cost-effectiveness analysis demonstrated that switching from PCV15 2 + 1 to PCV20 3 + 1 in the Dutch paediatric NIP would reduce both the clinical burden and projected costs of pneumococcal disease over 10years.

Impact of the 10-valent pneumococcal conjugate vaccine (PCV10) on pneumococcal carriage in healthy children and children with acute otitis media and pneumonia: emergence of serotypes 3, 6C and 19A in Croatia.

In 2019, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced in the Croatian immunization programme, a first for this European PCV-naïve country. This study aimed to evaluate the impact of PCV10 on pneumococcal serotype distribution among asymptomatic children and children with pneumonia and/or acute otitis media. Cross-sectional studies were conducted before and after the PCV10 introduction, with nasopharyngeal swabs collected from 1500 healthy children under 48months of age. An additional 324 children under 18years with pneumonia and/or acute otitis media, from whom Streptococcus pneumoniae was isolated, were also included. Isolates were identified by conventional methods, serotyped by Quellung reaction, and tested for antimicrobial susceptibility using disk diffusion and gradient test methods. We report prevalence, absolute risk (prevalence) difference (RD) and relative risk (prevalence) ratio (RR) differences between exposed and control children. Carriage prevalence among healthy children increased from 19.9% to 28.7%, primarily due to a rise in non-vaccine serotypes (NVT). Adjusted probabilities for serotypes 6C (RR 3.18; 95% CI, 1.43-7.06), 11A (RR 2.8; 95% CI, 1.22-6.39), 19A (RR 4.18; 95% CI, 1.18-14.9) and 23A (RR 3.93; 95% CI, 1.87-8.24) were significantly higher in healthy exposed children. Prevalences of these serotypes were also higher in exposed children with pneumonia/acute otitis media. In this cohort, serotype 3 increased (RR 4.6; 95% CI, 2.02-10.3), becoming the leading post-PCV10 isolate in the overall studied population. Serotypes 3 and 19A were almost entirely responsible for complicated pneumonia cases for which the probability increased by 21-fold. Antimicrobial susceptibility remained similar across periods. In the early post-vaccine period significant increase of PCV10 vaccine-related serotypes (6C, 19A) was observed. Continued monitoring is also essential due to concerning rise of serotype 3 in patients with mucosal infections and a higher risk for complicated pneumonia.

A population-based study on the burden of hospitalized pediatric pneumococcal disease in Taiwan before and after the introduction of 13-valent pneumococcal conjugate vaccine into the childhood immunization program in 2015

BackgroundTo estimate the burden of invasive pneumococcal disease, non-bacteremic pneumococcal pneumonia, and acute otitis media before and after inclusion of the 13-valent pneumococcal vaccine (PCV13) into Taiwan’s Childhood Immunization Program in 2015.MethodsEpisodes of eligible children aged < 18 years hospitalized with invasive pneumococcal disease, non-bacteremic pneumococcal pneumonia, or acute otitis media between 1 January 2011 and 31 December 2019 were identified from the National Health Insurance Research Database. Annual hospitalized incidence rate, case fatality rate, and healthcare resource utilization and costs were estimated. Incidence time trends were assessed with interrupted time series analyses.Results1,284 invasive pneumococcal disease episodes, 25,074 non-bacteremic pneumococcal pneumonia episodes, and 23,139 acute otitis media episodes were identified. The overall annual incidence rates of invasive pneumococcal disease, non-bacteremic pneumococcal pneumonia, and acute otitis media were 3.31, 64.61, and 59.62 episodes per 100,000 person-years, respectively. Interrupted time series analyses results showed a significantly lower baseline incidence rate (incidence rate ratio [IRR]:0.58, p-value = 0.001) for invasive pneumococcal disease, and significantly higher baseline incidence rate (IRR:1.17, p-value < 0.001) for non-bacteremic pneumococcal pneumonia in the post-PCV13 period. Baseline incidence rates between the two periods were comparable for acute otitis media. A significant increase in trend of incidence rate was observed for all three diseases. Case fatality rate was 1.79%, 0.09%, and 0.00% for invasive pneumococcal disease, non-bacteremic pneumococcal pneumonia, and acute otitis media, respectively. Median length of hospitalization per inpatient visit was comparable between the two periods for invasive pneumococcal disease and non-bacteremic pneumococcal pneumonia, but significantly shorter in the post-PCV13 period for acute otitis media. In the post-PCV13 period, average total costs per episode was lower for invasive pneumococcal disease and non-bacteremic pneumococcal pneumonia, but higher for acute otitis media.ConclusionsResidual clinical and economic burden of pneumococcal diseases remained substantial after PCV13 inclusion into Taiwan’s Childhood Immunization Program. To further reduce the disease burden among children, additional research to investigate the cause of increasing trends of hospitalized invasive pneumococcal disease, non-bacteremic pneumococcal pneumonia and acute otitis media in the post-PCV13 era will be required.

