Objective Coronavirus disease (COVID-19) is an infectious respiratory illness caused by
the SARS-CoV-2 virus. Breathing patterns may influence the transmission of respiratory
diseases. Mouth breathing inhaled pollutants and pathogens directly into the lungs.
Therefore, this research investigated the impact of chronic mouth breathing on COVID-19
positivity in children.

Materials and Methods A total of 173 patients aged between 10 and 17 years, without any
systemic diseases or COVID-19 vaccinations, who were undergoing COVID-19 testing, were
included in the study. The age, gender, simplified oral hygiene index, and respiratory
models of the included patients were assessed. Patients with a specific malocclusion
caused by mouth breathing were diagnosed as "mouth breathers" through clinical
assessments. Those who tested positive for COVID-19 were assigned to the experimental
group, while those who tested negative were designated as the control group. The
differences in mouth breathing rates, simplified oral hygiene index, and sociodemographic
data (sex and age) between groups were statistically analysed. Subsequently, the
relationship between mouth breathing and the Delta variant was examined.

Results No statistically significant differences were found in sex, breathing pattern,
and the simplified oral hygiene index, except for age (p>0.05). The average age of the
patients in the experimental group was lower. The Delta variant was more common among
chronic mouth breathers (p<0.05).

Conclusion Chronic mouth breathing heightens the risk of transmission, as the
pathogenicity of COVID-19 viruses increases.

Clinical relevance Healthcare professionals should possess the knowledge necessary to
identify individuals who breathe through their mouths, as this group faces a heightened
risk of contracting respiratory diseases.