A booster dose of the COVID-19 vaccine is safe, according to a study published in The Lancet Respiratory Medicine that monitored heart measurements using a smart watch. Researchers from Tel Aviv University equipped almost 5,000 Israelis with smart watches and monitored their physiological parameters over the course of two years.
Of those followed, 2,038 received a booster dose of the COVID-19 vaccine, allowing researchers to objectively compare participants’ pre- and post-vaccine measures and confirm the safety of the vaccine. The team also investigated the safety of the booster by anonymously analyzing the medical records of 250,000 members of Maccabi Health Services.
They were able to evaluate vaccine safety from three perspectives: subjectively what the participant reports, objectively what the watch detects, and clinically what the doctor diagnoses. “Smartwatches have been used to monitor a number of parameters such as heart rate, changes in cardiac activity, sleep quality, daily steps and more,” said Professor Dan Yamin of Tel Aviv University.
“After the vaccine, we saw clear and significant changes, such as an increase in heart rate compared to the heart rate measured before vaccination, and then we saw a return to the participant’s baseline value, i.e. the previous level after six days. So our study confirms the safety of the vaccine,” said Yamin.
The researchers said the most surprising finding was that the watches were more sensitive than the people they were watching. Many participants reported fatigue, headaches, etc., after receiving the vaccine and reported feeling normal and well after two or three days, they said.
“In contrast, when we examined their watches, we saw distinct changes in heart rate that continued for several days,” Yamin said. “There were also vaccinated participants who reported no side effects at all, yet definitely experienced physiological changes based on their smartwatch data. In other words, we learned that the smartwatch was more sensitive to changes in overall feeling than the participants themselves,” he added.
Twenty-five unusual side effects attributed to the COVID vaccine have been reported in the medical literature, and researchers have paid particular attention to looking for rare cases of inflammation of the heart muscle (myocarditis) and pericarditis. Researchers checked the frequency of these unusual side effects among a quarter of a million Maccabi members and found no increase in serious incidents of any kind associated with the vaccination.
