Follow-Up Study of Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against All-Type and Serotype-Specific Invasive Pneumococcal Disease, Denmark.

As a follow-up to a previous study, we investigated vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPSV23) against invasive pneumococcal disease (IPD) among 1,254,498 persons >65 years of age as part of a vaccination program in Denmark during April 2020-January 2023. We assessed VE by using a Cox regression model and adjusted for age, sex, and underlying conditions. Using nationwide data, we estimated a VE of PPSV23 against all-type IPD of 32% and against PPSV23-serotype IPD of 41%. Because this follow-up study had more statistical power than the original study, we also estimated VE against IPD caused by PPSV23-serotypes excluding serotype 3; serotype 3; serotype 8; serotype 22F; PPSV23 non-PCV15 serotypes; PPSV23 non-PCV20 serotypes; and IPD over time. Our findings suggest PPSV23 vaccination can protect persons >65 years of age against IPD caused by all serotypes or serotype groupings, except serotype 3.

Molecular Epidemiology of Underreported Emerging Zoonotic Pathogen Streptococcus suis in Europe.

Streptococcus suis, a zoonotic bacterial pathogen circulated through swine, can cause severe infections in humans. Because human S. suis infections are not notifiable in most countries, incidence is underestimated. We aimed to increase insight into the molecular epidemiology of human S. suis infections in Europe. To procure data, we surveyed 7 reference laboratories and performed a systematic review of the scientific literature. We identified 236 cases of human S. suis infection from those sources and an additional 87 by scanning gray literature. We performed whole-genome sequencing to type 46 zoonotic S. suis isolates and combined them with 28 publicly available genomes in a core-genome phylogeny. Clonal complex (CC) 1 isolates accounted for 87% of typed human infections; CC20, CC25, CC87, and CC94 also caused infections. Emergence of diverse zoonotic clades and notable severity of illness in humans support classifying S. suis infection as a notifiable condition.

Oral and Anal Carriage of Streptococcus pneumoniae Among Sexually Active Men With HIV Who Have Sex With Men.

People with HIV are at increased risk of pneumococcal disease. We investigate oral and anal carriage rates of Streptococcus pneumoniae by molecular methods among 82 men with HIV who have sex with men (MSM). A questionnaire, oral wash, and anal swab samples were obtained at baseline and 12 months. Oral carriage rates were 32.9% (27/82) at baseline and 41.7% (30/72) at follow-up. Anal carriage rates were 2.4% (2/82) at baseline and 2.9% (2/70) at follow-up. Genogroup 24 was predominant. Results suggest high oral carriage rates of S. pneumoniae among MSM living with HIV. A minority were anal carriers.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease among 948,263 individuals ≥ 65 years of age: a Danish cohort study.

This study aimed to estimate the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) against invasive pneumococcal disease (IPD) among individuals ≥ 65 years of age. We used Danish nationwide databases to obtain information on PPV23 vaccination, covariates, and IPD and linked data on an individual level using a unique personal identifier. A total of 948,263 individuals were included and followed between June 15, 2020, and September 18, 2021 (58.6% were vaccinated during follow-up). The adjusted vaccine effectiveness was 42% (95% confidence interval (CI): 9-63%) for all-serotype IPD and 58% (95% CI: 21-78%) for PPV23-serotype IPD, using no vaccination as the reference.

The serotype distribution of Streptococcus agalactiae (GBS) carriage isolates among pregnant women having risk factors for early-onset GBS disease: a comparative study with GBS causing invasive infections during the same period in Denmark.

BACKGROUND: We describe the serotype distribution of Streptococcus agalactiae (GBS) carriage isolates from women in labor and among GBS isolates causing invasive infections during the same period to see if the distribution of carriage serotypes reflects the GBS serotypes causing invasive diseases including early-onset disease (EOGBS). METHODS: Data on invasive isolates from 2019 including serotype, erythromycin and clindamycin susceptibility was retrieved from the Danish national reference laboratory, Statens Serum Institut. Carriage isolates were collected from women with risk factors for EOGBS enrolled at delivery at the maternity ward at a Danish University Hospital, first half of 2019. RESULTS: Among carriage isolates, the dominant serotype was IX (21 %) followed by serotype III (19 %). The resistance to erythromycin and clindamycin was 21 and 26 %, respectively. Among invasive GBS isolates, no case of EOGBS with serotype IX was detected but the distribution of serotypes were otherwise similar to the GBS carrier strains. The corresponding resistance to erythromycin and clindamycin was 23 and 15 %, respectively. Penicillin resistance was not detected among carriage nor invasive isolates. CONCLUSIONS: The distribution of serotypes among carriage and invasive GBS reflects the assumption that EOGBS occur following transmission of GBS from mother to newborn, with the exception of serotype IX.

