Featured Publications
Pneumococcal infections in children with sickle cell disease before and after pneumococcal conjugate vaccines
Adamkiewicz T, Yee M, Thomas S, Tunali A, Lai K, Omole F, Lane P, Yildirim I. Pneumococcal infections in children with sickle cell disease before and after pneumococcal conjugate vaccines. Blood Advances 2023, 7: 6751-6761. PMID: 37698500, PMCID: PMC10660014, DOI: 10.1182/bloodadvances.2022009643.Peer-Reviewed Original ResearchConceptsInvasive pneumococcal diseaseSickle cell diseaseCell diseasePCV13-serotype invasive pneumococcal diseaseSerotype invasive pneumococcal diseaseNon-PCV13 serotypesPneumococcal polysaccharide vaccinePneumococcal conjugate vaccineIncidence rate ratiosYears of vaccinationReference populationLife-threatening risksIPD episodesIPD serotypesPneumococcal diseasePneumococcal infectionPolysaccharide vaccineConjugate vaccineHemoglobin SSVaccine licensureEffective vaccinePenicillin resistanceDisease controlVaccineAfrican American childrenCOVID-19 Vaccine Acceptance and Hesitancy Among Health Care Workers in Lebanon
Youssef N, Tfaily N, Moumneh M, Boutros C, Elharake J, Malik A, McFadden S, Galal B, Yildirim I, Khoshnood K, Omer S, Memish Z, Dbaibo G. COVID-19 Vaccine Acceptance and Hesitancy Among Health Care Workers in Lebanon. Journal Of Epidemiology And Global Health 2023, 13: 55-66. PMID: 36735184, PMCID: PMC9896451, DOI: 10.1007/s44197-023-00086-4.Peer-Reviewed Original ResearchConceptsHealth care workersCOVID-19 vaccine acceptanceVaccine acceptancePrevious infectionCare workersPrevious SARS-CoV-2 infectionSARS-CoV-2 infectionMethodsA cross-sectional studyCOVID-19 vaccination ratesCOVID-19 vaccinationCross-sectional studyCOVID-19 vaccineHealth care authoritiesVaccine uptakeVaccination ratesOrder of PhysiciansVaccine hesitancyGeneral populationHealthcare providersVaccineCare authoritiesInfectionCOVID-19 informationTrusted sourceCOVID-19 pandemic
2024
Immunogenicity of Current and Next-Generation Pneumococcal Conjugate Vaccines in Children: Current Challenges and Upcoming Opportunities
Feemster K, Buchwald U, Banniettis N, Joyce J, Velentgas P, Chapman T, Yildirim I. Immunogenicity of Current and Next-Generation Pneumococcal Conjugate Vaccines in Children: Current Challenges and Upcoming Opportunities. Open Forum Infectious Diseases 2024, 11: ofae220. PMID: 38770212, PMCID: PMC11103622, DOI: 10.1093/ofid/ofae220.Peer-Reviewed Original ResearchA Phase 1, Double-Blinded, Placebo-Controlled Clinical Trial to Evaluate the Safety and Immunogenicity of HEV-239 (Hecolin) Vaccine in Healthy US Adults
Kao C, Rostad C, Nolan L, Peters E, Kleinhenz J, Sherman J, Tippett A, Shih J, Yildirim I, Agbakoba V, Beresnev T, Ballou C, Kamidani S, Karmali V, Natrajan M, Scherer E, Rouphael N, Anderson E. A Phase 1, Double-Blinded, Placebo-Controlled Clinical Trial to Evaluate the Safety and Immunogenicity of HEV-239 (Hecolin) Vaccine in Healthy US Adults. The Journal Of Infectious Diseases 2024, 230: 1093-1101. PMID: 38536442, PMCID: PMC11565884, DOI: 10.1093/infdis/jiae148.Peer-Reviewed Original ResearchHealthy US adultsDouble-blindThird dosePlacebo-Controlled Clinical TrialSystemic reactionsHepatitis E virus vaccineUS adultsHepatitis E vaccinePlacebo groupPlacebo-controlledAdverse eventsE vaccineSecond doseClinical trialsDay 1Immune responseDosePhase 1ImmunogenicityMonthsSafety studiesVaccineInfant mortalityTrialsAdults
2023
Age-dependent impairment in antibody responses elicited by a homologous CoronaVac booster dose