Immunogenicity and Safety of the Higher Valent Pneumococcal Conjugated Vaccine Compared to the 13-Valent Pneumococcal Conjugated Vaccine in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract Introduction The immunogenicity of PCV15 and PCV20 in older adults was approved based on comparative data with PCV13, though their relative immunogenicity and safety in this population remain undetermined. A systematic review and meta-analysis were conducted to provide insights, addressing the lack of large-scale efficacy studies. Methods A phrase 2 or 3 randomized controlled trials evaluating immunogenicity of a single dose of either PCV15 or PCV20 in older adults by the opsonophagocytic assay (OPA) geometric mean titer (GMT) response at 1-month postvaccination compared to PCV13 were included in analysis. Results In total, eight trials were eligible. PCV15 group demonstrated superior immunogenicity compared to PCV13 among older adults (GMTR: 1.11, 95% CI: 1.02–1.20). The PCV20 group demonstrated non-inferiority (exceeded 0.5 at one-month post-vaccination) in immunogenicity compared to PCV13 (GMTR: 0.84, 95% CI: 0.81–0.87). The incidence of local and systemic reactions was higher in the PCV15 group compared to the PCV13 group, with risk ratios (RR) of 1.23 (95% CI: 1.14, 1.32) and 1.15 (95% CI: 1.02, 1.29), respectively. PCV20 are well tolerated and exhibit a comparable rate of local and systemic reactions to PCV13 group. Conclusions These findings support the immunogenicity and safety of PCV15 and PCV20 for pneumococcal vaccination in older adults. Given its superior immune response, PCV15 may address the gaps left by PCV13. Despite higher antibody levels, the clinical effectiveness of these vaccines remains uncertain. Ongoing surveillances are essential to evaluate both vaccines impact on remaining vaccine-type pneumococcal disease.

Impact of invasive and noninvasive pneumococcal diseases on adult populations: risk factors and vaccination status

BackgroundStreptococcus pneumoniae infections continue to pose significant health risks, particularly in adults with underlying conditions. This study assesses both demographic and clinical profiles of adult patients with invasive and non-invasive pneumococcal diseases, focusing on their vaccination status and outcomes.MethodsWe retrospectively analyzed clinical data from 217 adults diagnosed with pneumococcal infections at Eskişehir Osmangazi University Faculty of Medicine, a tertiary-care university hospital in Eskişehir, Türkiye, from January 2016 to November 2023. Cases meeting specific clinical and microbiological criteria were included. Logistic regression was utilized to identify key predictors of mortality.ResultsOf the 217 patients initially screened, 155 were included in the final analysis, comprising 75 cases of invasive and 80 cases of non-invasive disease. Notably, among those recommended for pneumococcal vaccination, only 20.6% were vaccinated, and strikingly, only 9% were vaccinated before infection. Significant correlations were observed between mortality and various factors, including age, comorbidities, bacteremia, invasive disease, and intensive care unit admissions. Mortality occurred in 39 (25.2%) of the patients, with notably higher risks among those with comorbidities and requiring intensive care.ConclusionPneumococcal infections continue to impose a significant health burden, particularly among older adults and those with pre-existing conditions. Our findings highlight the critical role of comorbidities and intensive care unit admissions in affecting patient outcomes, stressing the importance of timely interventions and enhanced health strategies to improve vaccination rates and overall outcomes in high-risk populations.

Delayed Transition to 20-Valent Pneumococcal Conjugate Vaccine in Pediatric National Immunization Programs: Forgone Public Health and Economic Benefit.

