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Article ; Online: Clonal Expansion of a Streptococcus pneumoniae Serotype 3 Capsule Variant Sequence Type 700 With Enhanced Vaccine Escape Potential After 13-Valent Pneumococcal Conjugate Vaccine Introduction.

Kalizang'oma, Akuzike / Swarthout, Todd D / Mwalukomo, Thandie S / Kamng'ona, Arox / Brown, Comfort / Msefula, Jacquline / Demetriou, Hayley / Chan, Jia Mun / Roalfe, Lucy / Obolski, Uri / Lourenço, Jose / Goldblatt, David / Chaguza, Chrispin / French, Neil / Heyderman, Robert S

The Journal of infectious diseases

2024

Abstract: Background: Streptococcus pneumoniae serotype 3 remains a problem globally. Malawi introduced 13-valent pneumococcal conjugate vaccine (PCV13) in 2011, but there has been no direct protection against serotype 3 carriage. We explored whether vaccine ... ...

Abstract	Background: Streptococcus pneumoniae serotype 3 remains a problem globally. Malawi introduced 13-valent pneumococcal conjugate vaccine (PCV13) in 2011, but there has been no direct protection against serotype 3 carriage. We explored whether vaccine escape by serotype 3 is due to clonal expansion of a lineage with a competitive advantage. Methods: The distribution of serotype 3 Global Pneumococcal Sequence Clusters (GPSCs) and sequence types (STs) globally was assessed using sequences from the Global Pneumococcal Sequencing Project. Whole-genome sequences of 135 serotype 3 carriage isolates from Blantyre, Malawi (2015-2019) were analyzed. Comparative analysis of the capsule locus, entire genomes, antimicrobial resistance, and phylogenetic reconstructions were undertaken. Opsonophagocytosis was evaluated using serum samples from vaccinated adults and children. Results: Serotype 3 GPSC10-ST700 isolates were most prominent in Malawi. Compared with the prototypical serotype 3 capsular polysaccharide locus sequence, 6 genes are absent, with retention of capsule polysaccharide biosynthesis. This lineage is characterized by increased antimicrobial resistance and lower susceptibility to opsonophagocytic killing. Conclusions: A serotype 3 variant in Malawi has genotypic and phenotypic characteristics that could enhance vaccine escape and clonal expansion after post-PCV13 introduction. Genomic surveillance among high-burden populations is essential to improve the effectiveness of next-generation pneumococcal vaccines.
Language	English
Publishing date	2024-03-26
Publishing country	United States
Document type	Journal Article
ZDB-ID	3019-3
ISSN	1537-6613 ; 0022-1899
ISSN (online)	1537-6613
ISSN	0022-1899
DOI	10.1093/infdis/jiae040
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Article ; Online: Invasiveness potential of pneumococcal serotypes in children after introduction of PCV13 in Blantyre, Malawi.

Kirolos, Amir / Swarthout, Todd D / Mataya, Andrew A / Bonomali, Farouck / Brown, Comfort / Msefula, Jacquline / Bar-Zeev, Naor / Iroh Tam, Pui-Ying / Alaerts, Maaike / Bilima, Sithembile / Heyderman, Robert S / French, Neil

BMC infectious diseases

2023 Volume 23, Issue 1, Page(s) 56

Abstract: Introduction: The introduction of PCV13 to the Malawi infant immunization schedule in 2011 has been associated with reduced disease from Streptococcus pneumoniae. Improved understanding of serotypes with high invasive potential can guide future ... ...