Filardi B, Monteiro V, Schwartzmann P, do Prado Martins V, Zucca L, Baiocchi G, Malik A, Silva J, Hahn A, Chen N, Pham K, Pérez-Then E, Miric M, Brache V, Cochon L, Larocca R, Della Rosa Mendez R, Silveira D, Pinto A, Croda J, Yildirim I, Omer S, Ko A, Vermund S, Grubaugh N, Iwasaki A, Lucas C, Initiative Y, Vogels C, Breban M, Koch T, Chaguza C, Tikhonova I, Castaldi C, Mane S, De Kumar B, Ferguson D, Kerantzas N, Peaper D, Landry M, Schulz W. Age-dependent impairment in antibody responses elicited by a homologous CoronaVac booster dose. Science Translational Medicine 2023, 15: eade6023. PMID: 36791210, DOI: 10.1126/scitranslmed.ade6023.Peer-Reviewed Original ResearchConceptsBooster doseAntibody responseNeutralization titersVirus-specific IgG titersOlder adultsAntiviral humoral immunityPlasma antibody responsesHigh-risk populationSARS-CoV-2 spikeYears of ageAge-dependent impairmentHeterologous regimensBooster dosesBooster vaccineCoronaVac vaccineIgG titersProtective immunityHumoral immunityHumoral responseCoronaVacOmicron waveBooster strategyAge groupsEarly controlVaccine
2022
The balancing role of distribution speed against varying efficacy levels of COVID-19 vaccines under variants
Kim D, Keskinocak P, Pekgün P, Yildirim İ. The balancing role of distribution speed against varying efficacy levels of COVID-19 vaccines under variants. Scientific Reports 2022, 12: 7493. PMID: 35523832, PMCID: PMC9075929, DOI: 10.1038/s41598-022-11060-8.Peer-Reviewed Original ResearchConceptsOverall public health impactInfection attack rateCOVID-19 vaccineSARS-CoV-2Public health impactVaccine effectivenessAdverse outcomesMultiple vaccinesInitial efficacySuccessful immunization strategyImmunization strategiesVaccineLow-income countriesAttack rateEfficacyCOVID-19COVID-19 pandemicHealth impactsInfection spreadRecovered-deceased [SI(Q/F)RD] modelEfficacy levelsPandemicHospitalizationVaccinationVariantsNeutralizing antibodies against the SARS-CoV-2 Delta and Omicron variants following heterologous CoronaVac plus BNT162b2 booster vaccination
Pérez-Then E, Lucas C, Monteiro VS, Miric M, Brache V, Cochon L, Vogels CBF, Malik AA, De la Cruz E, Jorge A, De los Santos M, Leon P, Breban MI, Billig K, Yildirim I, Pearson C, Downing R, Gagnon E, Muyombwe A, Razeq J, Campbell M, Ko AI, Omer SB, Grubaugh ND, Vermund SH, Iwasaki A. Neutralizing antibodies against the SARS-CoV-2 Delta and Omicron variants following heterologous CoronaVac plus BNT162b2 booster vaccination. Nature Medicine 2022, 28: 481-485. PMID: 35051990, PMCID: PMC8938264, DOI: 10.1038/s41591-022-01705-6.Peer-Reviewed Original ResearchConceptsTwo-dose regimenOmicron variantVaccine boosterMRNA vaccinesNeutralization activityDelta variantTwo-dose mRNA vaccinesVirus-specific antibody levelsSARS-CoV-2 Omicron variantMRNA vaccine boosterNeutralization of OmicronNumerous spike mutationsSARS-CoV-2 DeltaPotent neutralization activityInfection-induced immunityCOVID-19 vaccineBNT162b2 boosterBooster vaccinationPrime vaccinationAntibody levelsAntibody titersHumoral immunityImmune escapeInactivated vaccinesVaccine
2021
Resource allocation for different types of vaccines against COVID-19: Tradeoffs and synergies between efficacy and reach
Kim D, Pekgün P, Yildirim İ, Keskinocak P. Resource allocation for different types of vaccines against COVID-19: Tradeoffs and synergies between efficacy and reach. Vaccine 2021, 39: 6876-6882. PMID: 34688498, PMCID: PMC8520874, DOI: 10.1016/j.vaccine.2021.10.025.Peer-Reviewed Original ResearchConceptsInfection attack rateVaccine typesDifferent vaccine typesResource-limited countriesHigh-efficacy vaccinesDifferent study parametersVaccine shortageEfficacy vaccineHealth outcomesLife-saving vaccinesVaccineVaccine distributionLow efficacyAttack rateStudy parametersEfficacyHigh efficacyCOVID-19COVID-19 pandemicDeceased (SIRD) modelDifferent resource allocation decisionsLimited accessCOVID-19 vaccine acceptance among healthcare workers in the United Arab Emirates