Nasopharyngeal carriage of Streptococcus pneumoniae among healthy children in Kassena-Nankana districts of Northern Ghana.

BACKGROUND: Pneumococcal vaccine immunizations may be responsible for alterations in serotype epidemiology within a region. This study investigated the pneumococcal carriage prevalence and the impact of the 13-valent pneumococcal conjugate vaccine (PCV-13) on circulating serotypes among healthy children in Northern Ghana. METHODS: This was a cross sectional study conducted in the Kassena-Nankana districts of Northern Ghana from November to December during the dry season of 2018. Nasopharyngeal swabs collected from 193 participants were cultured per standard microbiological protocols and pneumococcal isolates were serotyped using the latex agglutination technique and the capsular Quellung reaction test. We examined for any association between the demographic characteristics of study participants and pneumococcal carriage using chi-square test and logistic regression. RESULTS: Of the 193 participants that were enrolled the mean age was 8.6 years and 54.4% were females. The carriage rate among the participants was 32.6% (63/193), and twenty different serotypes were identified. These included both vaccine serotypes (VT), 35% (7/20) and non-vaccine serotypes (NVT), 65% (13/20). The predominant serotypes (34 and 11A), both of which were NVT, accounted for a prevalence of 12.8%. PCV-13 covered only 35% of serotypes identified whiles 40% of serotypes are covered by PPV 23. CONCLUSION: Post-vaccination carriage of S. pneumoniae is high and is dominated by non-vaccine serotypes. There is therefore a need for the conduct of invasive pneumococcal disease surveillance (IPD) to find out if the high non-vaccine serotype carriage translates to disease. And in addition, a review of the currently used PCV-13 vaccine in the country would be considered relevant.

Differences in the Impact of Pneumococcal Serotype Replacement in Individuals With and Without Underlying Medical Conditions.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) have had a well-documented impact on the incidence of invasive pneumococcal disease (IPD). However, declines in IPD due to vaccine-targeted serotypes have been partially offset by increases in IPD due to nonvaccine serotypes (NVTs). The goal of this study was to quantify serotype-specific changes in the incidence of IPD that occurred in different age groups, with or without certain comorbidities, following the introduction of 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) in the childhood vaccination program in Denmark. METHODS: We used nationwide surveillance data for IPD and a hierarchical Bayesian regression framework to estimate changes in the incidence of IPD associated with the introduction of PCV7 (2007) and PCV13 (2010) while controlling for serotype-specific epidemic cycles and unrelated secular trends. RESULTS: Following the introduction of PCV7 and PCV13 in children, the net impact of serotype replacement varied considerably by age group and comorbidities. Differences in the magnitude of serotype replacement were due to variations in the incidence of NVTs in the different risk groups before the introduction of PCVs. The relative increases in the incidence of IPD caused by specific NVTs did not differ appreciably between risk groups in the postvaccination period. Serotype replacement offset a greater proportion of the benefit of PCVs in strata in which the NVTs comprised a larger proportion of cases prior to the introduction of the vaccines. CONCLUSIONS: These findings could help to predict the impact of next-generation PCVs in specific risk groups.

