Vall d’Hebron begins the clinical trial in pregnant women of the Pfizer and BioNTech vaccine against COVID-19

The study will evaluate the safety, immunogenicity and efficacy of the vaccine in pregnant women, the passive transfer of antibodies to the fetus and the protection conferred during lactation.


Vall d’Hebron University Hospital has begun the clinical trial of the Pfizer-BioNTech COVID-19 (BNT162b2) vaccine to prevent COVID-19 in healthy pregnant women over 18 years old. It is the same vaccine that is already on the market and is being administered to the population in our country and in other countries. This study will evaluate the safety, immunogenicity and efficacy of the vaccine in this group, as well as the passive transfer of antibodies in the fetus and the protection conferred during lactation. The study will be conducted in 52 centers in the United States, Brazil, Mozambique, South Africa, the United Kingdom and Spain. In the State, together with Vall d'Hebron, Hospital de la Santa Creu i Sant Pau (Barcelona), Hospital Puerta del Sur (Madrid), l’Hospital HM Madrid, Hospital Clínico Universitario de Santiago de Compostela, Hospital de Antequera (Málaga) and Instituto Hispalense de Pediatria (Sevilla) will participate.

A recent international study, with the participation of the Obstetrics Service in Vall d'Hebron University Hospital, has shown that pregnant women have a higher risk of developing severe forms of COVID-19, with a higher risk of admission to the ICU, the need for mechanical ventilation and even premature termination of pregnancy. The same service is also a reference in the management of pregnant women with SARS-CoV-2 infection, which allowed them also to describe a specific complication similar to pre-eclampsia in pregnant women with severe pneumonia. Therefore, it is essential to have a vaccine that is safe and effective for pregnant women.

This is a randomized, double-blind, placebo-controlled study with a follow-up duration of up to 6 months after delivery. The vaccine will be administered according to the usual two-dose schedule 21 days apart. This trial will involve healthy pregnant women aged 18 years or older who will be vaccinated from the 27th week of gestation.

The trial will also study the safety and transfer of potentially protective antibodies in newborns, who will be monitored until approximately six months of age. According to the study protocol, one month after delivery, the study blind is opened and those women who were in the placebo group will receive the vaccine.

Pregnant women who are interested in participating in the study can contact the research team via the following email:

Pfizer and BioNTech are also planning to begin additional studies in children between the ages of 5 and 11 in the coming months, and in children under 5 years of age throughout 2021.

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