ABSTRACT
COVID-19 remains a global concern due to vaccine protection waning and the emergence of immuneevasive variants. While the effectiveness of a second booster vaccine dose (i.e., fourth inoculation) is well proven, its safety has yet to be fully understood, and vaccine compliance remains low. We conducted a prospective observational study to compare the short-term effects of the first and second BNT162b2 mRNA COVID-19 vaccine booster doses. 2,019 participants received smartwatches and filled in a daily questionnaire on systemic reactions to the vaccine. We found substantial changes from baseline levels in the 72 hours post-vaccination with the second booster in both self-reported and physiological reactions measured by the smartwatches. However, no significant difference in reactions was observed between the first and second boosters. We also found that participants who experienced more severe reactions to the first booster tended to likewise experience more severe reactions to the second booster. Our work supports the safety of the second booster from both subjective (self-reported questionnaires) and objective (physiological measurements) perspectives.
ABSTRACT
BackgroundThe rapid rise in hospitalizations associated with the Delta-driven COVID-19 resurgence, and the imminent risk of hospital overcrowding, led the Israeli government to initialize a national third (booster) COVID-19 vaccination campaign in early August 2021, offering the BNT162b2 mRNA vaccine to individuals who received their second dose over five months ago. However, the safety of the third (booster) dose has not been fully established yet. ObjectiveEvaluate the short-term, self-reported and physiological reactions to the third BNT162b2 mRNA COVID-19 (booster) vaccine dose. DesignA prospective observational study, in which participants are equipped with a smartwatch and fill in a daily questionnaire via a dedicated mobile application for a period of 21 days, starting seven days before the vaccination. SettingAn Israel-wide third (booster) vaccination campaign. ParticipantsA group of 1,609 (18+ years of age) recipients of at least one dose of the BNT162b2 vaccine between December 20, 2020, and September 15, 2021, out of a larger cohort of 2,912 prospective study participants. 1,344 of the participants were recipients of the third vaccine dose. MeasurementsDaily self-reported questionnaires regarding local and systemic reactions, mood level, stress level, sport duration, and sleep quality. Heart rate, heart rate variability and blood oxygen saturation level were continuously measured by Garmin Vivosmart 4 smartwatches. ResultsThe extent of systemic reactions reported following the third (booster) dose administration is similar to that reported following the second dose (p-value=0.305) and considerably greater than that reported following the first dose (p-value<0.001). Our analyses of self-reported well-being indicators as well as the objective heart rate and heart rate variability measures recorded by the smartwatches further support this finding. Focusing on the third dose, reactions were more apparent in younger participants (p-value<0.01), in women (p-value<0.001), and in participants with no underlying medical conditions (p-value<0.001). Nevertheless, reported reactions and changes in physiological measures returned to their baseline levels within three days from inoculation with the third dose. LimitationsParticipants may not adequately represent the vaccinated population in Israel and elsewhere. ConclusionOur work further supports the safety of a third COVID-19 BNT162b2 mRNA (booster) vaccine dose from both a subjective and an objective perspective, particularly in individuals 65+ years of age and those with underlying medical conditions. Primary funding sourceEuropean Research Council (ERC) project #949850
ABSTRACT
BackgroundClinical trial guidelines for assessing the safety of vaccines, including the FDA criteria, are primarily based on subjective, self-reported questionnaires. Despite the tremendous technological advances in recent years, objective, continuous assessment of physiological measures post-vaccination is rarely performed. MethodsTo evaluate the short-term effects of the BNT162b2 COVID-19 vaccine on physiological measures, we conducted a prospective observational study during the mass vaccination campaign in Israel. 160 individuals >18 years who were not previously found to be COVID-19 positive and who received the second dose of the COVID-19 vaccine between 1 January, 2021, and 13 March, 2021 were equipped with a chest-patch sensor and a dedicated mobile application. The chest-patch sensor continuously measured 13 physiological vitals one day before the inoculation (baseline), for four days: heart rate, blood oxygen saturation, respiratory rate, systolic and diastolic blood pressure, pulse pressure, mean arterial pressure, heart rate variability, stroke volume, cardiac output, cardiac index, systemic vascular resistance, and body temperature. The mobile application collected daily self-reported questionnaires starting one day before the inoculation, for 15 days on local and systemic reactions, sleep quality, stress levels, physical activity, and mood levels. FindingsWithin the first 48 hours post-vaccination, we identified significant changes (p-value <0.05) in nearly all 13 chest-patch indicators compared to their baseline levels. 48.5% (n=78) reported no local or systemic reaction. Nevertheless, we identified considerable changes in chest-patch indicators during the first 48 hours post-vaccination also in this group of presumably asymptomatic participants. Within three days from vaccination, these measures returned to baseline levels in both groups, further supporting the safety of the vaccine. InterpretationOur work underscores the importance of obtaining objective physiological data in addition to self-reported questionnaires when performing clinical trials, particularly in ones conducted in very short time frames. FundingThe European Research Council (ERC) project #949850.
