Data from nearly 46,000 Estonians shed light on drug side effects

A survey of nearly 46,000 Estonian gene donors has revealed how often people experience side effects from medicines and vaccines, and how those reactions can affect treatment. The study, reported by ERR, also identified a genetic variant associated with a higher frequency of vaccine side effects.

Researchers at the University of Tartu developed a questionnaire that gathered reports from nearly 46,000 donors. More than 13,000 respondents reported side effects linked to medicines, while nearly 16,000 reported reactions to vaccines. The researchers said the data form one of the largest collections of its kind and could help explain patient experiences and the causes of side effects.

About 29 percent of respondents reported side effects from medicines. Women reported them considerably more often than men. Penicillin and amoxicillin were the medicines most often named, with rashes the most common reported reaction.

About 35 percent of respondents reported vaccine-related side effects, most of them linked to COVID-19 vaccines. Study leader Lili Milani, a pharmacogenomics professor at the University of Tartu, said the findings were unsurprising because the data were collected soon after the pandemic, when many people had been vaccinated. She also noted that people who had experienced side effects may have been more likely to complete the questionnaire.

Side effects can influence whether people continue treatment, said study lead author Kristi Krebs, a pharmacogenomics researcher. Of those who described a reaction to a medicine, about half stopped the treatment altogether and a third switched to another medicine. In addition, 13 percent said they had not started treatment or had stopped it early because of side effects described in the patient information leaflet.

The large dataset also allowed researchers to examine rare and more serious reactions that can be difficult to detect in smaller studies. Milani said the identified genetic variant was associated with a higher frequency of vaccine side effects.