Safety of coronavirus disease 19 (COVID-19) vaccines has been a concern. Despite safety profile of different vaccines demonstrated in phase 2/3 trials, there has been evolving evidence on adverse effects of some particular COVID-19 vaccines. One of the mostly known example is vaccine-induced thrombotic thrombocytopenia (VITT). Apart from the thrombotic risk of ChAdOx1 nCoV-19 vaccine, there has been studies providing the preliminary data on effect of mRNA-based COVID-19 vaccine on blood pressure.~A case series report was published on Hypertension in June 2021 on documented stage III hypertension within minutes of vaccination (mRNA vaccines) in a vaccination centre located in Switzerland. The study reported 9 subjects experienced a surge in blood pressure to stage III hypertension after vaccination. Yet the study had a few shortcomings. There was not baseline measurement of blood pressure. Surge of blood pressure shortly after vaccination could be due to nervousness or white coat effect. Thus surge of blood pressure within minutes of vaccination could be not due to vaccination. There was not long-term follow-up on blood pressure measurement after vaccination.~Further to the case series report, another prospective study in Italy investigated effect of mRNA vaccine on blood pressure and heart rate. The study was conducted as a survey. There was 5.3% of respondents (6/113) reported rise of home blood pressure of at least 10mmHg after 1st dose vaccination, compared with home blood pressure prior to vaccination. Among these subjects, 4 of them required anti-hypertensive medication intensification.~Yet there remains lack of evidence and detailed description on effect of COVID-19 vaccines and blood pressure before and after vaccination. Use of ambulatory blood pressure monitoring (ABPM) before and after vaccination helps to understand the details on short-term blood pressure changes.
To investigate short-term effect of COVID-19 vaccination on blood pressure by conducting 24-hour ABPM