Characteristics of included studies
| First author (country, year) | Study design | Setting | Study period in months | Population (age range) | Number of participants | Type of hand hygiene intervention* | Duration of intervention | Number of handwashes/day | Type of infection | Calculations used for the number of handwashes/day (if applicable) | Amount of soap or alcohol used (mL or g)/person/day | Calculations used for the amount of alcohol or soap in mL or g/person/day (if applicable) | ||||
| Staff training/education | Classroom activities | Sanitiser | Soap | Combined (sanitiser and soap) | ||||||||||||
| Azor-Martinez12 (Spain, 2018) | C-RCT | CCCs | 7 | Ch (0–3 years) | 911 Ch; 24 CCC | ✓ | ✓ | ✓ | ✓ | 8 months | 7 (sanitiser) | ARI | Each child used sanitiser between 6 and 8 times/day | 10.5 mL | Assume mean 7 uses per day, 1.5 mL mean per use | |
| Biswas16 (Bangladesh, 2019) | C-RCT | Sch | 4 | Ch (5–10 years) | 10 855 Ch | ✓ | ✓ | ✓ | 10 weeks | 2.87 | Influenza | We calculated the percentage of handwashing practices by dividing the number of handwashing instances by the total number of handwashing opportunities. There were 921 handwashing opportunities in intervention group (page 5). 604 (66%) schoolchildren in the intervention group washed their hands (at end line) and 5077 students in the intervention group. 4.3 mL/person/day and assumed 1.5 mL of sanitiser use per wash gives 2.87 washes/day | 4.3 mL | N/A | ||
| Correa17 (Colombia, 2012) | C-RCT | CCC | 8 | Ch (0–5 years) | 42 CCC | ✓ | ✓ | 8 months | 5.261 | ARI and GI | We assumed that one alcohol-based hand sanitiser push=1 instance of hand wash and took into account the proportion of community and preschools, as in the calculation for mL/person/day, gives 5.261 pushes (or handwashes) per day | 3.16 mL | 32 community centres and 10 preschools included the trial, distributed among the intervention and control arms; assumed the 32 versus 10 ratio to estimate the increase in the number of pushes: 10/42 * 4.5 for preschools+32/42*5.5 for community centres=5.261 average number of pushes overall. 5.261 pushes at 1000 mL/1666 pushes=3.16 mL | |||
| Cowling19 (Hong Kong, 2008) | C-RCT | HH | 7 | A and Ch (NR) | 198 HH | ✓ | ✓ | 9 days | NR | Influenza | NR | |||||
| Cowling18 (Hong Kong, 2009) | C-RCT | HH | 8 | A and Ch (NR) | 407 HH | ✓ | ✓ | 1 week | NR | Influenza | NR | |||||
| Hubner20 (Germany, 2010) | RCT | O | 12 | A (NR) | 1230 A | ✓ | ✓ | 1 year | 3.84 | ARI and GI | 0.19 * 6 (assumed >5 handwashes means 6); 0.598 * 4 (average of 3–5); 0.205 * 1.5 (average of 1–2)+0.007 * 0 to get the mean number of handwashes per day across the whole group=3.84 | 11.52 mL | 0.19 * 6 (assume >5 handwashes means 6); 0.598 * 4 (average of 3–5); 0.205 * 1.5 (average of 1–2)+0.007 * 0 to get the mean number of handwashes per day across the whole group=3.84 mean handwashes/person * 3 mL per handwash=11.52 | |||
| Larson21 (USA, 2010) | C-RCT | HH | 20 | A and Ch (NR) | 509 HH | ✓ | ✓ | 19 months | 1.77 | ILI and influenza | 44.2% in the education group (not handwash group) reported using hand sanitiser ‘occasionally at some point during the study’ and 56.9% of these reported using hand sanitiser 1–2× in previous 24 hours’. 2.65 mL/person/day at 1.5 mL sanitiser per handwash=1.77 handwashes/day | 2.65 mL | 4.5 people/household; 30 days /month; 358 mL handwash per month gives: 2.65 mL/person/day | |||
