Characteristics of all 41 randomised trials on non-pharmaceutical interventions to prevent COVID-19 as of August 2021
| Trial ID | Start to end date | Country | Intervention topic | N individuals (clusters*) | Description (population, intervention and comparison, and outcomes related to SARS-CoV-2 infections) Results (we report information on published results for primary outcomes related to SARS-CoV-2 infections where available, and for secondary outcomes only where the primary outcome was not related to SARS-CoV-2 infections; of note, outcomes reported in published results might differ from the registry information) |
| Completed (n=12) | |||||
| Completed with published results (n=9) | |||||
| ChiCTR2000030317 | 2020–02 to 2020–04 | China | Masks | 320 | Fully closed negative-pressure gastroscope isolation mask vs no mask for patients (18–79 years) during hospital-based gastroscopy on COVID-19 cases (secondary outcome). Results: No COVID-19 cases were recorded during follow-up. |
| NCT04337541 | 2020–04 to 2020–06 | Denmark | Masks | 6024 | Surgical face mask recommendation vs no such recommendation in community-living adults (≥18 years) on confirmed and/or diagnosed SARS-CoV-2 infection and/or COVID-19 (combined primary outcome), confirmed SARS-CoV-2 infections (secondary outcome), and self-reported symptoms of COVID-19, healthcare confirmed or diagnosed SARS-CoV-2 infections, and mortality associated with COVID-19 (tertiary outcomes). Results: No statistically significant differences in SARS-CoV-2 infections/COVID-19 (OR, 0.82 (95% CI 0.54 to 1.23)) |
| NCT04406909† | 2020–05 to 2020–06 | Norway | Fitness centre | 3764 | Access to indoor fitness centres applying physical distancing and enhanced hand and surface hygiene vs no access for community-living adults (18–64 years) on confirmed SARS-CoV-2 infections or hospital admissions for COVID-19 (co-primary outcomes), individuals with COVID-19 antibodies, need of ventilator treatment after hospital admissions for COVID-19, intensive care unit admissions for COVID-19, cause-specific mortality and confirmed SARS-CoV-2 infections in employees at training centres (secondary outcomes). Results: No transmission of SARS-CoV-2 at training facilities (only one participant allocated to the intervention tested positive but did not use the training facilities). No outpatient visits or hospital admissions due to COVID-19 in either group. None of the employees were tested positive. |
| CTRI/2020/07/026667† | 2020–09 to 2020–11 | India | Yoga | 280 | Morning and evening Pranayama yoga sessions vs general fitness practices (eg, walking, jogging, running) for hospital-based healthcare professionals (18–65 years) with COVID-19 duties on confirmed SARS-CoV-2 infections (primary outcome) and its severity (secondary outcome). Results: Statistically significant difference of SARS-CoV-2 infections between the intervention and control group favouring yoga sessions (1 vs 9 participants, p=0.01). |
| NCT04644328‡ | 2020–11 to 2021–01 | USA | Facebook ads | 11 954 109; 23 302 290 (820; 767) | Facebook ads for community-living adults (≥18 years) containing a short video on the importance of staying safe during Thanksgiving and Christmas by considering not travelling, social distancing, and using a mask when appropriate vs no Facebook ads on confirmed SARS-CoV-2 infections (analysis on a zip-code level) (secondary outcome). Results: Statistically significant differences of SARS-CoV-2 infections between the intervention and control group (zip-code area) favouring the Facebook ads (recorded infections declined by 3.5% (adjusted 95% CI −6.2% to −0.7%)). |
| NCT04630054† | 2020–11 to 2021–04 | Bangladesh | Masks and behaviour change | 342 126 (600) | Community-level masks promotion strategies (multiple levels of randomisation, including free surgical or cloth face masks with information on the importance of masking, role modelling by community leaders and imams, and in-person reminders) for community-living adults (≥18 years) vs no intervention on confirmed symptomatic SARS-CoV-2 infections (primary outcome) and self-reported symptoms of COVID-19 (secondary outcome). Results: Statistically significant difference of symptomatic SARS-CoV-2 infections favouring mask use promotion (overall: adjusted prevalence ratio 0.91(95% CI 0.82 to 1.00)). Statistically significant difference for surgical masks (adjusted prevalence ratio 0.89 (95% CI 0.78 to 1.00)) but no statistically significant reduction with cloth face masks (adjusted prevalence ratio 0.95(95% CI 0.79 to 1.11)). |