Abstract	Introduction: The introduction of PCV13 to the Malawi infant immunization schedule in 2011 has been associated with reduced disease from Streptococcus pneumoniae. Improved understanding of serotypes with high invasive potential can guide future vaccination interventions. We aimed to estimate pneumococcal serotypes associated with acute respiratory infection (ARI) and invasive pneumococcal disease (IPD) in hospitalized children in Blantyre, Malawi. Methods: We analysed data from healthy children under 5 years in the community in Blantyre and children admitted to Queen Elizabeth Central Hospital with ARI between 2015 and 2018. Nasopharyngeal swabs from children were tested for S. pneumoniae and serotyped by latex agglutination if positive. We analysed culture-positive blood and cerebrospinal fluid samples from admitted children between 2012 and 2018 to identify cases of IPD after the introduction of PCV13. We calculated the age-adjusted odds ratio (OR) of carriage for S. pneumoniae vaccine serotypes (VT) comparing those with ARI to healthy children. We also calculated age-adjusted ORs comparing serotypes causing IPD to carriage in the community with OR > 1 indicating high invasive potential. Results: Serotypes 5 (OR 24.73 [95% CI 7.90-78.56] p < 0.001), 1 (OR 23.38 [95% CI 9.75-56.06] p < 0.001), and 6B (OR 4.73 [95% CI 1.66-11.64] p = 0.001) had high invasive potential. Serotype 6B was no longer significant (OR 1.34 [95% CI 0.07-6.87] p = 0.777) in a sensitivity analysis accounting for year of recruitment. The prevalence of S. pneumoniae carriage in the community was 72.6% [95% CI 71.3-74.0] (3078/4238) and 23.4% (719/3078) of positive community samples were VT. The carriage prevalence in those hospitalised with ARI was 45.5% [95% CI 42.1-48.9] (389/855) and 43.8% of hospital attendees reported antibiotic use prior to admission. We did not identify significant associations with carriage of any serotypes in those with ARI. Conclusions: Pneumococcal serotypes 5 and 1 are associated with high invasive potential. Despite high community pneumococcal carriage, pre-hospital antibiotic usage likely reduces pneumococcal detection among children admitted in this setting and further research is needed to investigate serotypes associated with ARI. Data from this study can guide future preventative vaccination strategies in Malawi.
MeSH term(s)	Infant ; Child ; Humans ; Child, Preschool ; Serogroup ; Malawi/epidemiology ; Carrier State/epidemiology ; Nasopharynx ; Streptococcus pneumoniae ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Pneumococcal Vaccines ; Respiratory Tract Infections ; Anti-Bacterial Agents
Chemical Substances	Pneumococcal Vaccines ; Anti-Bacterial Agents
Language	English
Publishing date	2023-01-26
Publishing country	England
Document type	Journal Article
ZDB-ID	2041550-3
ISSN	1471-2334 ; 1471-2334
ISSN (online)	1471-2334
ISSN	1471-2334
DOI	10.1186/s12879-023-08022-4
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Article ; Online: Cross-sectional health centre and community-based evaluation of the impact of pneumococcal and malaria vaccination on antibiotic prescription and usage, febrile illness and antimicrobial resistance in young children in Malawi: the IVAR study protocol.

Singleton, David / Ibarz-Pavon, Ana / Swarthout, Todd D / Bonomali, Farouck / Cornick, Jennifer / Kalizang'oma, Akuzike / Ntiza, Noah / Brown, Comfort / Chipatala, Raphael / Nyangulu, Wongani / Chirombo, James / Kawalazira, Gift / Chibowa, Henry / Mwansambo, Charles / Maleta, Kenneth Mphatso / French, Neil / Heyderman, Robert S

BMJ open

2023 Volume 13, Issue 5, Page(s) e069560

Abstract: Introduction: Vaccination is a potentially critical component of efforts to arrest development and dissemination of antimicrobial resistance (AMR), though little is known about vaccination impact within low-income and middle-income countries. This study ...

