Invasive pneumococcal disease in persons with predisposing factors is dominated by non-vaccine serotypes in Southwest Sweden

An economic evaluation of pneumococcal conjugate vaccines, PCV20 versus PCV15, for the prevention of pneumococcal disease in the Swedish pediatric population

In September 2023, 10-valent pneumococcal conjugate vaccine (PCV) was replaced by 15-valent PCV (PCV15) in Sweden's pediatric national immunization program. Following European approval of 20-valent PCV (PCV20) in March 2024, we assessed the cost-effectiveness of PCV20 versus PCV15, both under 2 + 1 schedule, among Sweden's pediatric population. A Markov state-transition model evaluated the economic and health benefits of PCV20 versus PCV15 among all ages over a 10-year time horizon. The base case adopted a Swedish payer perspective with an annual cycle length and 3.0% discount rate for costs and outcomes. Country-specific data informed population size, epidemiology, costs, and quality of life estimates. PCV15/PCV20 effect estimates were informed by PCV13 clinical effectiveness and impact studies plus PCV7 efficacy studies. Sensitivity analyses evaluated model robustness, including PCV20 under a 3 + 1 schedule. PCV20 was associated with higher quality-adjusted life year gains versus PCV15, averting an estimated 3,116 invasive pneumococcal disease cases 21,109 inpatient pneumonia cases, 6,618 outpatient pneumonia cases, and 36,209 otitis media cases, plus 3,281 pneumococcal disease-related deaths. PCV20 yielded substantial cost savings exceeding 5.4 billion SEK over a 10-year time horizon, primarily attributed to reduced direct medical costs due to improved health outcomes compared with PCV15. The findings confirmed the dominance of PCV20 in the base case, which remained robust across deterministic and probabilistic sensitivity analyses as well as scenario assessments. PCV20 was the dominant strategy versus PCV15 over 10 years. The broader serotype coverage of PCV20 suggests superior clinical and economic advantages over PCV15, warranting inclusion in Sweden's pediatric immunization program.

Invasive pneumococcal disease in Latin America and the Caribbean: Serotype distribution, disease burden, and impact of vaccination. A systematic review and meta-analysis

BACKGROUND

Invasive pneumococcal diseases (IPD) are associated with high morbidity, mortality, and health costs worldwide, particularly in Latin America and the Caribbean (LAC). Surveillance about the distribution of serotypes causing IPD and the impact of pneumococcal vaccination is an important epidemiological tool to monitor disease activity trends, inform public health decision-making, and implement relevant prevention and control measures.

OBJECTIVES

To estimate the serotype distribution for IPD and the related disease burden in LAC before, during, and after implementing the pneumococcal vaccine immunization program in LAC.

METHODS

Systematic literature review following Cochrane methods of studies from LAC. We evaluated the impact of the pneumococcal vaccine on hospitalization and death during or after hospitalizations due to pneumococcal disease and serotype-specific disease over time. We also analyzed the incidence of serotyped IPD in pneumococcal conjugate vaccine PCV10 and PCV13. The protocol was registered in PROSPERO (ID: CRD42023392097).

RESULTS

155 epidemiological studies were screened and provided epidemiological data on IPD. Meta-analysis of invasive diseases in children <5 years old found that 57%-65% of causative serotypes were included in PCV10 and 66%-84% in PCV13. After PCV introduction, vaccine serotypes declined in IPD, and the emergence of non-vaccine serotypes varied by country.

CONCLUSIONS

Pneumococcal conjugate vaccines significantly reduced IPD and shifted serotype distribution in Latin America and the Caribbean. PCV10/PCV13 covered 57-84% of serotypes in children under 5, with marked decline in PCV serotypes post-vaccination. Continuous surveillance remains crucial for monitoring evolving serotypes and informing public health action.

