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

Study of pediatric invasive pneumococcal disease in the 13-pneumococcal conjugated vaccine era

BACKGROUND

Invasive pneumococcal disease (IPD) remains a significant concern among children under 5, despite vaccination efforts. This study assessed IPD prevalence and associated risks in pediatric population.

METHODS

An observational, retrospective, multicenter study in Comunidad Valenciana, Spain, of IPD cases in children under 13 from January 2012 to September 2022. Data from the CV Microbiology Surveillance Network (RedMIVA) and medical records were reviewed.

RESULTS

A total of 379 IPD cases in 377 patients were analyzed, predominantly males (54.11 %) under 5 (81.17 %). PCV13 vaccination notably reduced PCV13-serotypes IPD (p=0.0002), except serotype 3. Pneumonia was common, with half having underlying conditions (50.40 %). Worse outcomes occurred in patients with neurological disorders (ANOVA, p=0.57). Vaccine failures often involved underlying conditions (63 %) and serotypes 3 and 19A. Immunodeficiencies may relate to recurrent IPD, but evidence is limited.

CONCLUSION

Despite vaccination, IPD still impacts children, influenced by immunological status, affecting severity and mortality.

A Profile of Adult Severe Acute Respiratory Syndrome Coronavirus 2 Pneumonia Patients According to Pneumococcal Vaccination Status

Certain patient profile characteristics, such as preexisting medical conditions, can modify the risk of developing SARS-CoV-2 pneumonia among adults vaccinated and not vaccinated against pneumococcal disease. This retrospective cohort study aimed to quantify the risk of pneumonia caused by SARS-CoV-2 among individuals from 15 to 64 years old with and without pneumococcal vaccination in Spain during the 2020-2021 influenza season and establish a risk profile of patients more likely to develop SARS-CoV-2 pneumonia. Data (demographic information, patient medical history, and lifestyle habits) were gathered both directly from the patient via personal interview and by reviewing electronic medical records. In an adjusted analysis for pneumococcal vaccinated patients, visits to hospital outpatient clinics were protective while visits to primary health care services, being widowed, obese, and not using masks in outdoor open spaces were identified as risk factors. For patients who had not received a pneumococcal vaccine, visits to hospital outpatient clinics were protective, while being overweight or obese, alcohol consumption, and not using masks in outdoor open spaces were identified as risk factors. Concerning comorbidities, in the pneumococcal vaccinated group none were found to be protective but having diabetes or other respiratory diseases were identified as risk factors. In the unvaccinated group, undergoing immunosuppressive treatment and having metastatic tumors were protective factors, while cerebrovascular disease and obesity with a BMI ≥ 40 were risk factors. A similar risk profile for developing SARS-CoV-2 pneumonia in pneumococcal vaccinated and non-vaccinated individuals was found. Generally, vaccinated individuals had a lower risk of developing SARS-CoV-2. The findings suggest that vaccination against S. pneumoniae could prevent and reduce SARS-CoV-2 pneumonia. Additionally, this study has identified individuals with other medical conditions, such as obesity, underweight, diabetes, and a history of respiratory diseases, who are at an increased risk of developing SARS-CoV-2 pneumonia and could benefit from vaccination and supervision.

[Epidemiology of pneumococcal pneumonia among middle-aged and older adults in Catalonia, 2017-2018]

OBJECTIVE

To analyse population-based incidence and lethality of pneumococcal pneumonia (PP) requiring hospitalisation among Catalonian adults after universal vaccination implementation in infants.

DESIGN

Population-based cohort study.

SETTING

Primary care/hospital, Catalonia.

PARTICIPANTS

2,059,645 individuals ≥50 years old affiliated to the Institut Catala de la Salut retrospectively followed between 01/01/2017 and 31/12/2018.

MAIN OUTCOME MEASURES

The Catalonian information system for the development of research in primary care (SIDIAP, Sistema de Información para el Desarrollo de la Investigación en Atención Primaria) was used to establish baseline characteristics and risk-strata of cohort members at study start: low-risk (immunocompetent persons without risk conditions), intermediate-risk (immunocompetent persons with at-risk condition) and high-risk (immunocompromising conditions). PP requiring hospitalisation among cohort members across study period were collected from CMBD (Conjunto Mínimo Básico de Datos) discharge data of 64 reference Catalonian hospitals.

RESULTS

An amount of 3592 episodes of HPP were observed, with an incidence density of 90.7 cases per 100,000 person-years (95% CI: 85.2-96.5), being 11.9 bacteremic (95% CI: 10.8-13.1) and 78.8 non-bacteremic (95% CI: 74.0-83.8). Incidence rates substantially increased by age (37.3 in 50-64 years vs. 98.3 in 65-79 years vs. 259.8 in ≥80 years) and baseline-risk stratum (42.1, 120.7 and 238.6 in low-, intermediate- and high-risk stratum, respectively). Overall case-fatality rate was 7.6% (10.8% in invasive cases vs. 7.1% in non-invasive cases; pP=.004). In multivariable analyses, high-risk stratum and oldest age were the strongest predictors for invasive and non-invasive cases, respectively.

CONCLUSION

Incidence and lethality of PP remained moderate among adults >50 years in Catalonia during 2017-2018 (earlier period after universal vaccination introduction for infants).