Abstract	Introduction: Vaccination is a potentially critical component of efforts to arrest development and dissemination of antimicrobial resistance (AMR), though little is known about vaccination impact within low-income and middle-income countries. This study will evaluate the impact of vaccination on reducing carriage prevalence of resistant Methods and analysis: Six cross-sectional surveys will be implemented within primary healthcare centres (n=3000 users of outpatient facilities per survey) and their local communities (n=700 healthy children per survey): three surveys in Blantyre district (PCV13 component) and three surveys in Mangochi district (RTS,S/AS01 component). We will evaluate antibiotic prescription practices and AMR carriage in children ≤3 years. For the PCV13 component, surveys will be conducted 9, 18 and 33 months following a 3+0 to 2+1 schedule change. For the RTS,S/AS01 component, surveys will be conducted 32, 44 and 56 months post-RTS,S/AS01 introduction. Six health centres in each study component will be randomly selected for study inclusion. Between intervention arms, the primary outcome will be the difference in penicillin non-susceptibility prevalence among Ethics and dissemination: This study has been approved by the Kamuzu University of Health Sciences (Ref: P01-21-3249), University College London (Ref: 18331/002) and University of Liverpool (Ref: 9908) Research Ethics Committees. Parental/caregiver verbal or written informed consent will be obtained prior to inclusion or recruitment in the health centre-based and community-based activities, respectively. Results will be disseminated via the Malawi Ministry of Health, WHO, peer-reviewed publications and conference presentations.
MeSH term(s)	Humans ; Child ; Infant ; Child, Preschool ; Streptococcus pneumoniae ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Anti-Bacterial Agents/pharmacology ; Anti-Bacterial Agents/therapeutic use ; Cross-Sectional Studies ; Malaria Vaccines ; Malawi/epidemiology ; Drug Resistance, Bacterial ; Pneumococcal Vaccines ; Vaccination ; Penicillins ; Nasopharynx ; Malaria/epidemiology ; Malaria/prevention & control ; Carrier State/epidemiology
Chemical Substances	Anti-Bacterial Agents ; Malaria Vaccines ; Pneumococcal Vaccines ; Penicillins
Language	English
Publishing date	2023-05-12
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2599832-8
ISSN	2044-6055 ; 2044-6055
ISSN (online)	2044-6055
ISSN	2044-6055
DOI	10.1136/bmjopen-2022-069560
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Article ; Online: Changing Incidence of Invasive Pneumococcal Disease in Infants Less Than 90 Days of Age Before and After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine in Blantyre, Malawi: A 14-Year Hospital Based Surveillance Study.

Koenraads, Marianne / Swarthout, Todd D / Bar-Zeev, Naor / Brown, Comfort / Msefula, Jacquline / Denis, Brigitte / Dube, Queen / Gordon, Stephen B / Heyderman, Robert S / Gladstone, Melissa J / French, Neil

The Pediatric infectious disease journal

2022 Volume 41, Issue 9, Page(s) 764–768

Abstract: Background: Invasive pneumococcal disease (IPD) in young infants is uncommon but associated with high morbidity and mortality. Accurate data on the burden of IPD in young infants in low-income countries are lacking. We examined the burden of IPD in ... ...

Abstract	Background: Invasive pneumococcal disease (IPD) in young infants is uncommon but associated with high morbidity and mortality. Accurate data on the burden of IPD in young infants in low-income countries are lacking. We examined the burden of IPD in infants <90 days old in Blantyre, Malawi over a 14-year period and evaluated the indirect impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on vaccine-serotype IPD (VT-IPD) in this population. Methods: We conducted laboratory-based prospective IPD surveillance in infants <90 days of age admitted to Queen Elizabeth Central Hospital in Blantyre between 2005 and 2018, including 7 years pre-PCV13 and 7 years post-PCV13 introduction. IPD was defined as Streptococcus pneumoniae identified by culture from blood or cerebrospinal fluid. Serotypes were determined by multiplex polymerase chain reaction and latex agglutination testing. Results: We identified 130 cases of culture-confirmed IPD in infants <90 days old between 2005 and 2018. Total IPD incidence was declining before PCV13 introduction. The mean incidence of IPD was significantly lower in the post-PCV13 era. Serotypes 5 (27.8%) and 1 (15.6%) were most prevalent. Even after PCV13 introduction, VTs remained the primary cause of IPD, with serotype 5 accounting for 17.4% and serotype 1 for 13.0% of cases in young infants. Conclusion: Vaccine serotypes 1 and 5 were the main cause of IPD in neonates and young infants, both before and after PCV13 introduction. This suggests incomplete indirect protection with persisting VT carriage across the population despite vaccination in this setting. Alternative vaccine schedules and other vaccine introduction approaches need to be considered to protect this vulnerable population.
MeSH term(s)	Hospitals ; Humans ; Incidence ; Infant ; Infant, Newborn ; Malawi/epidemiology ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Pneumococcal Vaccines ; Prospective Studies ; Serogroup ; Vaccines, Conjugate
Chemical Substances	Pneumococcal Vaccines ; Vaccines, Conjugate
Language	English
Publishing date	2022-06-13
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	392481-6
ISSN	1532-0987 ; 0891-3668
ISSN (online)	1532-0987
ISSN	0891-3668
DOI	10.1097/INF.0000000000003606
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Article ; Online: Risk factors for pneumococcal carriage in adults living with HIV on antiretroviral therapy in the infant pneumococcal vaccine era in Malawi.