| NCT04668625 | 2020–12 to 2020–12 | Spain | Mass event | 1047 | Access to an indoor music event with systematic same-day screening of attendees with antigen-detecting rapid diagnostic tests, use of face masks, and adequate air ventilation vs no access for community-living adults (18–59 years) on confirmed SARS-CoV-2 infections (primary outcome) and self-reported symptoms of COVID-19 (secondary outcome). Results: No SARS-CoV-2 infections in the intervention group and two infections in the control group were reported (reported incidence difference, estimated using a Bayesian approach –0.15% (95% CI –0.72 to 0.44)). |
| ISRCTN18100261 | 2021–04 to 2021–06 | UK | Testing strategy | 238 579 (201) | Daily testing of contact cases vs isolating contact cases of school staff and students (secondary school and further education college) on COVID-19-related absences from school among those otherwise eligible to be in school and confirmed symptomatic SARS-CoV-2 infections (co-primary outcomes) and confirmed SARS-CoV-2 infections in contact cases (secondary outcome). Results: The adjusted incidence rate ratio for symptomatic SARS-CoV-2 infections was 0.96 (95% CI 0.75 to 1.22) and for COVID-19-related absences 0.80 (95% CI 0.53 to 1.21). |
| NCT04872075† | 2021–05 to 2021–06 | France | Mass event | 6678 | Access to an indoor music event with systematic antigen-screening within 3 days, medical mask-wearing and optimised ventilation vs no access for community-living adults (18–45 years) on confirmed SARS-CoV-2 infections (primary outcome). Results: The estimated absolute difference between attendees and non-attendees for SARS-CoV-2 infections had a 95% CI –0.26% to +0.28% which did not exceed the prespecified, non-inferiority margin (0.35%). |
| Completed without published results (n=3) | |||||
| ISRCTN14602359 | 2020–03 to 2021–03 | UK | Behaviour change | n.r. (6899) | Behaviour intervention on how to reduce the spread of infections using Germ Defence (interactive website helping users with preplanning about effective isolation of an infected household member, personalised goal setting for increasing a range of infection control behaviours, changing the home environment to support new habits, and problem-solving to overcome barriers) promoted by general practitioners to their adult patients (≥18 years) vs no intervention on COVID-19 diagnoses, COVID-19 symptoms presentation, primary care consultations, hospital admissions (secondary outcomes). |
| NCT04620798 | 2020–09 to 2020–12 | USA | Behaviour change | 1700 | Immediate vs delayed provision of COVID-19 antibody test results in addition to assessment of engagement with COVID-19 prevention behaviours following testing of university students (≥18 years) on confirmed SARS-CoV-2 infections (secondary outcome). |
| NCT04647305 | 2021–01 to 2021–03 | Colombia | Masks and behaviour change | 233 | Closed face shield, surgical face mask, and an educational video intervention vs surgical face mask alone and an educational video intervention for community-living adults (≥18 years) on confirmed SARS-CoV-2 infections (primary and secondary outcome). |
| Ongoing (n=17) | |||||
| NCT04359264 | 2020–04 to 2020–05 | Canada | Income support | 392 | Income support of US$1000 to community-living adults (≥18 years) suffering from COVID-19-related financial disruptions vs no income support on self-reported symptoms consistent with COVID-19 (primary outcome) and confirmed SARS-CoV-2 infections (secondary outcome). |
| NCT04296643 | 2020–04 to 2021–04 | Canada, Israel | Masks | 576 | Surgical masks vs N95 respirator worn when providing care to patient with febrile respiratory illness for hospital-based nurses (≥18 years) on confirmed SARS-CoV-2 infections (primary outcome) and COVID-like symptoms, absenteeism from work, pneumonia, intensive care unit admissions, mechanical ventilations, and mortality (secondary outcomes). |