Effect of childhood pneumococcal conjugate vaccination on invasive disease in older adults of 10 European countries: implications for adult vaccination.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) have the potential to prevent pneumococcal disease through direct and indirect protection. This multicentre European study estimated the indirect effects of 5-year childhood PCV10 and/or PCV13 programmes on invasive pneumococcal disease (IPD) in older adults across 13 sites in 10 European countries, to support decision-making on pneumococcal vaccination policies. METHODS: For each site we calculated IPD incidence rate ratios (IRR) in people aged ≥65 years by serotype for each PCV10/13 year (2011-2015) compared with 2009 (pre-PCV10/13). We calculated pooled IRR and 95% CI using random-effects meta-analysis and PCV10/13 effect as (1 - IRR)*100. RESULTS: After five PCV10/13 years, the incidence of IPD caused by all types, PCV7 and additional PCV13 serotypes declined 9% (95% CI -4% to 19%), 77% (95% CI 67% to 84%) and 38% (95% CI 19% to 53%), respectively, while the incidence of non-PCV13 serotypes increased 63% (95% CI 39% to 91%). The incidence of serotypes included in PCV13 and not in PCV10 decreased 37% (95% CI 22% to 50%) in six PCV13 sites and increased by 50% (95% CI -8% to 146%) in the four sites using PCV10 (alone or with PCV13). In 2015, PCV13 serotypes represented 20-29% and 32-53% of IPD cases in PCV13 and PCV10 sites, respectively. CONCLUSION: Overall IPD incidence in older adults decreased moderately after five childhood PCV10/13 years in 13 European sites. Large declines in PCV10/13 serotype IPD, due to the indirect effect of childhood vaccination, were countered by increases in non-PCV13 IPD, but these declines varied according to the childhood vaccine used. Decision-making on pneumococcal vaccination for older adults must consider the indirect effects of childhood PCV programmes. Sustained monitoring of IPD epidemiology is imperative.

Pneumococcal carriage among children under five in Accra, Ghana, five years after the introduction of pneumococcal conjugate vaccine.

BACKGROUND: The study objective was to determine the carriage and serotype distribution of Streptococcus pneumoniae among children in Accra, Ghana, five years after the introduction of the pneumococcal conjugate vaccine (PCV-13) in 2012. METHODS: Nasopharyngeal swab samples were collected from 410 children below 5 years of age in Accra, Ghana, from September to December, 2016. Pneumococcal isolates were identified by optochin sensitivity and bile solubility. Serotyping was performed using the latex agglutination kit and Quellung reaction. The isolates were furthermore tested for antimicrobial susceptibility for different antimicrobials, including penicillin (PEN). Twelve isolates including seven non-typeable (NT) isolates were characterized using whole-genome sequencing analysis (WGS). RESULTS: The overall carriage prevalence was found to be 54% (95% CI, 49-59%), and 20% (95% CI, 49-59%) of the children were carrying PCV-13 included serotypes, while 37% (95% CI, 33-42%) of the children were carrying non-PCV-13 serotypes. Based on the serotype distribution, 33% of all observed serotypes were included in PCV-13 while 66% were non-PCV-13 serotypes. The dominating non-PCV-13 serotypes were 23B, 16F, and 11A followed by PCV-13 serotypes 23F and 19F. The PCV-13 covers the majority of resistant isolates in Accra. A proportion of 22.3% of the isolates showed intermediate resistance to penicillin G, while only one isolate showed full resistance. Forty-five isolates (20.5%) were defined as multidrug-resistant (MDR) as they were intermediate/resistant to three or more classes of antimicrobials. Of the seven NT isolates characterized by WGS, four showed highest match to genotype 38, while the remaining three showed highest match to genotype 14. Four MDR serotype 19A isolates were found to be MLST 320. CONCLUSION: PCV-13 introduced in Ghana did not eliminate PCV-13 covered serotypes, and the carriage rate of 54% in this study is similar to carriage studies from pre PCV-13 period. However, the penicillin non-susceptible isolates have been reduced from 45% of carriage isolates before PCV-13 introduction to 22.3% of the isolates in this study. Continuous monitoring of serotype distribution is important, and in addition, an evaluation of an alternative vaccination schedule from 3 + 0 to 2 + 1 will be important to consider.

Serologic response to pneumococcal vaccination in children experiencing recurrent invasive pneumococcal disease.