Thindwa, Deus / Mwalukomo, Thandie S / Msefula, Jacquline / Jambo, Kondwani C / Brown, Comfort / Kamng'ona, Arox / Mwansambo, Charles / Ojal, John / Flasche, Stefan / French, Neil / Heyderman, Robert S / Swarthout, Todd D

AIDS (London, England)

2022 Volume 36, Issue 14, Page(s) 2045–2055

Abstract: Objective: Adults living with HIV (ALWHIV) on antiretroviral therapy (ART) are at high risk of pneumococcal carriage and disease. To help evaluate carriage risk in African ALWHIV at least 4 years after infant pneumococcal conjugate vaccination ... ...

Abstract	Objective: Adults living with HIV (ALWHIV) on antiretroviral therapy (ART) are at high risk of pneumococcal carriage and disease. To help evaluate carriage risk in African ALWHIV at least 4 years after infant pneumococcal conjugate vaccination introduction in 2011, we assessed association between pneumococcal carriage and potential risk factors. Methods: Nasopharyngeal swabs were collected from adults aged 18-40 years attending an ART clinic during rolling, cross-sectional surveys in Blantyre, Malawi between 2015 and 2019. We fitted generalized additive models to estimate the risk of sex, social economic status (SES), living with a child less than 5 years, and ART duration on carriage. Results: Of 2067 adults, median age was 33 years (range 28-37), 1427 (69.0%) were women, 1087 (61.4%) were in low-middle socioeconomic-status (SES), 910 (44.0%) were living with a child less than 5 years, and median ART duration was 3 years (range 0.004-17). We estimated 38.2 and 60.6% reductions in overall and vaccine-serotype carriage prevalence. Overall carriage was associated with low SES, living with a child less than 5 years and shorter duration on ART. By contrast, vaccine-type carriage was associated with living without a child less than 5 years and male sex. Conclusion: Despite temporal reductions in overall and vaccine-serotype carriage, there is evidence of incomplete vaccine-serotype indirect protection. A targeted-vaccination campaign should be considered for ALWHIV, along with other public health measures to further reduce vaccine-serotype carriage and therefore disease.
MeSH term(s)	Adult ; Female ; Humans ; Infant ; Male ; Carrier State/epidemiology ; Cross-Sectional Studies ; HIV Infections/complications ; HIV Infections/drug therapy ; Malawi/epidemiology ; Nasopharynx ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Pneumococcal Vaccines ; Prevalence ; Risk Factors ; Streptococcus pneumoniae ; Infant, Newborn ; Child, Preschool
Chemical Substances	Pneumococcal Vaccines
Language	English
Publishing date	2022-08-19
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	639076-6
ISSN	1473-5571 ; 0269-9370 ; 1350-2840
ISSN (online)	1473-5571
ISSN	0269-9370 ; 1350-2840
DOI	10.1097/QAD.0000000000003365
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Article ; Online: Waning of antibody levels induced by a 13-valent pneumococcal conjugate vaccine, using a 3 + 0 schedule, within the first year of life among children younger than 5 years in Blantyre, Malawi: an observational, population-level, serosurveillance study.

Swarthout, Todd D / Henrion, Marc Y R / Thindwa, Deus / Meiring, James E / Mbewe, Maurice / Kalizang'Oma, Akuzike / Brown, Comfort / Msefula, Jacquline / Moyo, Brewster / Mataya, Andrew A / Barnaba, Susanne / Pearce, Emma / Gordon, Melita / Goldblatt, David / French, Neil / Heyderman, Robert S

The Lancet. Infectious diseases

2022 Volume 22, Issue 12, Page(s) 1737–1747

Abstract: Background: Pneumococcal conjugate vaccines (PCVs) induce serotype-specific IgG antibodies, effectively reducing vaccine-serotype carriage and invasive pneumococcal disease (IPD). IgG production wanes approximately 1 month after vaccination in absence ... ...