| NCT04321928 | 2020–04 to 2021–08 | Hungary | Behaviour change | 7576 | Health education regarding lifestyle changes (questioning and recommendations in mental health, smoking habits, physical activity, dietary habits, and alcohol consumption) in addition to personalised vs general health education aiming towards improvement of these factors with general recommendations following the WHO principles for community-living adults (≥60 years) on intensive care unit admissions, hospital admissions, and mortality in participants with confirmed SARS-CoV-2 infections (combined primary outcome) and general practitioner visits, emergency, hospital and intensive care admissions, length of hospitalisations and intensive care unit stay and organ dysfunction (secondary outcomes). |
| NCT04464486 | 2020–04 to 2022–03 | USA | Symptom tracking | 300 | COVID-19 and cancer-related symptom tracking, automated self-management support messages for symptoms reported, and a nurse practitioner monitoring and responding to alerts for COVID-19 symptoms and poorly controlled or worsening cancer symptoms vs information by research staff reviewing COVID-19 symptoms, home precautions, and instructions on what to do to address concerns that arise in adult cancer outpatients (≥18 years) on self-reported COVID-19 symptoms (secondary outcome). |
| NCT04471766 | 2020–07 to 2021–08 | Guinea-Bissau | Masks | 40 000 | Certified cloth face masks plus information on COVID-19 prevention vs information alone for community-living children and adults (≥10 years) on self-reported COVID-like illnesses, consultations for COVID-19 like illness or/and confirmed SARS-CoV-2 infections, self-reported COVID-19 like illnesses plus hospitalisations or mortality, and all-cause mortality (co-primary outcomes). |
| ISRCTN69564614 | 2020–08 to 2022–01 | UK | Special housing | 1200 | Settled housing temporarily accommodated by the local authority vs business-as-usual accommodation provided by local authorities for community-living homeless individuals (no details concerning age) on self-reported SARS-CoV-2 infections (primary outcome). |
| NCT04753645 | 2020–09 to 2021–05 | Bangladesh | Behaviour change | 3840 (194) | Multicomponent hygiene intervention (handwashing stations, in-person demonstration, hygiene meetings) and soap distribution vs multicomponent hygiene intervention without no soap distribution vs soap distribution without multicomponent hygiene intervention vs no intervention for community-living children and adults (≥10 years) on self-reported symptoms of transmissible diseases (no details if limited to COVID-19; co-primary outcome). |
| PACTR202102616421588 | 2020–11 to 2021–07 | Congo | Behaviour change | 1312 (121) | Multicomponent hygiene intervention (construction of water points, latrines and improved access to water and sanitation) for community-living children and adults (with no restriction on age) vs no intervention on self-reported COVID-19-like illnesses (co-primary outcome). |
| NCT04565509 | 2020–11 to 2022–09 | USA | Behaviour change | 2500 (6) | General vs targeted messaging on COVID-19 and the importance of testing to students, families and school staff (5–90 years) on confirmed SARS-CoV-2 infections (phase 1; secondary outcome). In phase 2, an adapted messaging strategy based on phase one and its implementation barriers and facilitators will be tested. |
| NCT04499391 | 2020–12 to 2022–07 | USA | Information and education | 24 560 (200) | Multiple real-time, interactive videoconferencing information courses on COVID-19-related guideline implementation with refresher course vs multiple information courses alone for nursing home staff (≥18 years) on SARS-CoV-2 infections (no details if confirmed, diagnosed, or self-reported infections; primary outcome) and COVID-19 hospitalisations, mortality due to COVID-19 and influenza-like illnesses (secondary outcomes). |
| NCT04726371 | 2021–01 to 2022–10 | USA | Information and education | 5350 (400) | Tailored vs generic education and information on guidelines for COVID-19 mitigation for congregate care home staff and residents (≥18 years) on confirmed SARS-CoV-2 infections (co-primary outcome). |