BACKGROUND: Some children are prone to recurrent invasive pneumococcal disease (rIPD) and of these, some respond insufficiently to standard pneumococcal vaccination. Little is known about how to handle these children and if they benefit from additional vaccination. Here, we present results from a nationwide study of pediatric rIPD including data on serotype-specific vaccination response to pneumococcal polysaccharide vaccination (PPV23) and pneumococcal conjugate vaccination (PCV7/13). METHODS: A retrospective, population-based study was conducted using The National Streptococcus pneumoniae Registry, which contains laboratory-confirmed data from all cases of IPD in Denmark. From January 1980-June 2013 all children aged 0-15 years with rIPD were identified. Clinical data and data on serotype-specific pneumococcal antibody response were collected. Over the years quantification of pneumococcal antibodies varied from being presented in arbitrary units (ELISA), in µg/ml (WHO ELISA) and lately in µg/ml based on Luminex technology. RESULTS: 2482 children were diagnosed with IPD and 75 episodes of rIPD were documented in 59 children. An underlying disease was documented in 45 (76%) children. Vaccination data were available for 26 children; 11 were vaccinated solely with PPV23, 8 with a combination of PPV23 + PCV7, 5 with PCV7 and 2 with PCV13. In total, nine responded to PPV23 vaccination and ten were PPV23 non-responders. Of the 15 PCV vaccinated children, two children responded subnormal to PCV7. Among PPV23 non-responders, five responded to subsequent PCV vaccination. CONCLUSIONS: In our population-based study of children with rIPD 53% of the children responded insufficiently to PPV23 vaccination. PPV23 non-responders benefitted from PCV vaccination.

Pneumococcal carriage among HIV infected children in Accra, Ghana.

BACKGROUND: Pneumococcal carriage is the precursor for development of pneumococcal disease, and is also responsible for transmission of the organism from person-to-person. In Africa, little is known about the pneumococcus in relation to people with HIV infection. The aim of the study was to investigate the epidemiology of pneumococcal carriage among HIV infected children visiting a tertiary hospital in Ghana, including the carriage prevalence, risk factors and serotype distribution. METHOD: This was a cross sectional study carried out from February to May, 2015 at the HIV Paediatric Clinic of the Korle-Bu Teaching Hospital in Accra, Ghana. One hundred and eighteen HIV infected children were recruited and nasopharyngeal (NP) swabs were collected from them. Epidemiological data on demographic, household and clinical features of the study participants were also collected. The NP specimens were cultured for Streptococcus pneumoniae and the isolates were serotyped by latex agglutination. The data of the study was analysed using STATA 11 (Strata Corp, College Station, TX, USA). RESULTS: Prevalence of pneumococcal carriage among the HIV infected children was 27.1% (95% CI: 19.1 to 35.1) and the only factor significantly associated with pneumococcal carriage was the presence of respiratory symptoms (OR, 2.63; CI, 1.06-6.53; p = 0.034). The most prevalent pneumococcal serotype among the study participants was serotype 19F (24.4%), followed by 16F (22%). Serotype coverage of the 13-valent Pneumococcal Conjugate Vaccine in this study was 41.5%. Multiple carriage of pneumococcal serotypes among the positive carriage cases was 34.3%. CONCLUSION: Pneumococcal carriage occurred in more than a quarter of the study population and was characterized by predominance of non-vaccine serotypes as well as a high prevalence of multiple carriage. Presence of respiratory symptoms appears to be a major determinant of pneumococcal carriage among the study population.

Carriage and serotype distribution of Streptococcus agalactiae in third trimester pregnancy in southern Ghana.

BACKGROUND: The aim of this study was to determine the prevalence of Streptococcus agalactiae (group B streptococci, GBS) among healthy, pregnant women attending antenatal care at different study sites in the Greater Accra Region, Ghana. METHODS: Between 2010 and June 2013, recto-vaginal swab samples were collected from pregnant women attending antenatal care from two study sites in southern Ghana. The samples were collected within 35 and 37 weeks of the gestation period. These were inoculated into Todd-Hewitt broth followed by sub-culturing onto a sheep-blood agar plate. Identification was performed on a single subcultured colony. Gram staining was performed, and isolates were evaluated for beta-haemolytic reactions. Furthermore, the isolates were serotyped using the GBS latex serotyping kit. RESULTS: The carriage rates were found to be 25.5% (95% CI: 19.6-32.1) to 28.0% (95% CI: 21.9-34.8) for the two collection sites. The most common serotypes were serotypes VII and IX. The data showed that women below 20 years of age or above 30 years of age have a significantly (p = 0.037) higher risk of carrying GBS compared to women from the age group of 20 to 30 years. CONCLUSIONS: The findings of this study revealed that prevalence of GBS colonization in pregnant women in Greater Accra region is high and comparable to rates observed in South Africa and Western countries. The most prevalent serotypes were serotypes VII and IX, which have not been observed before in West Africa.