Abstract	Background: Pneumococcal conjugate vaccines (PCVs) induce serotype-specific IgG antibodies, effectively reducing vaccine-serotype carriage and invasive pneumococcal disease (IPD). IgG production wanes approximately 1 month after vaccination in absence of serotype-specific exposure. With uncertainty surrrounding correlate of protection (CoP) estimates and with persistent vaccine-serotype carriage and vaccine-serotype IPD after PCV13 introduction, we aimed to profile population-level immunogenicity among children younger than 5 years in Blantyre, Malawi. Methods: For this serosurveillance study, we used a random subset of samples from a prospective population-based serosurvey in Blantyre, Malawi, done between Dec 16, 2016, and June 27, 2018. Sample selection was based on age category optimisation among children younger than 5 years, adequate sample volume, and available budget. We measured serotype-specific IgGs against the 13 vaccine serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) and two non-vaccine serotypes (12F and 33F), as well as IgGs against three pneumococcal proteins (PsaA, NanA, and Ply), using ELISA and a direct-binding electrochemiluminescence-based multiplex assay. We estimated population-level, serotype-specific immunogenicity profiles using a linear spline regression model. Analyses included samples stratified to 20 3-month age strata (eg, age <3 months to 57-59 months). Findings: We evaluated 638 plasma samples: 556 primary samples and 82 unique secondary samples (each linked to one primary sample). Immunogenicity profiles revealed a consistent pattern among vaccine serotypes except serotype 3: a vaccine-induced IgG peak followed by waning to a nadir and subsequent increase in titre. For serotype 3, we observed no apparent vaccine-induced increase. Heterogeneity in parameters included age range at post-vaccination nadir (from 11·2 months [19A] to 27·3 months [7F]). The age at peak IgG titre ranged from 2·69 months (5) to 6·64 months (14). Titres dropped below CoPs against IPD among nine vaccine serotypes (1, 3, 4, 5, 6B, 7F, 9V, 18C, and 23F) and below CoPs against carriage for ten vaccine serotypes (1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F). Increasing antibody concentrations among older children and seroincident events were consistent with ongoing vaccine-serotype exposure. Interpretation: A 3 + 0 PCV13 schedule with high uptake has not led to sustained population-level antibody immunity beyond the first year of life. Indeed, post-vaccine antibody concentrations dropped below putative CoPs for several vaccine serotypes, potentially contributing to persistent vaccine-serotype carriage and residual vaccine-serotype IPD in Malawi and other similar settings. Policy decisions should consider alternative vaccine strategies, including a booster dose, to achieve sustained vaccine-induced antibody titres, and thus control. Funding: Bill & Melinda Gates Foundation, Wellcome UK, and National Institute for Health and Care Research.
MeSH term(s)	Child ; Humans ; Infant ; Adolescent ; Child, Preschool ; Vaccines, Conjugate ; Malawi/epidemiology ; Prospective Studies ; Antibodies, Bacterial ; Pneumococcal Vaccines ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Immunoglobulin G
Chemical Substances	Vaccines, Conjugate ; Antibodies, Bacterial ; Pneumococcal Vaccines ; Immunoglobulin G
Language	English
Publishing date	2022-08-24
Publishing country	United States
Document type	Observational Study ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2061641-7
ISSN	1474-4457 ; 1473-3099
ISSN (online)	1474-4457
ISSN	1473-3099
DOI	10.1016/S1473-3099(22)00438-8
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Article ; Online: First case report of a successfully managed severe COVID-19 infection in Malawi.