Immunisation schedule of the Spanish Association of Paediatrics: 2023 Recommendations

As it does every year, the CAV-AEP publishes the update of its recommendations for the use of vaccines in children, adolescents and pregnant women residing in Spain. The 2 + 1 schedule is maintained in infants (at 2, 4 and 11 months), including preterm infants, with the hexavalent vaccine (DTaP-IPV-Hib-HB) and the pneumococcal 13-valent conjugate vaccine. A booster dose with DTaP-IPV is needed at 6 years for those who received the 2 + 1 series with hexavalent vaccine as infants, in addition to 1 dose of dTap in adolescence. Routine vaccination of pregnant women with a dose of dTap is recommended in each pregnancy, preferably between weeks 27 and 32 of gestation, although can be given from 20 weeks if there is risk of preterm delivery. All infants should receive the rotavirus vaccine (2-3 doses) and the 4CMenB vaccine (2 + 1 series). All children aged 6-59 months should be vaccinated against influenza each year. The MenACWY vaccine should be given routinely at 12 months of age and in adolescence between ages 12 and 18 years. The recommendations for the MMR vaccine (12 months and 3-4 years) and varicella vaccine (15 months and 3-4 years) also remain unchanged, using the MMRV vaccine for the second dose. Recommendations for the use of SARS-CoV-2 vaccines in the paediatric age group will be updated periodically on the CAV-AEP website. The HPV vaccine is indicated in all adolescents, regardless of sex, at age 12 years. Novelties include the recommendation of routine administration of nirsevimab to neonates and infants aged less than 6 months for passive immunization against RSV, and the recommendations regarding the hexavalent vaccine are consolidated in a single section.

Targeted Transcriptomic Screen of Pneumococcal Genes Expressed during Murine and Human Infection

The advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease. Alternative strategies, using genetically conserved proteins as antigens, have been evaluated preclinically and clinically for years, so far unsuccessfully. One possible explanation for the failure of these efforts is that the choice of antigens may not have been sufficiently guided by an understanding of the gene expression pattern in the context of infection. Here, we present a targeted transcriptomic analysis of 160 pneumococcal genes encoding bacterial surface-exposed proteins in mouse models, human colonization, and human meningitis. We present the overlap of these different transcriptomic profiles. We identify two bacterial genes that are highly expressed in the context of mouse and human infection: SP_0282, an IID component of a mannose phosphotransferase system (PTS), and SP_1739, encoding RNase Y. We show that these two proteins can confer protection against pneumococcal nasopharyngeal colonization and intraperitoneal challenge in a murine model and generate opsonophagocytic antibodies. This study emphasizes and confirms the importance of studies of pneumococcal gene expression of bacterial surface proteins during human infection and colonization and may pave the way for the selection of a protein-based vaccine candidate.

Pharmacokinetic/pharmacodynamic evaluation of the antimicrobial therapy of pneumococcal invasive disease in adults in post-PCV13 vaccine period in Madrid, Spain

The objective of our study was to evaluate by pharmacokinetic/pharmacodynamic (PK/PD) analysis, if the antimicrobials used for the treatment of invasive pneumococcal disease (IPD) in adults, including meningitis, are adequate considering the susceptibility profile of S. pneumoniae in Spain after the implantation of PVC13 vaccine. Pharmacokinetic parameters of benzylpenicillin and cefotaxime were obtained from the literature, and susceptibility data of invasive S. pneumoniae strains recovered in 2017 (post-PCV13 vaccination period) were provided by the Public Health Regional Laboratory of Madrid. We have also studied levofloxacin because it is used to treat pneumococcal pneumonia previously to be diagnosed as bacteremic pneumonia. Monte Carlo simulation was used to estimate the probability of target attainment (PTA) and the cumulative fraction of response (CFR). All doses of benzylpenicillin except 2 mU q6h provide a high probability of treatment success for MIC values ≤ 1 mg/L; 4 mU q4h is even useful for MIC values up to 4 mg/L. This high dose, used for the treatment of meningitis, also provides high probability of treatment success for MIC ≤ 0.5 mg/L. At the susceptibility EUCAST breakpoint (≤ 0.5 mg/L), cefotaxime provides a high rate of PD target achievement, even at the lowest dose (1 g q8h). For meningitis, 2 g q6h ensures probabilities of target attainment ≥90% for MIC up to 1 mg/L. Our study confirms that after the implementation of PCV13 vaccine, the treatment with benzylpenicillin and cefotaxime provides high probability of the therapy success of IPD, including meningitis.

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).

The TLR4-MyD88 Signaling Axis Regulates Lung Monocyte Differentiation Pathways in Response to Streptococcus pneumoniae

Streptococcus pneumoniae is the main cause of bacterial pneumonia, a condition that currently produces significant global morbidity and mortality. The initial immune response to this bacterium occurs when the innate system recognizes common motifs expressed by many pathogens, events driven by pattern recognition receptors like the Toll-like family receptors (TLRs). In this study, lung myeloid-cell populations responsible for the innate immune response (IIR) against S. pneumoniae, and their dependence on the TLR4-signaling axis, were analyzed in TLR4-/- and Myeloid-Differentiation factor-88 deficient (MyD88-/-) mice. Neutrophils and monocyte-derived cells were recruited in infected mice 3-days post-infection. Compared to wild-type mice, there was an increased bacterial load in both these deficient mouse strains and an altered IIR, although TLR4-/- mice were more susceptible to bacterial infection. These mice also developed fewer alveolar macrophages, weaker neutrophil infiltration, less Ly6Chigh monocyte differentiation and a disrupted classical and non-classical monocyte profile. The pro-inflammatory cytokine profile (CXCL1, TNF-α, IL-6, and IL-1β) was also severely affected by the lack of TLR4 and no induction of Th1 was observed in these mice. The respiratory burst (ROS production) after infection was profoundly dampened in TLR4-/- and MyD88-/- mice. These data demonstrate the complex dynamics of myeloid populations and a key role of the TLR4-signaling axis in the IIR to S. pneumoniae, which involves both the MyD88 and TRIF (Toll/IL-1R domain-containing adaptor-inducing IFN-β) dependent pathways.