AlKetbi LMB, Elharake JA, Memari SA, Mazrouei SA, Shehhi BA, Malik AA, McFadden SM, Galal B, Yildirim I, Khoshnood K, Omer SB, Memish ZA, AlZarouni AA, AlNeyadi AM, Hosani FA. COVID-19 vaccine acceptance among healthcare workers in the United Arab Emirates. IJID Regions 2021, 1: 20-26. PMID: 35721775, PMCID: PMC8505903, DOI: 10.1016/j.ijregi.2021.08.003.Peer-Reviewed Original ResearchCOVID-19 vaccine acceptanceVaccine acceptanceHealthcare workersCOVID-19 vaccineHCW populationVaccine hesitancyCOVID-19 vaccine informationPublic health messaging campaignsCOVID-19 vaccine concernsCOVID-19 vaccine hesitancyYears of agePhysicians/surgeonsWorld Health OrganizationSimple logistic regressionVaccine informationVaccine concernsGeneral populationPatient decisionHealthcare providersInfection riskLogistic regressionHealthcare authoritiesHealth officialsHealth OrganizationVaccineCOVID-19 Vaccine Acceptance among Health Care Workers in the Kingdom of Saudi Arabia
Elharake JA, Galal B, Alqahtani SA, Kattan RF, Barry MA, Temsah MH, Malik AA, McFadden SM, Yildirim I, Khoshnood K, Omer SB, Memish ZA. COVID-19 Vaccine Acceptance among Health Care Workers in the Kingdom of Saudi Arabia. International Journal Of Infectious Diseases 2021, 109: 286-293. PMID: 34242765, PMCID: PMC8260488, DOI: 10.1016/j.ijid.2021.07.004.Peer-Reviewed Original ResearchConceptsHealth care workersCOVID-19 vaccineCOVID-19 vaccine acceptanceVaccine acceptanceCare workersPublic health messaging campaignsCOVID-19 vaccine concernsPotential side effectsHealth care authoritiesVaccine concernsGeneral populationSide effectsVaccineCare authoritiesSaudi ArabiaHealth officialsMessaging campaignsDemographic characteristicsCOVID-19 informationKSA MinistryDemographic differencesParticipantsSignificance of SARS-CoV-2 specific antibody testing during COVID-19 vaccine allocation
Fujimoto AB, Keskinocak P, Yildirim I. Significance of SARS-CoV-2 specific antibody testing during COVID-19 vaccine allocation. Vaccine 2021, 39: 5055-5063. PMID: 34274126, PMCID: PMC8233959, DOI: 10.1016/j.vaccine.2021.06.067.Peer-Reviewed Original ResearchConceptsInfection attack rateAntibody testingSARS-CoV-2-specific antibodiesSpecific antibody testingAttack rateCOVID-19 vaccineSingle-dose vaccineCOVID-19 vaccine allocationDose vaccineSerology testingLimited vaccinesEligible individualsVaccine deploymentVaccination planVaccine supplySusceptible individualsNumber of casesRecovered (SIR) compartmental modelPeak dayUse of antibodiesVaccine allocationVaccinePeak infectionVaccinationSpecific antibodies
2020
Herd Immunity and Implications for SARS-CoV-2 Control
Omer SB, Yildirim I, Forman HP. Herd Immunity and Implications for SARS-CoV-2 Control. JAMA 2020, 324: 2095-2096. PMID: 33074293, DOI: 10.1001/jama.2020.20892.Peer-Reviewed Original ResearchThe VACCINES Act: Deciphering Vaccine Hesitancy in the Time of COVID-19
McAteer J, Yildirim I, Chahroudi A. The VACCINES Act: Deciphering Vaccine Hesitancy in the Time of COVID-19. Clinical Infectious Diseases 2020, 71: 703-705. PMID: 32282038, PMCID: PMC7184475, DOI: 10.1093/cid/ciaa433.Peer-Reviewed Original ResearchConceptsSevere acute respiratory syndrome coronavirus 2Acute respiratory syndrome coronavirus 2Respiratory syndrome coronavirus 2Syndrome coronavirus 2Vaccines actCoronavirus 2Clinical trialsVaccine hesitancyVaccine candidatesNovel vaccinesCOVID-19COVID-19 pandemicVaccineTimes of COVID19PandemicTrials
2019
Effect of Concomitant Antibiotic and Vaccine Administration on Serologic Responses to Rotavirus Vaccine
Anderson EJ, Lopman B, Yi J, Libster R, Creech CB, El-Khorazaty J, Baqar S, Yildirim I, Kao C, Rouphael N, Shane AL, Edwards K. Effect of Concomitant Antibiotic and Vaccine Administration on Serologic Responses to Rotavirus Vaccine. Journal Of The Pediatric Infectious Diseases Society 2019, 9: 479-482. PMID: 31237948, PMCID: PMC7495907, DOI: 10.1093/jpids/piz044.Peer-Reviewed Original Research