Banda, Ndaziona Peter / Hara, Wilned / Cocker, Derek / Musasa, Samantha / Burke, Rachael Mary / Brown, Comfort / Nyasulu, Vita / Mandalo, Jonathon / Tembo, Dumizulu / Kachingwe, Mtisunge / Cornick, Jenifer / Jambo, Kondwani / Morton, Ben

Malawi medical journal : the journal of Medical Association of Malawi

2021 Volume 32, Issue 4, Page(s) 226–228

MeSH term(s)	Administration, Intravenous ; Anti-Bacterial Agents/therapeutic use ; Anticoagulants/administration & dosage ; Anticoagulants/therapeutic use ; COVID-19/diagnosis ; COVID-19/therapy ; COVID-19 Nucleic Acid Testing ; Ceftriaxone/administration & dosage ; Ceftriaxone/therapeutic use ; Dexamethasone/administration & dosage ; Dexamethasone/therapeutic use ; Enoxaparin/administration & dosage ; Enoxaparin/therapeutic use ; Heparin, Low-Molecular-Weight/administration & dosage ; Heparin, Low-Molecular-Weight/therapeutic use ; Humans ; Male ; Middle Aged ; Reverse Transcriptase Polymerase Chain Reaction ; SARS-CoV-2/genetics ; SARS-CoV-2/isolation & purification ; Treatment Outcome
Chemical Substances	Anti-Bacterial Agents ; Anticoagulants ; Enoxaparin ; Heparin, Low-Molecular-Weight ; Ceftriaxone (75J73V1629) ; Dexamethasone (7S5I7G3JQL)
Language	English
Publishing date	2021-06-24
Publishing country	Malawi
Document type	Case Reports
ZDB-ID	2491952-4
ISSN	1995-7270 ; 1995-7270
ISSN (online)	1995-7270
ISSN	1995-7270
DOI	10.4314/mmj.v32i4.8
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Article ; Online: The metabolic, virulence and antimicrobial resistance profiles of colonising Streptococcus pneumoniae shift after PCV13 introduction in urban Malawi.

Obolski, Uri / Swarthout, Todd D / Kalizang'oma, Akuzike / Mwalukomo, Thandie S / Chan, Jia Mun / Weight, Caroline M / Brown, Comfort / Cave, Rory / Cornick, Jen / Kamng'ona, Arox Wadson / Msefula, Jacquline / Ercoli, Giuseppe / Brown, Jeremy S / Lourenço, José / Maiden, Martin C / French, Neil / Gupta, Sunetra / Heyderman, Robert S

Nature communications

2023 Volume 14, Issue 1, Page(s) 7477

Abstract: Streptococcus pneumoniae causes substantial mortality among children under 5-years-old worldwide. Polysaccharide conjugate vaccines (PCVs) are highly effective at reducing vaccine serotype disease, but emergence of non-vaccine serotypes and persistent ... ...

Abstract	Streptococcus pneumoniae causes substantial mortality among children under 5-years-old worldwide. Polysaccharide conjugate vaccines (PCVs) are highly effective at reducing vaccine serotype disease, but emergence of non-vaccine serotypes and persistent nasopharyngeal carriage threaten this success. We investigated the hypothesis that following vaccine, adapted pneumococcal genotypes emerge with the potential for vaccine escape. We genome sequenced 2804 penumococcal isolates, collected 4-8 years after introduction of PCV13 in Blantyre, Malawi. We developed a pipeline to cluster the pneumococcal population based on metabolic core genes into "Metabolic genotypes" (MTs). We show that S. pneumoniae population genetics are characterised by emergence of MTs with distinct virulence and antimicrobial resistance (AMR) profiles. Preliminary in vitro and murine experiments revealed that representative isolates from emerging MTs differed in growth, haemolytic, epithelial infection, and murine colonisation characteristics. Our results suggest that in the context of PCV13 introduction, pneumococcal population dynamics had shifted, a phenomenon that could further undermine vaccine control and promote spread of AMR.
MeSH term(s)	Child ; Humans ; Animals ; Mice ; Infant ; Child, Preschool ; Streptococcus pneumoniae/genetics ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Anti-Bacterial Agents/pharmacology ; Anti-Bacterial Agents/therapeutic use ; Malawi/epidemiology ; Virulence/genetics ; Drug Resistance, Bacterial/genetics ; Pneumococcal Vaccines ; Serogroup ; Nasopharynx ; Carrier State/epidemiology
Chemical Substances	Anti-Bacterial Agents ; Pneumococcal Vaccines
Language	English
Publishing date	2023-11-17
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-43160-y
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Article ; Online: A pragmatic health centre-based evaluation comparing the effectiveness of a PCV13 schedule change from 3+0 to 2+1 in a high pneumococcal carriage and disease burden setting in Malawi: a study protocol.