Impact of 13-valent pneumococcal conjugate vaccination in invasive pneumococcal disease incidence and mortality.

BACKGROUND: The impact of the 13-valent pneumococcal conjugate vaccine (PCV13) at the population level is unclear. We explored PCV13's effect in reducing invasive pneumococcal disease (IPD)-related morbidity and mortality, and whether serotype-specific changes were attributable to vaccination or expected as a part of natural, cyclical variations. METHODS: This was a Danish nationwide population-based cohort study based on the linkage of laboratory surveillance data and the Danish Civil Registration System. Changes in IPD incidence and mortality during baseline (2000-2007), 7-valent pneumococcal conjugate vaccine (PCV7) (2008-2010), and PCV13 (2011-2013) periods were estimated. Predicted incidences of serotypes were estimated controlling for cyclical trends from historical patterns observed during the past 20 years. RESULTS: We observed a 21% reduction (95% confidence interval [CI], 17%-25%) in IPD incidence in the total population after PCV13's introduction, and a 71% reduction (95% CI, 62%-79%) in children aged <2 years, considered as the vaccine effectiveness. We estimated a 28% reduction (95% CI, 18%-37%) in IPD-related 30-day mortality, from 3.4 deaths (95% CI, 3.2-3.6) per 100 000 population in the pre-PCV period to 2.4 (95% CI, 2.2-2.7) in the PCV13 period. The decline in mortality was observed across all age groups but was mainly related to mortality reductions in the nonvaccinated population. For serotypes 1 and 3, there were no significant changes in incidence beyond what would be expected from natural cyclical patterns. Serotype 19A significantly increased following PCV7's introduction, but the incidence declined toward baseline in 2012. CONCLUSIONS: PCV13 has brought greater benefits than we had expected in our setting. We observed a further decline on IPD incidence shortly after the shift from PCV7 to PCV13 in the national immunization program. This decline was accompanied by a substantial population-level decline in pneumococcal-related mortality of nearly 30% among nonvaccinated persons.

Identification of antibiotic induced persister cells in Streptococcus agalactiae.

Antibiotic persistence is a phenomenon, where a small fraction of a bacterial population expresses a phenotypic variation that allows them to survive antibiotic treatment, which is lethal to the rest of the population. These cells are called persisters cells, and their occurrence has been associated with recurrent disease. Streptococcus agalactiae is a human pathobiont, able to cause invasive infections, and recurrent infections have been reported to occur in both newborns and adults. In this study, we demonstrated that S. agalactiae NEM316 can form persister cells when exposed to antibiotics from different classes. The frequency of persister cell formation was dependent on bacterial growth phase and the class of antibiotics. The ability to form persister cells in response to penicillin was shown to be a general trait among different clinical S. agalactiae isolates, independent of sero- and sequence-type. Taken together, this study shows the existence of antibiotic tolerant S. agalactiae persister cells, which may explain why this bacterial species frequently persists after treatment of invasive infection and can be associated with recurrent disease.

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.

International circumpolar surveillance: update on the interlaboratory quality control program for Streptococcus pneumoniae, 2009 to 2020.