Despite the approval of a 20-valent pneumococcal conjugate vaccine (PCV20) for pediatric use in many regions globally, integrationof PCV20 into national immunization programs (NIPs) is delayed in some countries. We explored the public health and economic benefits forfeited by postponing transitions from lower-valent pneumococcal conjugate vaccines (PCVs) to PCV20. A targeted literature review (TLR) identified modeling studies comparing the public health and economic impact of PCV20 versus 13-valent PCV (PCV13) or 15-valent PCV (PCV15) in pediatric NIPs. Only studies with accessible models underwent data extraction and analysis. Foregone public health (pneumococcal disease cases/disease-related deaths) and economic (medical/non-medical costs) outcomes, defined as the projected incrementaldifferences between the outcomes associated with PCV20 and lower-valent PCVs, were calculated over 2years following PCV20 implementation (per year and month). Discount rates for all outcomes were adjusted to 0% given the short timehorizon and for consistencyacross analyses. The TLR identified models from 13 countries globally. The monthlyhealth benefits forgone due to delayed transitions from PCV13 to PCV20 ranged between 40 (Slovakia) and 1740 (Canada) pneumococcal disease cases avertedin the first year of delay across populations, increasing by between 1.5 (Sweden) and 15-16 times (Germany and Mexico) in the second year. Forgone cumulative disease-related deathsaverted ranged from 18 (Spain) to 2657 (Germany) and forgone cumulative direct medical cost-savings ranged from 930 thousand Euros (Portugal) to 146million Euros (Germany) due to delayed transitions from PCV13 to PCV20 over 2years. Similar, but slightly reduced, benefits were forfeited with delayed transitions from PCV15 to PCV20. Delays in implementing PCV20 into pediatric NIPs were projected to have substantial negativepublic health and economic consequences. These results underscore the necessity for national immunization technical advisory groups, policymakers, health organizations, and manufacturers to accelerate replacement of lower-valent standard-of-care PCVs with PCV20.

Nasopharyngeal Carriage and Antibiotic Resistance in Children With Sickle Cell Disease: The DREPANOBACT French Multicenter Prospective Study.

Children with sickle cell disease (SCD) are susceptible to invasive bacterial infections, particularly those caused by Streptococcus pneumoniae. Data concerning nasopharyngeal carriage remain scarce in this population at high risk of resistant bacteria owing to antibiotic pressure and frequent hospitalizations. We conducted this prospective trial, DREPANOBACT, in 7 French hospitals to assess the nasopharyngeal carriage rate for S. pneumoniae among children with SCD aged 6 months-15 years between September 2022 and April 2024. The secondary aim was to determine the serotype distribution and proportion of penicillin nonsusceptible S. pneumoniae isolates and the carriage and antibiotic resistance rates for Staphylococcus aureus, Moraxella catarrhalis and Haemophilus influenzae. In total, 300 children were enrolled [median age, 8 years (interquartile range: 4-12 years)]. S. pneumoniae carriage accounted for 32 cases (11%), including 21 penicillin nonsusceptible S. pneumoniae strains (66%). The main serotypes were 23A (n = 4), 35B (n = 4), 11A (n = 3) and 15C (n = 3). Overall, 75% of the serotypes were non-13-valent pneumococcal conjugate vaccine (PCV) serotypes, with 19% and 53% covered by PCV20 and PCV21, respectively. The carriage rates for S. aureus, M. catarrhalis and H. influenzae were 31%, 17% and 11%, respectively. Methicillin resistance was observed in 5% of S. aureus strains. Age ≤5 years was significantly associated with S. pneumoniae, M. catarrhalis, and H. influenzae carriage, while age ≥11 years was associated with S. aureus carriage. Surveillance of nasopharyngeal carriage in children with SCD is warranted to monitor changes in predominant serotypes and resistance patterns.

Systematic literature review of cost-effectiveness analyses of adult 15- and 20-valent pneumococcal vaccines.

