Reply: Coronavirus disease 2019 vaccines in pregnancy

We would like to thank Dr Al-Lami for his interest in our article. Given the lack of available data on the use of vaccines in pregnancy to date, we agree that pregnant women should weigh their own personal risk of coronavirus disease 2019 (COVID-19) exposure and disease severity. Furthermore, pregnant individuals should be aware of the significant maternal risks that COVID-19 poses.¹ The letter has made us realize about the theoretical concern of increased contractions related to the impairment of the angiotensin-converting enzyme (ACE) receptor. We are aware that there are no data suggesting that the mRNA vaccines down-regulate ACE receptors. In vaccine clinical trials, there was no exclusion of individuals using ACE inhibitors or ACE2 receptor antagonists for hypertension or was there any concern raised or complication for individuals with hypertension.

The mechanism of action of mRNA-based vaccines is to induce cellular and humoral immune responses. Furthermore, such vaccines do not contain a live virus. In addition, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine recommend that given the clear maternal benefits provided by vaccines in the absence of known harm, pregnant women should have access to these COVID-19 vaccines in all phases of vaccine distribution.² Given the lack of inclusion of pregnant women in vaccine clinical trials, we acknowledge that long-term maternal, fetal, and neonatal impacts are unknown because of the lack of available data. For this reason, collecting data through observational studies; surveillance systems, such as V-safe; and clinical trials aimed at enrolling pregnant women is important, to appropriately counsel individuals in the preconception, antepartum, and postpartum periods.