Low prevalence of asthma in Mexican children and adults with a positive rtRT-PCR test for SARS-CoV-2: a cross-sectional study during the 2020 pandemic.

BACKGROUND

It has recently been argued that asthma does not increase the risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. If so, the prevalence of asthma in subjects diagnosed with COVID-19 should be lower than in the general population.

OBJECTIVE

To determine the prevalence of asthma in Mexican children and adults with SARS-CoV-2 infection.

METHODS

A public database of the Epidemiological Surveillance System for Viral Respiratory Disease in Mexico was analyzed. Those who underwent the real-time reverse transcriptase-polymerase chain reaction-SARS-CoV-2 (rtRT-PCR-SARS-CoV-2) test from February 27 to June 21, 2020, were included. In addition to the prevalence of asthma, some factors associated with it were investigated.

RESULTS

Data from 417,366 subjects were analyzed. Asthma prevalence in children, adults, and global were 3.7%, 3.3%, and 3.3%, respectively. Although the asthma prevalence was lower in SARS-CoV-2 positive over negative patients, significant differences were only found in adults (2.8% vs. 3.7% respectively; odds ratio (OR) = 0.74; 95% confidence interval (CI): 0.71-0.77); but not in children (3.5% vs. 3.8%, respectively; OR = 0.91; 95%CI: 0.76-1.10). Multivariate analysis showed in younger than 18 years that girls and immunosuppression were factors associated with a decrease in the odds to develop asthma. In adults, asthma was positively associated with females, obesity, smoking, immunosuppression, chronic obstructive pulmonary disease, arterial hypertension, and cardiovascular disease.

CONCLUSION

The prevalence of asthma in child and adult were lower than those previously reported. Our study seems to support the hypothesis that asthma patients have a lower risk of SARS-CoV-2 infection. Further studies are required to demonstrate the consistency of our findings.