2018
The relative invasive disease potential of Streptococcus pneumoniae among children after PCV introduction: A systematic review and meta-analysis
Balsells E, Dagan R, Yildirim I, Gounder PP, Steens A, Muñoz-Almagro C, Mameli C, Kandasamy R, Lavi N, Daprai L, van der Ende A, Trzciński K, Nzenze SA, Meiring S, Foster D, Bulkow LR, Rudolph K, Valero-Rello A, Ducker S, Vestrheim DF, von Gottberg A, Pelton SI, Zuccotti G, Pollard AJ, Sanders EAM, Campbell H, Madhi SA, Nair H, Kyaw MH. The relative invasive disease potential of Streptococcus pneumoniae among children after PCV introduction: A systematic review and meta-analysis. Journal Of Infection 2018, 77: 368-378. PMID: 29964140, DOI: 10.1016/j.jinf.2018.06.004.Peer-Reviewed Original ResearchConceptsInvasive pneumococcal diseaseInvasive disease potentialPneumococcal conjugate vaccineNon-vaccine typesPCV introductionPneumococcal diseaseClinical syndromePneumococcal serotypesSurveillance of IPDDisease potentialSystematic reviewCurrent pneumococcal conjugate vaccinesYears of ageRandom-effects modelConjugate vaccineRoutine immunisationDisease presentationFuture vaccinesStreptococcus pneumoniaeSerotype 1SerotypesSyndromeCarriageChildrenVaccine
2017
A fully liquid DTaP-IPV-HB-PRP-T hexavalent vaccine for primaryand booster vaccination of healthy Turkish infants and toddlers*
Ceyhan M, Yıldırım İ, Tezer H, Devrim İ, Feroldi E. A fully liquid DTaP-IPV-HB-PRP-T hexavalent vaccine for primaryand booster vaccination of healthy Turkish infants and toddlers*. Turkish Journal Of Medical Sciences 2017, 47: 1247-1256. PMID: 29156870, DOI: 10.3906/sag-1609-62.Peer-Reviewed Original ResearchDTaP-IPVHB-PRPT vaccineT-BoostersPrimary seriesAnti-HBs seroprotectionLiquid DTaP-IPVT hexavalent vaccineOpen-label trialMIU/mLMonths of ageHealthy Turkish infantsAntibody persistenceBooster responseBooster vaccinationHB vaccinationControl vaccineHexavalent vaccineSeroconversion ratesTurkish infantsSeroprotectionVaccinePhase IIIParental reportsNoninferiority
2015
Pneumococcal Disease in the Era of Pneumococcal Conjugate Vaccine
Yildirim I, Shea KM, Pelton SI. Pneumococcal Disease in the Era of Pneumococcal Conjugate Vaccine. Infectious Disease Clinics Of North America 2015, 29: 679-697. PMID: 26610421, PMCID: PMC4662776, DOI: 10.1016/j.idc.2015.07.009.Peer-Reviewed Original ResearchConceptsPneumococcal conjugate vaccinePneumococcal diseaseConjugate vaccineOtitis mediaUniversal immunizationAcute otitis mediaInvasive pneumococcal diseaseCase fatality rateVulnerable pediatric patientsSpectrum of serotypesCause pneumoniaPediatric patientsComorbid conditionsHealthy childrenFatality rateDiseaseHost susceptibilityImmunizationVaccineHigh rateChildrenEmpyemaMastoiditisPneumoniaPatients
2009
Multicenter Prospective Study on the Burden of Rotavirus Gastroenteritis in Turkey, 2005–2006: A Hospital-Based Study
Ceyhan M, Alhan E, Salman N, Kurugol Z, Yildirim I, Celik U, Keser M, Koturoglu G, Tezer H, Bulbul EK, Karabocuoglu M, Halicioglu O, Anis S, Pawinski R. Multicenter Prospective Study on the Burden of Rotavirus Gastroenteritis in Turkey, 2005–2006: A Hospital-Based Study. The Journal Of Infectious Diseases 2009, 200: s234-s238. PMID: 19817603, DOI: 10.1086/605056.Peer-Reviewed Original ResearchConceptsRotavirus gastroenteritisWorld Health Organization's generic protocolRotavirus-positive childrenPrevalence of rotavirusMulticenter prospective studyRotavirus vaccineProspective surveillanceProspective studyDisease burdenMortality rateGastroenteritisPrevalent strainsRotavirusIndividual centersChildrenBurdenMain causeHospitalizationHospitalInfantsVaccineYearsPrevalence