| NCT04591015 | 2021–02 to 2021–08 | USA | Information and education | 172 | COVID-19 support messages that provide information addressing identified barriers in Hispanic underserved communities (eg, obtaining testing supplies and medications, accessing routine medical care and completing other important diabetes self-management behaviours such as healthful eating, exercise, social distancing, quarantine, and stay-at-home/lockdown guidelines) for outpatients with diabetes (≥18 years) vs usual intervention on self-reported COVID-19 diagnoses (secondary outcome) and any hospital readmissions (tertiary outcome). |
| NCT04830761 | 2021–03 to 2022–04 | Switzerland | Behaviour change | 710 | Combination of diverse hygiene behaviour change strategies (habit, motivation, social norms) for community-living adults (≥18 years) on self-reported influenza-like infection symptoms and self-report of confirmed SARS-CoV-2 infections (secondary outcomes). |
| NCT04765475 | 2021–03 to 2022–09 | USA | Behaviour change | 600 | Motivational interviewing (preventive behaviours and COVID-19 testing when experiencing symptoms, and isolation and care-seeking when positively tested) and supportive services (provision of supportive services such as referrals to needed medical, mental or behavioural healthcare and delivery of a hygiene kit containing basic hygiene supplies; participants will also be provided information on COVID-19 and nearby testing locations, mask wearing, how to prevent the spread in the home, and managing stress during COVID-19) vs COVID-19 symptom monitoring system (alerts and information to request home testing after first symptoms) and supportive services vs motivational interviewing, COVID-19 symptom monitoring system, and supportive services vs supportive services alone community-living for young adults (18–34 years) and older adults (≥65 years) on confirmed SARS-CoV-2 infections (co-primary outcome). |
| NCT04875520 | 2021–05 to 2023–03 | USA | Testing strategy | 10 000 (16) | Weekly testing and symptomatic testing for SARS-CoV-2 vs symptomatic testing alone of students and school staff (≥4 years) on confirmed SARS-CoV-2 infections (primary outcome). |
| NCT04832919 | 2021–07 to 2022–05 | USA | Behaviour change and testing strategy | 810 (270) | Information on the importance of infection control measures, developing, implementing and follow-up an infection control plan tailored to the unique circumstances of the household, training on infection control skills necessary for optimal implementation of the plan, and offering of tests during home visits by nurses vs standard access to COVID-19 testing sites and standard COVID-19 public health messaging to community-living households (≥10 years) on self-report of COVID-19 symptoms or diagnoses (co-primary and secondary outcome). |
| ACTRN12621000567820 | 2021–08 to 2022–10 | Australia | Air-sterilisation strategy | 400 (10) | Air-sterilisation strategy using commercially available upper-room germicidal ultraviolet light in nursing homes vs no intervention on confirmed respiratory infections including SARS-CoV-2 (primary outcome) and hospitalisations (secondary outcome). |
| Not yet recruiting (n=9) | |||||
| NCT04453553 | 2020–07 to 2020–09 | UK | Testing strategy | n.r. (50) | Screening for COVID-19 via nasopharyngeal swab taken at day 0 and 14, with the addition of daily nasal swabs tested via rapid test system vs screening for COVID-19 via nasopharyngeal swab taken at day 0 and 14 alone of nursing home residents (without age limit) on confirmed SARS-CoV-2 infections (primary outcome) and suspected or confirmed SARS-CoV-2 infections, COVID-19-related hospitalisations and mortality of residents, staff, and visitors (secondary outcomes). |
| PACTR202008485004797 | 2020–08 to 2021–03 | South Africa | Information and protective equipment | 720 | Printed information material (transmission and COVID-19 caring at home), daily information delivered via Whatsapp, protective equipment (masks, hand sanitiser, bleach, gloves), and lay healthcare worker support vs printed information and on demand hotline service for community-living household contacts (≥12 years) of persons diagnosed with SARS-CoV-2 on confirmed SARS-CoV-2 infections of household contacts (primary and secondary outcome). |