The economic and public health benefits of adult pneumococcal vaccines vary across countries due to different epidemiology and costs. We systematically reviewed and summarized findings and assumptions of cost-effectiveness analyses (CEA) of the recently introduced 15- and 20-valent pneumococcal conjugate vaccines (PCV15 and PCV20) in adults. We performed a systematic search for CEA studies of PCV15 and/or PCV20 versus existing strategies via PubMed, EMBASE, CEA Registry, EconLit, HTA Database, and NITAG resource center through April 23, 2024. Study characteristics, methods, assumptions, and findings were extracted independently by two reviewers; quality was assessed using ECOBIAS. Results were synthesized qualitatively to summarize key attributes and conclusions. Of 137 identified records, 26 studies were included; the majority (24/26) concerned high-income countries. All employed static Markov-type models comparing higher-valent PCVs used alone or in combination with 23-valent pneumococcal polysaccharide vaccine (PPSV23) to current recommendations (PPSV23 alone, PCV13 alone, PCV13+PPSV23, no vaccination). Most studies (22/26) concluded PCV20 used alone was cost-saving (dominant) or cost-effective compared to other adult pneumococcal strategies (PPSV23 alone, PCV13±PPSV23, PCV15±PPSV23, or no vaccination). PCVs were generally assumed to have serotype-specific effectiveness equal to PCV13 efficacy in the pivotal trial, though four studies used estimates from a Delphi panel; protection was assumed to last between 10 and 20years. PPSV23 was assumed to have lower effectiveness against non-bacteremic pneumonia and shorter duration of protection. Herd effects from higher-valent PCVs in childhood (12/26), serotype replacement (2/26), or both (1/26) were included in half (13/26) of studies, which attenuated adult vaccine impact. Most studies were assessed as low risk of bias; five abstracts did not provide sufficient information for assessment. Current evidence indicates that 20-valent PCV used alone is likely to be cost-effective or dominate other adult pneumococcal strategies. Future research is needed to address remaining uncertainties in assumptions and to support evidence-based policymaking.

Influenza and pneumococcal vaccine coverage among adults hospitalised with acute respiratory infection in France: a prospective cohort study.

This study aimed to estimate influenza and pneumococcal vaccination coverage (VC) among adults hospitalised with severe acute respiratory infections (SARI) in France from 2016 to 2022 and to analyse factors associated with vaccination. We analysed data from a prospective multicentre study, in adults hospitalised with SARI. A descriptive and comparative analysis of influenza and pneumococcal VCs was conducted, along with multivariate logistic regression to identify factors associated with vaccination. We included 4614 patients; 88% (4080/4614) had an indication for influenza vaccination. Among them, 2181/4080 (53%) were vaccinated against influenza. Factors associated with vaccination included age ≥65 years (adjusted odds ratio [aOR] 3.05; 95% CI 2.63 - 3.55), chronic respiratory diseases (aOR 1.38; 95% CI 1.20 - 1.59). Pneumococcal vaccination status was available for 90% (4142/4614) patients, among whom 71% (2920/4142) had an indication for vaccination. Pneumococcal VC was 19% (551/2920). Factors associated with vaccination were chronic respiratory disease (aOR 2.74; 95% CI 2.22 - 3.40) and immunocompromising conditions other than malignancies. VC for each vaccine did not increase overtime. Among 3247 patients eligible for both vaccines 13% received both. In this high-risk population, VC was low, especially pneumococcal vaccines. Improved vaccination recommendation strategies and communication are needed.

Vaccination Coverage and Attitudes in Children and Adults on Biologic Therapies: Cocooning Strategies, Undervaccination Factors and Predictors of Favorable Attitudes

Background: Infections pose a significant risk of morbidity and mortality to patients on biologics, with the vaccination of both patients and their close contacts serving as a key preventive measure. Despite its importance, there are limited data on the vaccination coverage for this group, and no studies have examined the vaccination status of patients’ close contacts. Objectives: To assess vaccination rates among patients on biologics and their household contacts, identifying reasons for inadequate vaccination and examining factors influencing vaccination status and attitudes is crucial. Methods: A cross-sectional study was conducted from September 2022 to February 2023 at the two hospitals in Heraklion, Crete, including adult and pediatric patients on biologics. Data were collected through medical records and interviews and analyzed using Microsoft Excel 2016 and MedCalc2006. Results: Among the 446 adults, vaccination rates were as follows: 83% for COVID-19, 73.8% for influenza, 64.5% for the pneumococcal conjugate vaccine, 29.6% for the pneumococcal polysaccharide vaccine, and 4% for Tdap. Among the 26 children included, those with basic immunization schedule coverage exceeded 96%, but rates for the vaccines usually administered at adolescence were lower (Tdap: 47.8%, HPV: 42.1%, MenACWY: 66.7%). COVID-19 vaccination was at 38.5%. Regarding the additional vaccines recommended due to treatment-induced immunosuppression, 69.2% of pediatric patients received the annual influenza vaccine, while only 19.2% received the pneumococcal polysaccharide vaccine. Household contacts demonstrated low vaccination rates (&lt;59%), except for COVID-19 (81%). Female gender (p &lt; 0.007) and older age (by 1 year, p &lt; 0.001) were associated with favorable attitudes and higher coverage in adults, while in pediatric patients, no statistically significant associations were found. A lack of physician recommendation was the primary reported reason for not being vaccinated. Conclusions: Significant vaccination gaps exist among patients on biologics and their close contacts, largely due to inadequate physician recommendations. Raising awareness and strengthening healthcare provider roles are essential to improve coverage in this high-risk group.

