Since the start of the rollout, researchers had been asking everyone who gets vaccinated to log their jab, so that they can understand more about the impact of the new COVID-19 vaccines and their effects.
In addition to asking people to log daily reports about their general health for a week after vaccination, which captures information about the impact of the vaccine on the whole body (systemic effects), the app’s researchers are also asking about pain and swelling at the injection site.
To provide a picture of the most common side effects being reported, the data team analysed reports from nearly 40,000 people who were vaccinated in December: 23,308 people who had received just one dose, and 12,444 who had both.
Most after effects happen in the first two days after vaccination, with headache, fatigue and chills or shivers being the most common, the data revealed.
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