Following the COVID-19 pandemic, policies such as social distancing, hand washing, and the use of masks were implemented, which could play an important role in the reduction of infectious diseases. An observational, descriptive, cross-sectional study was conducted to observe the prevalence of respiratory infections in children under 15 years of age during the 2018–2020 period in Primary Care centres in Central Catalonia. In 2020, there was a 44.3% decrease in total consultations for respiratory infections compared to 2019. All respiratory infections exhibited a significant decrease except flu-like syndrome; children between the ages of 6 and 12 had the highest prevalence of flu-like syndrome (87.6%), and the SARS-CoV-2-19 infection was most frequent (4%) among those between the ages of 12 and 15. Compared to urban centres, rural centres presented a higher prevalence of all infections except flu-like syndrome and SARS-CoV-2. In conclusion, the COVID-19 pandemic caused a significant decrease in the number of consultations for respiratory infections in the paediatric population, except for flu-like syndrome, which increased in cases in January, February, and March 2020. No differences were found between sexes, although differences were found in the distribution of the different age groups.