| CTRI/2020/07/026796 | 2020–08 to n.r. | India | Masks | 10 000 (45) | Cotton face masks vs no intervention for community-living adults (≥18 years) on confirmed SARS-CoV-2 infections (primary and secondary outcome). |
| CTRI/2020/12/029805 | 2020–12 to n.r. | India | Goggles | 30 | Ventilated goggles vs standard goggles for healthcare workers inside COVID-19 intensive care unit (18–50 years) on confirmed SARS-CoV-2 infections (secondary outcome). |
| NCT04756609 | 2021–02 to 2021–06 | France | Testing strategy | 104 000 (18) | Systematic offer of nurse-driven SARS-CoV-2 screening following a self-administered questionnaire about COVID-19 symptoms, possibilities of close contacts, risk exposure situations and sociodemographic characteristics combined with usual emergency department practice with physician-directed diagnostic testing vs usual emergency department practice alone for adults (≥18 years) in the emergency department on confirmed SARS-CoV-2 infections (primary and secondary outcome) and description of the symptomatology (secondary outcome). |
| NCT04823351 | 2021–04 to 2021–11 | Switzerland | Masks | 1200 (n.r.) | FFP2 masks vs surgical masks for nurses (≥18 years) working in nursing homes on confirmed SARS-CoV-2 infections (primary outcome). |
| NCT04898127 | 2021–05 to 2021–12 | Norway | Mass event | 30 000 | Rapid test before access to a concert vs no access for community-living adults (18–45 years) on confirmed SARS-CoV-2 infections (primary outcome) and diagnosed SARS-CoV-2 infections and hospital admissions (secondary outcomes). |
| NCT04868942 | 2021–05 to 2022–05 | France | Mass event | 4500 | Access to an indoor concert respecting protective measures (individual protection kit with (1) disposable FFP2 masks, hydroalcoholic solution, disposable tissues, garbage bag, and water bottle, (2) health mediation with information on barrier measures, (3) physical distancing and sitting participation and (4) person flow management vs no access for community-living students (18–29 years) on confirmed SARS-CoV-2 infections (primary and secondary outcome). |
| NCT04979858 | 2021–08 to 2022–02 | USA | Masks | 200 | Newly developed reusable form-fitting fabric focal masks vs own masks and masking practices for students (≥18 years) living on the university campus on SARS-CoV-2 infections (no details if confirmed, diagnosed, or self-reported infections; primary outcome). |
| Withdrawn or terminated early (n=3) | |||||
| ISRCTN44152751 (w) | 2020–03 to 2020–09 | Norway | School opening | 238 125 (1905)§ | School opening vs school closing for 5–10 level pupils on confirmed SARS-CoV-2 infections of household contacts (primary outcome) and confirmed SARS-CoV-2 infections, and hospitalisation or mortality of grandparents and great grandparents (secondary outcomes). |
| NCT04377165 (t) | 2020–05 to 2020–08 | Australia | Information and education | 9000 (n.r.) | Newsfeed on reliable accurate information on the COVID-19 pandemic with gamification function and reward system (links to resources for infection control, watching or completing tasks, and playing games to earn points) vs newsfeed alone for healthcare workers in nursing homes (≥18 years) on SARS-CoV-2 infections in the facility (no details if confirmed, diagnosed, or self-reported infections; secondary outcome). |
| NCT04896970 (w) | 2021–06 to 2021–07 | France | Mass event | 1390 | Access to an indoor concert vs no access respecting safety measures (masks, hydroalcoholic gel) for community-living adults (18–59 years) on confirmed SARS-CoV-2 infections (primary outcome). |
*For cluster randomised trials only.
†Published as preprint results as of 14 November 2021.
‡Intervention was done twice (first on Thanksgiving, second on Christmas), numbers separated by semicolon for the first and second trial part.
§Planned sample size was calculated by the mean of the reported minimum and maximum for number of participants (116 750–359 500) and clusters (934 and 2876).
GP, General practitioner; n.r., not reported; t, Terminated early (due to 'engagement issues, poor recruitment to study'); w, Withdrawn (trial did and will never start: no reasons provided in the registry (ISRCTN44152751), abandonment (NCT04896970)).