A new study by researchers from the Vall d'Hebron Research Institute (VHIR) group on http://en.vhir.org/portal1/grup-equip.asp?s=recerca&contentid=186985 Epidemiology and Public Health, led by Dr. Magda Campins shows the complications that flu entails in pregnant women, which reaffirms the importance of influenza vaccination in this group. The study analyzed two parameters, the number of visits to Primary Care and the number of hospitalizations, in a sample of more than 200,000 pregnant women in Catalonia between 2008 and 2013.During pregnancy there are a series of physiological changes such as increased heart rate, decreased pulmonary capacity and immunodeficiency related to hormonal changes. Therefore, during pregnancy, if the woman suffers from a flu, the risk of complications such as bacterial pneumonia (pneumococcal) or viral (influenza virus) is greater. On the other hand, cardiovascular complications derived from hemodynamic disorders can also appear, especially in the third trimester of pregnancy.These physiological changes help make pregnancy a risk factor for complications during the flu process. And, as shown in this study, published in the https://www.journalofinfection.com/article/S0163-4453(18)30211-1/fulltext Journal of Infection, pregnant women recorded a number of visits to Primary Care (AP) and hospitalizations higher than in the previous year, when they were not pregnant.Visits to Primary Care always increase during the flu season in all population groups and the same applies to pregnant women. "If we compare it with the same period during the previous year, when they were not pregnant, the study observed an increase in the demand for consultations for respiratory or cardiac problems. The higher probability of Primary Care consultations was mainly during the first and second trimesters of gestation and in those women who presented comorbidities (gestational diabetes, asthma, heart disease and/or chronic respiratory diseases, etc.)", explains Dr. Magda Campins, Head of the Preventive Medicine and Epidemiology Service at Vall d'Hebron Hospital and head of the Epidemiology and Public Health research group at VHIR.In the case of hospitalizations, it is during the third trimester when the risk of being admitted to hospital for a cardio-respiratory type complication is greater and it is also related to the presence of comorbidities.Among the immigrant population, the number of visits to Primary Care was lower than in the local population, and the number of hospitalizations was very similar.In fact, during the influenza pandemics at the beginning of the last century and during the influenza A (H1N1) pandemic in 2009, the risk of complications and hospitalizations in pregnant women was shown to be higher than that in the general population and similar to that in the population traditionally considered to be at risk (elderly people, with cardiac problems, immunodeficient people). "For this reason, since 2007, influenza vaccination is recommended for pregnant women at any time during pregnancy, as long as it coincides with the flu season", explains Dr. Campins.Flu vaccine is safe for both the mother and the baby. And it is very important to remember that not only can it prevent complications in the pregnant woman, but it can also protect the baby until the first six months of life thanks to the transplacental passage of maternal antibodies.The pilot project DRIVEResearchers from the Epidemiology and Public Health and Microbiology research groups at VHIR participate in a multicenter European study to evaluate the effectiveness of influenza vaccines.The World Health Organization and the European Medicines Agency intend to standardize the methodology to evaluate the effectiveness of influenza vaccines of different brands and, for that reason, the researchers involved are independent groups, not linked to the pharmaceutical industry.Vall d'Hebron is the only Catalan center that participates in this project, which is coordinated at a state level by FISABIO (Foundation for the Promotion of Health and Biomedical Research of Valencia Region).