| Lennell13 (Sweden, 2008)†, ‡ | C-RCT | CCC | 7 | Ch (mean age 3 years) | 1517 Ch; 29 CCC | ✓ | ✓ | ✓ | 30 weeks | 4 (sanitiser) | NC | N/A | 6 mL | N/A | ||
| Little22 (England, 2015) | RCT | Onl | 26 | A (≥18) | 20 066 A | ✓ | ✓ | 4 months | 7.48 | ARI | 0.04 * 1 avg+0.10 * 3.5 avg+0.22 * 5.5 avg+0.26 * 8 avg+0.38 * 10 (assuming >=10 at 10)=7.48 avg | NR | ||||
| Nicholson23 (India, 2014) | C-RCT | HH | 10 | Ch (5–18 years) | NR | ✓ | ✓ | ✓ | 41 weeks | 16 | ARI and GI | The median soap consumption was found to be 45 g per household per week in control households compared with 235 g in intervention households. 5.6 g/person/day at 0.35 g of soap per wash=16 handwashes a day | 5.60 g | 235 g/week; six people/household; gives: 5.595/person/day | ||
| Pickering14 (Kenya, 2013) | C-RCT | Sch | § | Ch (2–13 years) | 6 Sch | ✓ | ✓ | ✓ | ✓ | 8 weeks | NR | ARI and GI | NR | |||
| Ram24 (Bangladesh, 2015) | RCT | HH | 18 | A (NR) | NR | ✓ | ✓ | 10 days | 5.89 | ILI and influenza | 2.06 g soap/person/day at 0.35 g of soap per wash=5.89 washes/day | 2.06 g | Figure 3 in Ram et al24 reports median/capita soap use in grams by day of enrolment, days 2–12. Median/capita soap use in grams on last day (day 12) was 2.06 g | |||
| Roberts25 (Australia, 2000) | C-RCT | CCC | 8 | Ch (0–3 years) | 23 CCC | ✓ | ✓ | ✓ | 8 months | NR | ARI | NR | ||||
| Sandora26 (USA, 2005) | C-RCT | HH | 5 | A (NR) and Ch (6 months to 5 years) | 292 families | ✓ | 5 months | 5.2 | ARI and GI | N/A | 5.2 mL | Assumed 1 mL/hand sanitiser use (may not be correct as it is one pump but could have done >1 pump of sanitiser each handwash), 5.2 uses/day/person | ||||
| Savolainen-Kopra15 (Finland, 2012)§,‡ | C-RCT | O | 18 | A | 683 A; 21 office work units; six corporations | ✓ | ✓ | ✓ | 15–16 months | 6.1 (soap) and 6.9 (sanitiser) | ARI and GI | N/A | NR | |||
| Simmerman27 (Thailand, 2011) | C-RCT | HH | 16 | A and Ch (NR) | 442 Ch; 1147 household members | ✓ | ✓ | 3 weeks | 4.7 | Influenza | N/A | 7.71 mL | 54 mL/person/week=7.714 mL/person/day | |||
| Stebbins28 (USA, 2011) | C-RCT | Sch | 14 | Ch (NR) | 3360 Ch; 10 Sch | ✓ | ✓ | 1 influenza season | 2.4 | Influenza | N/A | 1.44 mL | 0.6 mL per use*2.4 times per day=1.44 | |||
| Zomer29 (Netherlands, 2015) | C-RCT | CCC | 7 | Ch (6 months to 3.5 years) | 545 Ch; 71 CCC | ✓ | ✓ | 6 months | NR | ARI and GI | NR | |||||
*Only hand hygiene arms of the included studies.
†This study was not included in the dose–response analysis as the infection was reported for any infection (not specific to respiratory infections).
‡Studies not included in the meta-analysis.
§Bathrooms at the workplaces were equipped with liquid hand soap (all arms).
A, adults; ARI, acute respiratory infections; avg, average; CCC, childcare centres; Ch, children; C-RCT, cluster randomised controlled trial; GI, gastrointestinal infections; HH, households; ILI, influenza-like illness; N/A, not applicable; NC, not clear; NR, not reported; O, offices; Onl, online; RCT, randomised controlled trial; Sch, schools.