The International Circumpolar Surveillance (ICS) program is a population-based surveillance network for invasive bacterial diseases throughout Arctic countries and territories. The ICS quality control program for Streptococcus pneumoniae serotyping and antimicrobial susceptibility testing has been ongoing since 1999. Current participating laboratories include the Provincial Laboratory for Public Health in Edmonton, Alberta; Laboratoire de santé publique du Québec in Sainte-Anne-de-Bellevue, Québec; the Centers for Disease Control's Arctic Investigations Program in Anchorage, Alaska; the Neisseria and Streptococcus Reference Laboratory at Statens Serum Institut in Copenhagen, Denmark; the Department of Clinical Microbiology, Landspitali in Reykjavik, Iceland; and Public Health Agency of Canada's National Microbiology Laboratory in Winnipeg, Manitoba. From 2009 to 2020, 140 isolates of S. pneumoniae were distributed among the six laboratories as part of the quality control program. Overall serotype concordance was 96.9%, with 99.3% concordance to pool level. All participating laboratories had individual concordance rates >92% for serotype and >97% for pool. Overall concordance by modal minimum inhibitory concentration (MIC) for testing done by broth microdilution or Etest was 99.1%, and >98% for all antimicrobials tested. Categorical concordance was >98% by both CLSI and EUCAST criteria. For two laboratories performing disc diffusion, rates of concordance by modal MIC were >97% for most antimicrobials, except chloramphenicol (>93%) and trimethoprim/sulfamethoxazole (>88%). Data collected from 12 years of the ICS quality control program for S. pneumoniae demonstrate excellent (≥95%) overall concordance for serotype and antimicrobial susceptibility testing results across six laboratories. IMPORTANCE: Arctic populations experience several social and physical challenges that lead to the increased spread and incidence of invasive diseases. The International Circumpolar Surveillance (ICS) program was developed to monitor five invasive bacterial diseases in Arctic countries and territories. Each ICS organism has a corresponding interlaboratory quality control (QC) program for laboratory-based typing, to ensure the technical precision and accuracy of reference testing services for these regions, and identify and correct potential problems. Here, we describe the results of the ICS Streptococcus pneumoniae QC program, from 2009 to 2020. Excellent overall concordance was achieved for serotype and antimicrobial susceptibility testing results across six laboratories. Ongoing participation in these QC programs ensures the continuation of quality surveillance systems within Arctic populations that experience health disparities.

Penicillin resistance and serotype distribution of Streptococcus pneumoniae in Ghanaian children less than six years of age.

BACKGROUND: The objective of this study was to determine the prevalence of nasopharyngeal carriage, serotype distribution, and penicillin resistance of Streptococcus pneumoniae in children ≤ 6 years of age in Ghana. METHODS: A cross-sectional study was carried out on a cluster-randomized sample of children ≤ 6 years of age attending nurseries and kindergartens in Accra and Tamale, Ghana. Basic data on age, sex and exposure to antimicrobials in the previous month were collected on all study subjects. Nasopharyngeal swabs were obtained from participants and all pneumococcal isolates were characterized by serotyping and their penicillin resistance determined. RESULTS: The overall prevalence of pneumococcal carriage among the children was 34% in Accra and 31% in Tamale. The predominant serotypes were 19F, 6B, 23F, and 6A with 23% of the isolates being non-typable in Accra and 12% in Tamale. Only two isolates (serotypes 19F and 6B) from Tamale had a MIC >2 µg/ml and were classified as fully penicillin resistant with 45% of the isolates having intermediate resistance. CONCLUSIONS: These findings indicate that the 13-valent pneumococcal conjugate vaccine (PCV-13) recently introduced in Ghana will cover 48% and 51% of the serotypes identified in Accra and Tamale, respectively. The 23-valent pneumococcal polysaccharide vaccine (PPV-23) will cover 54% of all serotypes detected. The two penicillin resistant isolates (MIC 32 µg/ml) were serotypes included in both PCV-13 and PPV-23. A nationwide monitoring system of penicillin susceptibility patterns and pneumococcal serotypes is recommended.

Impact of positive chest X-ray findings and blood cultures on adverse outcomes following hospitalized pneumococcal lower respiratory tract infection: a population-based cohort study.

