Delineating the serotype-specific neutralizing antibody response to a live attenuated tetravalent dengue vaccine

The dengue virus (DENV) vaccines that are licensed or in clinical development consist of DENV serotype 1–4 tetravalent formulations given simultaneously and are not acquired sequentially like natural infections. It is unclear what effect this has on development of protective levels of immunity to all four serotypes. Serotype-specific neutralizing antibody (NAb) is considered the most relevant correlate of protection from dengue disease. Here we assessed levels of serotype-specific and cross-reactive NAb in immune sera from 10 subjects vaccinated with a live attenuated tetravalent DENV vaccine developed at the Walter Reed Army Institute of Research. The majority of subjects NAb responses to DENV-2 and DENV-4 were type-specific, while their NAb responses to DENV-1 and DENV-3 were primarily cross-reactive. Vaccine virus RNAemia has been most frequently detected for DENV-2 and DENV-4 in vaccinated subjects, strongly suggesting that replication is important for eliciting serotype-specific immunity

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease