Effectiveness of Masking and Social Distancing During COVID-19
Masking and social distancing were highly effective interventions in reducing COVID-19 transmission, with strong evidence supporting their implementation as primary non-pharmaceutical preventive measures during the pandemic. 1, 2
Evidence for Effectiveness
Masking
- Mask use emerged as one of the most efficacious strategies to impede viral transmission, supported by a high level of evidence 1
- Healthcare workers were recommended to use appropriate respiratory protection (N95 respirators preferred, surgical masks as alternative) 2
- For the general public, masks were recommended in public settings, with cloth masks not recommended in healthcare settings when surgical masks or N95 respirators were available 1, 2
- Even moderately effective face masks played a significant role in reducing COVID-19 spread, particularly with full coverage 3
Social Distancing
- Social distancing was strongly recommended as a key non-pharmaceutical intervention 1, 2
- Maintaining at least 1-2 meters distance from others was recommended whenever possible 1, 2
- Social distancing measures included:
- Avoiding gatherings and congregations
- Using remote technology to keep in touch with friends and family
- Avoiding non-essential use of public transport
- Working from home when possible 2
Combined Effect
- The combination of mask use and social distancing was particularly powerful in preventing viral transmission 4
- Mathematical modeling demonstrated that social distancing and mask-wearing could effectively prevent COVID-19 outbreaks if adherence to both measures involved a substantial fraction of the population 4
- During the initial epidemic outbreak, with no social distancing, only 100% coverage of highly effective masks could reduce the effective reproductive number (Re) below 1 3
- During resurgence periods, with lowered transmission rates due to social distancing, masks with medium effectiveness at 80% coverage could reduce Re below 1 3
Implementation Considerations
Timing and Adherence
- Earlier implementation of control measures was shown to prevent approximately 67% of cases 2
- Measures needed to remain in place for extended periods (potentially 5+ months) 2
- Lifting measures prematurely could lead to a second peak of infection 2
- For optimal effectiveness, a substantial fraction of the population needed to adhere to both masking and social distancing measures 4
Behavioral Factors
- Messages that invoked thoughts of infecting vulnerable people or large numbers of people were found to motivate social distancing 5
- Interestingly, wearing face masks sometimes resulted in a reduction of social distancing, as masked individuals were perceived as more trustworthy 6
- This behavioral effect highlighted the importance of emphasizing continued social distancing even when wearing masks 6
Resource Allocation
- Optimized distribution of masks was important when resources were limited 7
- Prioritized coverage of the elderly improved outcomes 7
- Retaining resources for detected cases provided further mitigation under various scenarios 7
Practical Recommendations
For Healthcare Settings
- Universal safety measures included:
- Hand hygiene with alcohol-based hand rub
- Avoiding touching eyes, nose, and mouth
- Routine use of surgical masks (type II or IIR)
- Maintaining physical distance of at least one meter between staff members when mask wearing was not possible 1
- Healthcare facilities needed to implement strict screening protocols for patients, workers, and visitors 1
For the General Public
- Hand hygiene was essential, with frequent handwashing with water and soap for at least 20 seconds recommended 2
- Alcohol-based hand sanitizers were recommended when soap and water were not available 2
- Symptomatic cases were advised to remain at home for 7 days 2
- Household members of symptomatic cases were recommended to quarantine for 14 days 2
Conclusion
The evidence strongly supports that masking and social distancing were effective interventions in reducing COVID-19 transmission. These non-pharmaceutical interventions, when implemented widely and consistently, played a crucial role in mitigating the spread of the virus and reducing morbidity and mortality during the pandemic.