We have read with interest the letter from Pathum Sookaromdee et al., in reference to our manuscript “Tachycardia as an adverse effect not described in the Comirnaty© vaccine (COVID-19 mRNA BNT162b2 vaccine from Pfizer-BioNTech): description of 3 cases with a history of SARS-CoV-2”, and we would like to make the following clarifications:
Regarding their comment that in order to conclude that an adverse effect is due to the vaccine, a medical condition must be ruled out, our manuscript reports 3 cases of patients who presented tachycardia after the Pfizer-BioNTech COVID-19 vaccine. In none of the 3 cases was there a personal history of previous heart disease and the tachycardia appeared between 10 and 15 h after the administration of the vaccine, resolving spontaneously in less than 36 h, therefore, there is a temporal association between the administration of the vaccine and the onset of the symptom. Only in case 3 was a study carried out by the Cardiology department because the patient also presented symptomatic extrasystoles maintained over time. The cardiology study consisted of an electrocardiogram and an echocardiogram with normal results, thus ruling out structural heart disease. The patient remained asymptomatic from the extrasystoles one month after the start of treatment with bisoprolol.
Since the publication of our manuscript, there have been numerous articles that describe this adverse effect after the administration of the Comirnaty vaccine. Tate et al. describe the case of a 29-year-old woman who suffered sinus tachycardia of up to 135 bpm as the only adverse event that appeared 6−8 h after the administration of the second dose of the vaccine and resolved in 24 h.1 The onset of tachycardia has also been described in the context of postural orthostatic tachycardia syndrome.2
Recently (04/21/2022), Pfizer-BioNTech published the report of cases of analysis of adverse effects secondary to its COVID-19 vaccine, which describes all the cases reported in the United Kingdom during the period from 12/09/2020 to 04/20/2022.3 In said report, tachycardia was described in 2,449 cases, in no case fatal.
In our case, and as in the Pfizer-BioNTech report, it is a suspected post-vaccination adverse reaction.
