This week Vall d'Hebron has started recruiting volunteers to participate in the phase III clinical trial of the Covid-19 vaccine from Janssen Pharmaceuticals (Johnson & Johnson). This is the first trial of this characteristics that has been authorized in the State and in the coming days the Preventive Medicine and Epidemiology Service of Vall d'Hebron will administer the vaccine to the first volunteers.Last November, Agencia Española de Medicamentos y Productos Sanitarios (AEMPS) authorized the ENSEMBLE 2 trial to evaluate the efficacy and safety of the vaccine in both healthy volunteers and participants with concomitant diseases that are associated with a higher risk of progression to severe Covid-19.This is a trial that will include up to 30,000 volunteers from 9 countries (Belgium, Colombia, France, Germany, South Africa, the Philippines, Spain, the United Kingdom and the United States) and in which, in addition to the Vall d'Hebron University Hospital involves 7 other hospitals in Spain (Vall d'Hebron University Hospital, Hospital Clínic de Barcelona, Quirónsalud Hospital in Barcelona, Germans Trias i Pujol University Hospital in Badalona, Hospital University of the Princess of Madrid, the University Hospital La Paz of Madrid and the Hospital Quirónsalud of Madrid and the Clinic University of Navarre).Volunteers will receive two doses of the vaccine.Profile of volunteersTo participate in the study, the prerequisite is to be over 18 years old.People who will not be able to participate:People immunocompromised by a underlying disease or on treatment with immunosuppressive drugs.Women who are pregnant or are likely to become pregnant in the next two years.People with a history of anaphylaxis or severe adverse reactions to vaccines.People already participating in other clinical trials.Type of vaccineThe vaccine, called Ad26.COV2.S, does not contain the living virus, it uses an artificial protein from the virus for the body to generate antibodies. It is based on a solidly documented technology with a non-replicating recombinant adenovirus that acts as a vector to generate an immune response to one of the coronavirus proteins known as the S protein (spike) which is the one used by the virus to attach to the person's cells.Type of clinical trialThis is a randomized, double-blind, placebo-controlled study. This means that randomly, half of the participants are given the vaccine and the other half the masked placebo in such a way that neither the healthcare staff nor the volunteer can identify what is being given.This trial will study the safety and efficacy in a two-dose regimen of the vaccine that will be injected with a 57-day difference between the first and second dose. Volunteers will be monitored for 2 years.Throughout the trial, close monitoring of all volunteers and identification of all Covid-19 cases that occur will be performed. This will make it possible to carry out preliminary analyzes with intermediate data. However, it will be necessary to wait until the clinical trial has been completed in order to analyze all the data and draw final conclusions."Although two vaccines have already been authorized against Covid-19, it is essential to continue developing other candidate vaccines in order to guarantee greater availability and also to be able to outline strategies adjusted to each population group according to the type of vaccine", explains the Dra. Susana Otero, researcher in the study, assistant doctor of the Preventive Medicine and Epidemiology Service of the Vall d'Hebron University Hospital and principal investigator of the research group in Epidemiology and Public Health of the Vall d'Hebron Research Institute (VHIR)."The participation of volunteers in an altruistic way in clinical trials is essential to be able to advance in the research, not only of vaccines, but also of any new medicine. It is an act of solidarity towards the population and reflects the contribution of society in the advancement of medicine, as important in a situation of health crisis as the one we are experiencing", concludes Dr. Magda Campins, principal investigator in this study, head of the Preventive Medicine and Epidemiology Service at Vall d'Hebron University Hospital and head of the research group in Epidemiology and Public Health at the VHIR.