Swarthout, Todd D / Ibarz-Pavon, Ana / Kawalazira, Gift / Sinjani, George / Chirombo, James / Gori, Andrea / Chalusa, Peter / Bonomali, Farouck / Nyirenda, Roseline / Bulla, Edwin / Brown, Comfort / Msefula, Jacquline / Banda, Marjory / Kachala, Jean / Mwansambo, Charles / Henrion, Marc Yr / Gordon, Stephen B / French, Neil / Heyderman, Robert S

BMJ open

2021 Volume 11, Issue 6, Page(s) e050312

Abstract: Introduction: Streptococcus pneumoniae: Methods: A pragmatic health centre-based evaluation comparing impact of a PCV13 schedule change from 3+0 to 2+1 in Blantyre district, Malawi. Twenty government health centres will be randomly selected, with ten ...

Abstract	Introduction: Streptococcus pneumoniae Methods: A pragmatic health centre-based evaluation comparing impact of a PCV13 schedule change from 3+0 to 2+1 in Blantyre district, Malawi. Twenty government health centres will be randomly selected, with ten implementing a 2+1 and 10 to continue with the 3+0 schedule. Health centres implementing 3+0 will serve as the direct comparator in evaluating 2+1 providing superior direct and indirect protection against pneumococcal carriage. Pneumococcal carriage surveys will evaluate carriage prevalence among children 15-24 months, randomised at household level, and schoolgoers 5-10 years of age, randomly selected from school registers. Carriage surveys will be conducted 18 and 33 months following 2+1 implementation. Analysis: The primary endpoint is powered to detect an effect size of 50% reduction in vaccine serotype (VT) carriage among vaccinated children 15-24 months old, expecting a 14% and 7% VT carriage prevalence in the 3+0 and 2+1 arms, respectively. Ethics and dissemination: The study has been approved by the Malawi College of Medicine Research Ethics Committee (COMREC; Ref: P05.19.2680), the University College London Research Ethics Committee (Ref: 8603.002) and the University of Liverpool Research Ethics Committee (Ref: 5439). The results from this study will be actively disseminated through manuscript publications and conference presentations. Trial registration number: NCT04078997.
MeSH term(s)	Child ; Child, Preschool ; Humans ; Infant ; Carrier State/epidemiology ; Cost of Illness ; London ; Malawi/epidemiology ; Nasopharynx ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Pneumococcal Vaccines ; South Africa ; Streptococcus pneumoniae ; Vaccines, Conjugate ; Pragmatic Clinical Trials as Topic
Chemical Substances	Pneumococcal Vaccines ; Vaccines, Conjugate
Language	English
Publishing date	2021-06-17
Publishing country	England
Document type	Clinical Trial Protocol ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2599832-8
ISSN	2044-6055 ; 2044-6055
ISSN (online)	2044-6055
ISSN	2044-6055
DOI	10.1136/bmjopen-2021-050312
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Article ; Online: Impact and effectiveness of 13-valent pneumococcal conjugate vaccine on population incidence of vaccine and non-vaccine serotype invasive pneumococcal disease in Blantyre, Malawi, 2006-18: prospective observational time-series and case-control studies.

Bar-Zeev, Naor / Swarthout, Todd D / Everett, Dean B / Alaerts, Maaike / Msefula, Jacquline / Brown, Comfort / Bilima, Sithembile / Mallewa, Jane / King, Carina / von Gottberg, Anne / Verani, Jennifer R / Whitney, Cynthia G / Mwansambo, Charles / Gordon, Stephen B / Cunliffe, Nigel A / French, Neil / Heyderman, Robert S

The Lancet. Global health

2020 Volume 9, Issue 7, Page(s) e989–e998

Abstract: Background: The population impact of pneumococcal conjugate vaccines (PCVs) depends on direct and indirect protection. Following Malawi's introduction of the 13-valent PCV (PCV13) in 2011, we examined its impact on vaccine and non-vaccine serotype ... ...

Abstract	Background: The population impact of pneumococcal conjugate vaccines (PCVs) depends on direct and indirect protection. Following Malawi's introduction of the 13-valent PCV (PCV13) in 2011, we examined its impact on vaccine and non-vaccine serotype invasive pneumococcal disease among vaccine-eligible-age and vaccine-ineligible-age children and adults. Methods: We did a prospective observational time-series analysis and a case-control study. We used data from between Jan 1, 2006, and Dec 31, 2018, from laboratory-based surveillance at a government hospital in Malawi. This period included 6 years before and 7 years after introduction of PCV13. By use of negative-binomial regression, we evaluated secular trend-adjusted incidence rate ratio (IRR) in vaccine serotype and non-vaccine serotype invasive pneumococcal disease before and after introduction of PCV. We compared predicted counterfactual incidence in hypothetical absence of vaccine with empirically observed incidence following vaccine introduction. The case-control study assessed vaccine effectiveness, comparing PCV uptake among cases of vaccine-eligible-age invasive pneumococcal disease versus matched community controls. Findings: Surveillance covered 10 281 476 person-years of observation, with 140 498 blood and 63 291 cerebrospinal fluid cultures. A reduction in total (vaccine serotype plus non-vaccine serotype) invasive pneumococcal disease incidence preceded introduction of PCV: 19% (IRR 0·81, 95% CI 0·74 to 0·88, p<0·0001) among infants (<1 year old), 14% (0·86, 0·80 to 0·93, p<0·0001) among children aged 1-4 years, and 8% (0·92, 0·83 to 1·01, p=0·084) among adolescents and adults (≥15 years old). Among children aged 5-14 years there was a 2% increase in total invasive pneumococcal disease (1·02, 0·93 to 1·11, p=0·72). Compared with the counterfactually predicted incidence, incidence of post-PCV13 vaccine serotype invasive pneumococcal disease was 74% (95% CI 70 to 78) lower among children aged 1-4 years and 79% (76 to 83) lower among children aged 5-14 years, but only 38% (37 to 40) lower among infants and 47% (44 to 51) lower among adolescents and adults. Although non-vaccine serotype invasive pneumococcal disease has increased in incidence since 2015, observed incidence remains low. The case-control study (19 cases and 76 controls) showed vaccine effectiveness against vaccine serotype invasive pneumococcal disease of 80·7% (-73·7 to 97·9). Interpretation: In a high-mortality, high-HIV-prevalence setting in Africa, there were significant pre-vaccine reductions in the incidence of invasive pneumococcal disease. 7 years after PCV introduction, although vaccine-attributable impact among vaccine-eligible-age children was significant, indirect effects benefitting unvaccinated infants and adults were not. Policy decisions should consider multiple alternative strategies for reducing disease burden, including targeted vaccination outside infant Expanded Programme of Immunization to benefit vulnerable populations. Funding: Bill & Melinda Gates Foundation, Wellcome Trust, and National Institute for Health Research.
MeSH term(s)	Adolescent ; Adult ; Case-Control Studies ; Child ; Child, Preschool ; Female ; Humans ; Incidence ; Infant ; Malawi/epidemiology ; Male ; Pneumococcal Infections/epidemiology ; Pneumococcal Infections/prevention & control ; Pneumococcal Vaccines/administration & dosage ; Prospective Studies ; Serogroup ; Vaccines, Conjugate/administration & dosage
Chemical Substances	13-valent pneumococcal vaccine ; Pneumococcal Vaccines ; Vaccines, Conjugate
Language	English
Publishing date	2020-05-19
Publishing country	England
Document type	Journal Article ; Observational Study ; Research Support, Non-U.S. Gov't
ZDB-ID	2723488-5
ISSN	2214-109X ; 2214-109X
ISSN (online)	2214-109X
ISSN	2214-109X
DOI	10.1016/S2214-109X(21)00165-0
Database	MEDical Literature Analysis and Retrieval System OnLINE

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