Streptococcus pneumoniae Serotype 23B Causing Asymptomatic Sinusitis Complicated by Endocarditis and Meningitis: Sequela of a Non-vaccine Serotype

We describe a rare case of a Streptococcus pneumoniae (S. pneumoniae) infection causing mitral valve endocarditis and bacterial meningitis in a previously healthy young adult male in his 20s who presented with altered mentation. Though our patient did not endorse any respiratory issues, we suspected the paranasal sinuses to have been the cryptic primary source of disseminated infection into the respiratory system and meninges due to incidental mucosal thickening being found on imaging. Blood and cerebrospinal fluid analyses and cultures revealed the proliferation of S. pneumoniae serotype 23B, despite our patient having previously received appropriate pneumococcal vaccinations in his childhood without delinquency. Ultimately, surgical replacement of the mitral valve, as well as a course of ceftriaxone, was indicated for this patient, in which full resolution of symptoms was achieved upon discharge.

The Molecular Approaches and Challenges of Streptococcus pneumoniae Serotyping for Epidemiological Surveillance in the Vaccine Era

Streptococcus pneumoniae (pneumococcus) belongs to the Gram-positive cocci. This bacterium typically colonizes the nasopharyngeal region of healthy individuals. It has a distinct polysaccharide capsule - a virulence factor allowing the bacteria to elude the immune defense mechanisms. Consequently, it might trigger aggressive conditions like septicemia and meningitis in immunocompromised or older individuals. Moreover, children below five years of age are at risk of morbidity and mortality. Studies have found 101 S. pneumoniae capsular serotypes, of which several correlate with clinical and carriage isolates with distinct disease aggressiveness. Introducing pneumococcal conjugate vaccines (PCV) targets the most common disease-associated serotypes. Nevertheless, vaccine selection pressure leads to replacing the formerly dominant vaccine serotypes (VTs) by non-vaccine types (NVTs). Therefore, serotyping must be conducted for epidemiological surveillance and vaccine assessment. Serotyping can be performed using numerous techniques, either by the conventional antisera-based (Quellung and latex agglutination) or molecular-based approaches (sequetyping, multiplex PCR, real-time PCR, and PCR-RFLP). A cost-effective and practical approach must be used to enhance serotyping accuracy to monitor the prevalence of VTs and NVTs. Therefore, dependable pneumococcal serotyping techniques are essential to precisely monitor virulent lineages, NVT emergence, and genetic associations of isolates. This review discusses the principles, associated benefits, and drawbacks of the respective available conventional and molecular approaches, and potentially the whole genome sequencing (WGS) to be directed for future exploration.

Reduced quantity and function of pneumococcal antibodies are associated with exacerbations of COPD in SPIROMICS

While hypogammaglobulinemia is associated with COPD exacerbations, it is unknown whether frequent exacerbators have specific defects in antibody production/function. We hypothesized that reduced quantity/function of serum pneumococcal antibodies correlate with exacerbation risk in the SPIROMICS cohort. We measured total pneumococcal IgG in n = 764 previously vaccinated participants with COPD. In a propensity-matched subset of n = 200 with vaccination within five years (n = 50 without exacerbations in the previous year; n = 75 with one, n = 75 with ≥2), we measured pneumococcal IgG for 23 individual serotypes, and pneumococcal antibody function for 4 serotypes. Higher total pneumococcal IgG, serotype-specific IgG (17/23 serotypes), and antibody function (3/4 serotypes) were independently associated with fewer prior exacerbations. Higher pneumococcal IgG (5/23 serotypes) predicted lower exacerbation risk in the following year. Pneumococcal antibodies are inversely associated with exacerbations, supporting the presence of immune defects in frequent exacerbators. With further study, pneumococcal antibodies may be useful biomarkers for immune dysfunction in COPD.

Parapneumonic effusions related to Streptococcus pneumoniae: serotype and disease severity trends from 2006 to 2018 in Bristol, UK

RATIONALE

Streptococcus pneumoniae epidemiology is changing in response to vaccination and some data suggest that empyema incidence is increasing. However, differences exist between the UK and US studies. We describe trends in the clinical phenotype of adult pneumococcal pleural infection, including simple parapneumonic effusions (SPE) in the pneumococcal conjugate vaccination (PCV) era.

