Phipatanakul W, Koutrakis P, Coull BA, et al. - The use of a school-wide integrated pest management (IPM) programme or classroom high-efficiency particulate air (HEPA) filter purifiers did not significantly reduce symptom-days with asthma in children with active asthma. However, when interpreting the study findings, allergen levels, particle exposures, and asthma symptoms at baseline may need to be taken into account.

• The trial was completed by all 236 students who were randomized (mean age, 8.1 [SD, 2.0] years; 113 [48%] female).

• At baseline, the 2-week mean symptom-days with asthma were 2.2 (SD, 3.9), and 98% of the classrooms had detectable levels of mouse allergen.

• Because there was no statistically significant difference between the two interventions, the results were pooled.

• During a 2-week period, the mean was 1.5 symptom-days with asthma after using the school-wide IPM programme vs 1.9 symptom-days without IPM across the school year, which was not statistically significant.

• During a 2-week period, the mean was 1.6 symptom-days with asthma after using HEPA filter purifiers in classrooms vs 1.8 symptom-days after using sham HEPA filter purifiers across the school year, which was not statistically significant.

• There were no adverse events associated with the intervention.