Aim: Infections in early childhood are common reasons to seek medical attention. This study compares the prevalence of infections, and the use of antibiotics and antipyretic–analgesics, in children from Finland, Estonia and Russian Karelia.

Methods: Children with a genetically increased risk for type 1 diabetes (N = 797) were observed from birth up to 3 years of age. Illnesses and medications were reported by parents continuously. All reported infections, antibiotics and antipyretic–analgesics were compared between Finland and Estonia, and to a lesser extent with Russian Karelia, due to poor study compliance.

Results: Compared with Estonians, Finns reported more infections during the first and second years of life. During the follow‐up, Finnish children had 10 infections while Estonians only had 8 (p < 0.001). Finns also used more antibiotics and antipyretic–analgesics in each year during the follow‐up. Russian Karelians reported the lowest frequency of infections and the most infrequent use of antibiotics and antipyretic–analgesics in the first two years of life.

Conclusion: Infections and the use of antibiotics and antipyretic–analgesics in early childhood were most frequent in Finland, where socio‐economic conditions are the most developed and microbial encounters are sparse. This may reflect on the hygiene hypothesis, a less effective immune system that allows normally harmless microbes to attack and cause clinical infections.