biostudies-literatureCallahan STNIAID NIH HHSPHS HHS1270-4https://www.ebi.ac.uk/biostudies/studies/S-EPMC4271072biostudies-literatureUnknown210(8)Obesity emerged as a risk factor for morbidity and mortality related to 2009 pandemic influenza A (H1N1) infection. However, few studies examine the immune responses to H1N1 vaccine among children and adults of various body mass indices (BMI). Pooling data from 3 trials of unadjuvanted split-virus H1N1 A/California/07/2009 influenza vaccines, we analyzed serologic responses of participants stratified by BMI grouping. A single vaccine dose produced higher hemagglutination inhibition antibody titers at day 21 in obese compared to nonobese adults, but there were no significant differences in responses to H1N1 vaccine among children or adults of various BMI following 2 doses.The Journal of infectious diseasesImpact of body mass index on immunogenicity of pandemic H1N1 vaccine in children and adults.PMC4271072HHSN272200800001OHHSN272200800004CHHSN27220080000CHHSN272200800001IHHSN272200800001GHHSN272200800001CHHSN272200800002CHHSN272200800013CFrenck RJackson LAShane AStapleton JBelshe RBAtmar RStephens ISchmader KBrady RFrey SERouphael NHutter JPatel SWhitaker JChen WLivingston RAGraham IJackson MAWalter EBernstein DWolff MEnglund JAWinokur PJohnston CWooten SEl Sahly HHill HRMulligan MJCreech CDolor RKeyserling HMyers AEdwards KMHealy SKotloff KGlezen WKeitel WEdupuganti SHarrison CMeier JMunoz FNewland JCallahan STEckard ARSwanson DCallahan SNIAID Vaccine and Treatment Evaluation Unit (VTEU) Pandemic H1N1 Vaccine Study GroupSpearman PAnderson EWald AfalseImpact of body mass index on immunogenicity of pandemic H1N1 vaccine in children and adults.Obesity emerged as a risk factor for morbidity and mortality related to 2009 pandemic influenza A (H1N1) infection. However, few studies examine the immune responses to H1N1 vaccine among children and adults of various body mass indices (BMI). Pooling data from 3 trials of unadjuvanted split-virus H1N1 A/California/07/2009 influenza vaccines, we analyzed serologic responses of participants stratified by BMI grouping. A single vaccine dose produced higher hemagglutination inhibition antibody titers at day 21 in obese compared to nonobese adults, but there were no significant differences in responses to H1N1 vaccine among children or adults of various BMI following 2 doses.2014-01-01T00:00:00Z2014 Oct2025-06-01T00:53:14.749Z2025-06-01T00:53:14.749ZS-EPMC42710722479547510.1093/infdis/jiu245