Immunogenicity of yellow fever vaccine co-administered with 13-valent pneumococcal conjugate vaccine in rural Gambia: A cluster-randomised trial.

Because booster doses of pneumococcal conjugate vaccine (PCV) may be given at a similar time to yellow fever vaccine (YF), it is important to assess the immune response to YF when co-administered with PCV. This has been investigated during a reduced-dose PCV trial in The Gambia. In this phase 4, parallel-group, cluster-randomized trial, healthy infants aged 0-10weeks were randomly allocated to receive either a two-dose schedule of PCV13 with a booster dose co-administered with YF vaccine at age 9months (1+1 co-administration) or YF vaccine administered separately at age 10months (1+1 separate) or the standard three early doses of PCV13 with YF vaccine at age 9months (3+0 separate). Blood samples were collected 28-35days post-vaccination and YF neutralizing antibody (NA) titres were measured. Proportions with seroprotective YF NA titres≥1:8 were calculated with 95% confidence intervals (CI). Non-inferiority was demonstrated if the lower limit of the CI for the difference in proportions between the co-administration and separate groups was greater than-10%. Forty-eight, 66, and 98 participants enrolled in 3+0 separate, 1+1 co-administration, and 1+1 separate groups respectively had NA results. Per protocol analysis of the 3+0 separate, 1+1 co-administration, 1+1 separate, and the combined 1+1 separate and 3+0 separate groups found that 81%, 85%, 92%, and 88% of participants respectively had YF NA titres ≥1:8. Results were similar with analysis by intention-to-treat. The difference in proportions comparing 1+1 co-administration and 1+1 separate groups was -7% (95% CI, -18% to 3%). The difference between 1+1 co-administration and 3+0 separate groups was 4% (95% CI, -10% to 15%). There was no statistical difference in the YF seroresponse when the YF vaccine was co-administered with PCV or administered separately. No evidence was found of the non-inferiority of the seroresponse to YF vaccine when co-administered with PCV13. The levels of YF NA attaining seroprotection (NT ≥1:8) were high in all groups. PCV13 co-administered with YF vaccine at 9months does not affect seroresponse to YF vaccine. http://www.isrctn.org/ - ISRCTN72821613.

Receipt of respiratory vaccines among patients with heart failure in a multicenter health system registry.

Heart failure affects people of all ages and is a leading cause of death for both men and women in most racial and ethnic groups in the United States. Infections are common causes of hospitalizations in heart failure, with respiratory infections as the most frequent diagnosis. Vaccinations provide significant protection against preventable respiratory infections. Despite being an easily accessible intervention, prior studies suggest vaccines are underused in patients with heart failure. An observational study of 5089 adults with heart failure was conducted using data from an integrated, multicenter, academic health system in Southern California from 2019 to 2022. Logistic regression models were used to determine the rates of influenza, pneumococcal, and COVID-19 vaccination among a population of patients with heart failure (heart failure preserved ejection fraction [HFpEF], heart failure mildly reduced ejection fraction [HFmrEF], and heart failure reduced ejection fraction [HFrEF], and identify whether heart failure phenotype is associated with vaccination status. Vaccination rates varied between influenza, pneumococcal, and COVID-19 vaccines. Of the three respiratory vaccines, 58.0% of patients had received an influenza vaccine, 76.2% had received a pneumococcal vaccine, and 83.3% had received a COVID-19 vaccine. There were no sex-based differences by vaccination status. Differences were seen within age, race/ethnicity, insurance type, whether the patient was a member of an Accountable Care Organization (ACO), primary language, Social Vulnerability Index (SVI) score, clinician type, and number of comorbidities. Patients with HFpEF and HFmrEF had higher vaccination rates than HFrEF. In adjusted models, patients with HFrEF had lower odds of being vaccinated for influenza (aOR=0.75, 95% CI=0.66-0.86), pneumococcal (aOR=0.65, 95% CI=0.55-0.75), and COVID (aOR=0.74, 95% CI=0.62-0.89) compared to patients with HFpEF. Patients with HFrEF had the lowest levels of respiratory vaccination compared to other specified heart failure categories. Interventions are needed to increase vaccination education and offerings, especially to patients with HFrEF.