BACKGROUND: Little is known about the clinical presentation and outcome of pneumococcal lower respiratory tract infection (LRTI) without positive chest X-ray findings and blood cultures. We investigated the prognostic impact of a pulmonary infiltrate and bacteraemia on the clinical course of hospitalized patients with confirmed pneumococcal LRTI. METHODS: We studied a population-based multi-centre cohort of 705 adults hospitalized with LRTI and Streptococcus pneumoniae in LRT specimens or blood: 193 without pulmonary infiltrate or bacteraemia, 250 with X-ray confirmed pneumonia, and 262 with bacteraemia. We compared adverse outcomes in the three groups and used multiple regression analyses to adjust for differences in age, sex, comorbidity, and lifestyle factors. RESULTS: Patients with no infiltrate and no bacteraemia were of similar age but had more comorbidity than the other groups (Charlson index score ≥1: no infiltrate and no bacteraemia 81% vs. infiltrate without bacteraemia 72% vs. bacteraemia 61%), smoked more tobacco, and had more respiratory symptoms. In contrast, patients with a pulmonary infiltrate or bacteraemia had more inflammation (median C-reactive protein: no infiltrate and no bacteraemia 82 mg/L vs. infiltrate without bacteraemia 163 mg/L vs. bacteraemia 316 mg/L) and higher acute disease severity scores. All adverse outcomes increased from patients with no infiltrate and no bacteraemia to those with an infiltrate and to those with bacteraemia: Length of hospital stay (5 vs. 6 vs. 8 days); intensive care admission (7% vs. 20% vs. 23%); pulmonary complications (1% vs. 5% vs. 14%); and 30-day mortality (5% vs. 11% vs. 21%). Compared with patients with no infiltrate and no bacteraemia, the adjusted 30-day mortality rate ratio was 1.9 (95% confidence interval (CI) 0.9-4.1) in patients with an infiltrate without bacteraemia and 4.1 (95% CI 2.0-8.5) in bacteraemia patients. Adjustment for acute disease severity and inflammatory markers weakened these associations. CONCLUSIONS: Hospitalization with confirmed pneumococcal LRTI is associated with substantial morbidity and mortality even without positive chest X-ray findings and blood cultures. Still, there is a clinically important outcome gradient from LRTI patients with pneumococcal isolation only to those with detected pulmonary infiltrate or bacteraemia which is partly mediated by higher acute disease severity and inflammation.

Decreased Pneumococcal Carriage Among Older Adults in Denmark During the COVID-19 Lockdown.

Background: COVID-19 containment measures reduced the burden of invasive pneumococcal disease. Data on pneumococcal carriage rates among adults during the pandemic are scarce. Methods: Naso- and oropharyngeal swabs and questionnaires were collected during January 2019 to December 2021 from adults ≥64 years of age. Carriage was determined by lytA/piaB PCR. Results: A total of 1556 participants provided paired naso- and oropharyngeal swabs. Their median age was 74 years (IQR, 70-79). Streptococcus pneumoniae DNA was detected in 146 (9.4%) oropharyngeal swabs and 34 (2.2%) nasopharyngeal. The carriage rate decreased from 12.9% (95% CI, 10.1%-16.1%, n = 66/511) prelockdown (January 2019-February 2020) to 4.2% (95% CI, 2.0%-7.5%, n = 10/240) during lockdown (March 2020-February 2021) and increased to 12.1% (95% CI, 9.8%-14.7%, n = 87/719) with the reopening of society (March 2021-December 2021; P = .0009). Conclusions: Pneumococcal carriage prevalence declined significantly during pandemic mitigation measures and rebounded to prepandemic levels as measures were lifted.

Predictors of serological non-response to the 13-valent pneumococcal conjugate vaccine followed by the 23-valent polysaccharide vaccine among adults living with HIV.

BACKGROUND: People living with HIV (PLWH) have higher incidence of pneumococcal disease compared to people without HIV. Immunization with pneumococcal vaccines is recommended, but serological non-response to pneumococcal vaccination is common for largely unknown reasons. METHODS: PLWH on antiretroviral treatment and no prior pneumococcal vaccination received the 13-valent pneumococcal conjugate vaccine (PCV13) followed 60 days later by the 23-valent polysaccharide vaccine (PPV23). Serological response was evaluated 30 days post-PPV23 by antibodies against 12 serotypes covered by both PCV13 and PPV23. Seroprotection was defined as a ≥2-fold rise to a level above 1.3 µg/ml in geometric mean concentration (GMC) across all serotypes. Associations with non-responsiveness were evaluated by logistic regression. RESULTS: Fifty-two virologically suppressed PLWH (median age of 50 years (IQR 44-55) and median CD4 count of 634 cells/mm3 (IQR 507-792)) were included. Forty-six percent (95 % CI 32-61, n = 24) achieved seroprotection. Serotypes 14, 18C and 19F had the highest, and serotypes 3, 4 and 6B the lowest GMCs. Pre-vaccination GMC levels less than 100 ng/ml were associated with increased odds of non-responsiveness compared to levels above 100 ng/ml (adjusted OR 8.7, 95 % CI 1.2-63.6, p = 0.0438). CONCLUSION: Less than half of our study population achieved anti-pneumococcal seroprotective levels following PCV13 and PPV23 immunization. Low pre-vaccination GMC levels were associated with non-response. Further research is required to optimize vaccination strategies that achieve higher seroprotection in this high-risk group.