Table 3 Characteristics of the study investigating the influence of rubbing friction

Tan et al

(2020) [26]

Switzerland

Within-subject RCT

Laboratory

19 HCWs

1) Poured ABHR + rubbing;

2) Sprayed ABHR + rubbing;

3) Sprayed ABHR without rubbing

Bacterial load on hands

Fingertips

Product ABHR isopropanol 60% (v/v)

Application time 30 s

ABHR volume 3 ml

Application technique 6-step (for intervention 1 & 2); sprayed ABHR without hand rubbing (for intervention 3)

Artificial contamination (E. coli)

Mean log₁₀ reduction (95% CI)

Poured ABHR + rubbing: 3.46 (1.27–5.65);

sprayed ABHR + rubbing: 3.66 (1.68–5.64);

sprayed ABHR without rubbing: 2.76 (1.65–3.87)

Sprayed ABHR without hand rubbing resulted in significantly lower bacterial load reduction than poured or sprayed ABHR with hand rubbing (− 0.70; 95% CI: − 1.13 to − 0.28)