Pneumococcal Vaccination Does Not Fully Protect Against Otogenic Meningitis in Patients with Tegmen Defects

Pneumococcal Vaccination Does Not Fully Protect Against Otogenic Meningitis in Patients with Tegmen Defects

Nasopharyngeal carriage of Streptococcus pneumoniae among children and their household members in southern Mozambique five years after PCV10 introduction.

Streptococcus pneumoniae is an important cause of pneumonia, sepsis, and meningitis, which are leading causes of child mortality. Pneumococcal conjugate vaccines (PCVs) protect against disease and nasopharyngeal colonization with vaccine serotypes, reducing transmission to and among unvaccinated individuals. Mozambique introduced 10-valent PCV (PCV10) in 2013. In 2017-2019, 13-valent PCV (PCV13) replaced PCV10, and in September 2019 the schedule changed from three primary doses to two primary doses and a booster; the booster-containing schedule may increase indirect effects. We examined pneumococcal carriage in Mozambique to establish a baseline for estimating the impact of policy changes and to estimate the long-term impact of PCV10 in children aged <5years. We calculated prevalence of carriage of PCV10 serotypes and the 3 additional PCV13 serotypes ('PCV13-unique') among children aged <5years and their household members in southern Mozambique, between October 2018 and July 2019. Nasopharyngeal swabs were cultured, and isolates underwent Quellung serotyping. For children, we compared these "long-term post-PCV10" data with prior surveys ("pre-PCV" (2012-2013) and "post-PCV10" (2015-2016)) that used the same methods. In 2018-2019, among 1319 children aged under five years, 1064 (80.7%) were colonized with pneumococcus, among 614 children aged 5-<18years, 355 (57.8%) were colonized, and among 804 adults (aged ≥18years), 285 (35.4%) were colonized. The most frequently observed serotypes were 19A (n=154, 8.5% of isolates) and 6A (n=107, 5.9%), both PCV13-unique serotypes. Overall carriage prevalence among children under five years remained stable at approximately 80% across the carriage studies conducted between 2012 and 2019; between 2015 and 2016 and 2018-2019, the prevalence of PCV10-type carriage declined from 17.7% to 10.1%. Despite substantial declines in PCV10-type carriage initially following vaccine introduction, the continued circulation of PCV10 serotypes and relative high prevalence of PCV13-unique serotypes underscore the need to understand the impact of policy changes on pneumococcus transmission.

A comprehensive analysis of serotype-specific invasive capacity, clinical presentations, and mortality trends of invasive pneumococcal disease.

Pneumococcal conjugate vaccines (PCV) reduced invasive disease, but the overall prevalence of pneumococcal nasopharyngeal colonization among children has not changed significantly. Our knowledge of which serotypes, once colonized, hold a higher likelihood to cause invasive disease is limited. Serotype-specific invasive capacity (IC) of Streptococcus pneumoniae was estimated using an enhanced population-based invasive pneumococcal disease (IPD) surveillance in children <7years of age in Massachusetts and surveillance of nasopharyngeal (NP) colonization in selected Massachusetts communities in corresponding respiratory seasons. Serotype-specific IC was calculated by dividing the annual incidence of IPD by the carriage prevalence for each serotype. Serotype-specific relationship between NP carriage and IPD was evaluated by year, age group (<24months vs 24-84months), pre-PCV13 (2003/04, 2006/07, 2008/09) vs post-PCV13 (2010/11, 2013/14, 2015/2016) periods, clinical presentation, and outcome. A total of 293 IPD and 1602 NP isolates were included in the analysis. Most common IPD serotypes were 19A (34.1%), 7F (9.2%), 15BC (8.9%), 3 (5.8%), and 22F (4.8%). Serotypes 18C, 38, 7F, 19A, 3, 22F, and 33F displayed a higher propensity to cause IPD once colonizing the nasopharynx compared to 11A, 35B, 6C, and 21. Serotype-specific IC was generally lower in children older than 24months. During the study period, we observed shifts in the dominant serotypes in relation to IC as well as changes between pre- to post-PCV13 era. Except for serotypes 14, 6A, 7F, 11A, 23A, 20, 35F, 7C, 6C and 15F all serotypes presented primarily as bacteremia. Pneumonia was attributed to serotypes 14 and 20; serotypes 35B, 23B, and 11A were responsible for the highest percentage of deaths. This study highlights the need for continued serotype-specific surveillance to better understand the disease potential of emerging serotypes and to guide optimal vaccination strategies.