OBJECTIVES

To determine whether there were differences in pneumococcal disease presentation and severity associated with pleural infection.

METHODS

A retrospective cohort study, all adults ≥16 years admitted to three large UK hospitals, 2006-2018 with pneumococcal disease. 2477 invasive pneumococcal cases were identified: 459 SPE and 100 pleural infection cases. Medical records were reviewed for each clinical episode. Serotype data were obtained from the UK Health Security Agency national reference laboratory.

RESULTS

Incidence increased over time, including non-PCV-serotype disease. PCV7-serotype disease declined following paediatric PCV7 introduction, but the effect of PCV13 was less apparent as disease caused by the additional six serotypes plateaued with serotypes 1 and 3 causing such parapneumonic effusions from 2011 onwards.Patients with pleural infection had a median survival 468 days (95% CI 340 to 590) vs 286 days (95% CI 274 to 335) in those with SPE. Pleural infection associated with frank pus had lower 90-day mortality than pleural infection without pus (0% vs 29%, p<0.0001). 90-day mortality could be predicted by baseline increased RAPID (Renal, Age, Purulence, Infection source, and Dietary factors) score (HR 15.01, 95% CI 1.24 to 40.06, p=0.049).

CONCLUSIONS

Pneumococcal infection continues to cause severe disease despite the introduction of PCVs. The predominance of serotype 1 and 3 in this adult UK cohort is in keeping with previous studies in paediatric and non-UK studies. Rising non-PCV serotype disease and limited impact of PCV13 on cases caused by serotypes 1 and 3 offset the reductions in adult pneumococcal parapneumonic effusion disease burden observed following the introduction of the childhood PCV7 programme.

Pneumococcal concentration and serotype distribution in preschool children with radiologically confirmed pneumonia compared to healthy controls prior to introduction of pneumococcal vaccination in Zanzibar: an observational study

BACKGROUND

The World Health Organization recommends pneumococcal vaccination (PCV) in the first year of life. We investigated pneumococcal serotypes in children with clinical or radiologically confirmed pneumonia and healthy controls prior to PCV13 vaccine introduction in Zanzibar.

METHODS

Children (n = 677) with non-severe acute febrile illness aged 2-59 months presenting to a health centre in Zanzibar, Tanzania April-July 2011 were included. Nasopharyngeal swabs collected at enrolment were analysed by real-time PCR to detect and quantify pneumococcal serotypes in patients (n = 648) and in healthy asymptomatic community controls (n = 161). Children with clinical signs of pneumonia according to the Integrated Management of Childhood illness guidelines ("IMCI pneumonia") were subjected to a chest-X-ray. Consolidation on chest X-ray was considered "radiological pneumonia".

RESULTS

Pneumococcal DNA was detected in the nasopharynx of 562/809 (69%) children (70% in patients and 64% in healthy controls), with no significant difference in proportions between patients with or without presence of fever, malnutrition, IMCI pneumonia or radiological pneumonia. The mean pneumococcal concentration was similar in children with and without radiological pneumonia (Ct value 26.3 versus 27.0, respectively, p = 0.3115). At least one serotype could be determined in 423 (75%) participants positive for pneumococci of which 33% had multiple serotypes detected. A total of 23 different serotypes were identified. One serotype (19F) was more common in children with fever (86/648, 13%) than in healthy controls (12/161, 7%), (p = 0.043). Logistic regression adjusting for age and gender showed that serotype 9A/V [aOR = 10.9 (CI 2.0-60.0, p = 0.006)] and 14 [aOR = 3.9 (CI 1.4-11.0, p = 0.012)] were associated with radiological pneumonia. The serotypes included in the PCV13 vaccine were found in 376 (89%) of the 423 serotype positive participants.

CONCLUSION

The PCV13 vaccine introduced in 2012 targets a great majority of the identified serotypes. Infections with multiple serotypes are common. PCR-determined concentrations of pneumococci in nasopharynx were not associated with radiologically confirmed pneumonia. Trial registration Clinicaltrials.gov (NCT01094431).