The clinical range and management of spontaneous rupture of the pathological malarial spleen (SRPMS): A short case series from Sudan.

Spontaneous rupture of the pathological malarial spleen (SRPMS) is a rare condition with a mortality rate among travelers of approximately 38%, whereas it was around 10 % for local citizens. The mortality rate for overwhelming post-splenectomy sepsis was reported to be about 50 %. A retrospective study was conducted from febraury2022 to July 2022. Baseline clinical presentations, management, and outcomes were recorded for analysis. We present a brief series of eight patients with (SRPMS). Of them, five had successful conservative treatment, while three underwent splenectomy. Only one of them received Pneumococcal vaccine. SRPMS is a rare complication of malaria infection, it can be managed non-surgically, and splenectomy is necessary for unstable patients. Post-surgery vaccination remains crucial to prevent severe infections.

P-18. Incidence of Pneumococcal Disease and Vaccination Coverage among US Adults by Age and Risk Groups

Abstract Background Older adults and those with underlying medical conditions are at increased risk for illness, hospitalization, and death from pneumococcal disease (PD). The CDC currently recommends pneumococcal vaccination for adults ≥65 years and adults ≥19 years with underlying medical conditions who are at greater risk of PD. Identifying differences in pneumococcal vaccination coverage (VCR) and disease incidence is necessary to develop and implement strategies to improve VCR. We estimated VCR and incidence of PD, by age and risk group, among adults ≥18 years in the United States from 2017-2020. Methods This was a retrospective study of administrative claims data from Merative® MarketScan® Commercial Claims and Encounters Database. From 2017-2020, annual incidence rates of invasive pneumococcal disease (IPD), non-bacteremic pneumococcal pneumonia (NBPP) and all-cause pneumonia (ACP) were estimated by age group (18-49, 50-64, ≥65 years) and risk group (healthy, with chronic medical conditions (CMC) and with immunocompromising conditions (IC)) among adults with at least 2.5 years of continuous enrollment. Adults were considered vaccinated if they had at least one pneumococcal vaccine within 2 prior years to their index date. The percentage of pneumococcal vaccination was reported annually from 2017-2020. Results From 2017-2020, there were approximately 9-10 million patients annually in the study population. Less than 25% of US adults recommended for pneumococcal vaccination were vaccinated (Figure 1). Vaccination rates were highest among those ≥65 years (Figure 1). Annual incidence rates per 100,000 person-years decreased from 2017 to 2020 for IPD, NBPP and ACP (Figure 2). Each year, the incidence of PD was consistently higher among those ≥65 years, and those with IC or CMC. There was a decrease in the incidence of PD in 2020, coinciding with the COVID-19 pandemic. Conclusion Despite ACIP recommendations, vaccination rates remain low in those recommended to receive a pneumococcal vaccine, specifically among older adults and those with underlying conditions. This analysis underscores the opportunity to improve VCR and prevent PD in US adults, especially those at greatest risk. Disclosures M. Doyinsola Bailey, PHD, MPH, Merck &amp; Co., Inc., Rahway, NJ, USA: Employee|Merck &amp; Co., Inc., Rahway, NJ, USA: Stocks/Bonds (Public Company) Yi-Ling Huang, PhD, Merck: Stocks/Bonds (Public Company) Salini Mohanty, DrPH, MPH, Merck &amp; Co., Inc.: Employee|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company) Kelly D. Johnson, PhD, Merck &amp; Co., Inc.: Employee|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company) Nicole Cossrow, PhD, Merck: Stocks/Bonds (Public Company)

P-12. Evaluating the Epidemiological Impact of Lowering the Recommended Age for Adult Pneumococcal Vaccination in the United States

Abstract Background In the United States, there are two age-based pneumococcal vaccine recommendations – children aged 0-2 years and adults aged 65+ years. Adults aged 50-64 are recommended to receive a pneumococcal vaccine if at increased risk of pneumococcal disease; disease burden in this age groups represents the third highest level of pneumococcal disease. PCV20, a 20-valent PCV, and PCV15 are higher valent vaccines currently approved for adults. V116, an investigational adult specific PCV is being developed to specifically broaden protection in the adult population, by including key serotypes in currently licensed vaccines and 8 unique serotypes responsible for ∼30% of pneumococcal disease in adults in the US. Cumulative IPD cases in a 10-year projection period for V116 and PCV20. Methods We evaluated the impact of lowering the pneumococcal adult age-based vaccine recommendations in the United States to individuals aged 50+ years using a model that tracked age- and serotype-specific Streptococcus pneumoniae (SP) transmission. The model was calibrated to historical age- and serotype-specific invasive pneumococcal disease (IPD) data in the United States spanning 2000-2019. We evaluated the impact of lowering the recommended vaccination age in adults to 50+ years-old with V116. For projections we maintained an 80/20 coverage of PCV20/PCV15 in 82% of children and assumed a VCR of 57% for adults aged 65+. In the 50+ years old scenario, we reduced VCR to 46%, which was the age-specific tetanus rates for individuals aged 50-64 years-old multiplied by the reduction in uptake from the Shingrix vaccine when the recommended age was lowered. These adult VCR values assume a PCV was received in the last 10 years. Results Reducing the adult recommended vaccination age to 50+ years with the reduced VCR, led to similar overall reductions in IPD incidence when compared to maintaining the vaccination age at 65+ years (Table 1). The additional reductions in IPD in 50-64 year-olds was negated by the increase in cases in individuals aged 65+ years, due to vaccine waning. Conclusion If the recommended pneumococcal vaccination age for adults is reduced, additional efforts must be made to minimize the reduction of VCR, otherwise total IPD incidence will be similar to the current 65+ year-old age recommendation due to vaccine waning. Disclosures Kevin Bakker, PhD, Merck &amp; Co., Inc.: Grant/Research Support|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company) Giulio Meleleo, PhD, Merck &amp; Co., Inc.: Vendor Oluwaseun Sharomi, MSc, PhD, Merck &amp; Co., Inc.: Full time employee|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company) Robert Nachbar, PhD, Merck &amp; Co., Inc.: US 7,219,020, US 5,292,741|Merck &amp; Co., Inc.: Vendor|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company) Rachel Oidtman, PhD, Merck &amp; Co., Inc.: Full time employee|Merck &amp; Co., Inc.: Stocks/Bonds (Public Company)

P-61. Perceived Importance of Adult Immunizations among HIV Providers in New Orleans, Louisiana

Abstract Background Immunizations are key to primary care for people with HIV (PWH). Unfortunately, immunization rates among PWH are reportedly low. In addition to patients’ preferences, limited time and acute issues, knowledge gap and beliefs about vaccine among clinicians could negatively impact their recommendations, which would ultimately affect vaccine uptake for PWH. Table 1 Survey results about perceived importance of vaccines of interest for people with HIV in different age groups prior to (pre-test) and after (post-test) education session Methods This was a clinical quality improvement project at HIV Outpatient Program (HOP) at University Medical Center, New Orleans in 2023. A pretest survey was conducted to evaluate providers’ perceived importance of the vaccines of interest for PWH in different age groups: aged 19 to 26, 27 to 45, and 65 or above. Participants were asked to rank the vaccines on a scale of 0 to 3: 0 means the vaccine is not indicated; 1 means the vaccine is optional; 2 means the vaccine is important; and 3 means the vaccine is very important. The pre-test was followed by an educational session to review updates of adult immunizations tailored to PWH. Following this a post-test survey was collected to assess changes in perceived importance among participants. Image 1 Perceived importance of immunizations among PWH aged 19 to 26 Results 12 physicians participated in this study. Participants’ perceived importance of most immunizations improved after education (table 1 and figure 1-3). The perceived most important vaccines after education, defined by a score of 2.5 or above, were: meningococcus, hepatitis B, hepatitis A, HPV, and pneumococcus vaccines among PWH aged 19 to 26; hepatitis B, pneumococcus, hepatitis A, meningococcus, and COVID-19 vaccines among PWH aged 27 to 45; pneumococcus, COVID-19, herpes zoster, hepatitis B, and influenza vaccines among PWH aged 65 or above. There was a statistically significant increase in the perceived importance of HPV vaccines among PWH aged 19 to 26 after education. In addition, all participants thought pneumococcus vaccine is very important (score of 3 in both pre and posttests) for PWH aged 65 or above. Image 2 Perceived importance of immunizations among PWH aged 27 to 45 Conclusion Educational training among HIV providers raised awareness of the importance of immunization. After the training session, we noticed a 46% increase in total number of PWH aged 19 to 26 who completed HPV vaccine series. Similar approach could be implemented to general practitioners to improve vaccine uptake in primary care. Image 3 Perceived importance of immunizations among PWH aged 65 or above Disclosures All Authors: No reported disclosures