[Using face masks outdoor: beginning a debate to rediscuss current policies]

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Clinical Trials

Background:

• International recommendations for face mask usage evolved significantly during the COVID-19 pandemic, shifting from symptomatic individuals to widespread outdoor mandates in some regions.
• Italy's mask mandates progressed from closed public spaces to national requirements, including outdoor settings.
• The evolving policies necessitate a critical evaluation of the scientific evidence supporting face mask effectiveness and safety.

Purpose of the Study:

• To critically analyze randomized controlled trials (RCTs) assessing the effectiveness of medical face masks in preventing respiratory infections in community and outdoor settings.
• To evaluate the evidence base for World Health Organization (WHO) recommendations versus more stringent face mask policies.
• To discuss potential adverse effects of prolonged face mask use, particularly outdoors, and compare mask impacts during SARS and COVID-19.

Main Methods:

• Critical analysis of existing randomized controlled trials (RCTs) on face mask effectiveness.
• Evidence-based reasoning to address questions regarding mask efficacy and policy.
• Discussion of potential adverse effects and comparative analysis between SARS and COVID-19 mask impacts.

Main Results:

• The evidence supporting stringent face mask policies, especially for outdoor use, may be weaker than perceived.
• Prolonged and continuous use of face masks, particularly outdoors and during physical activity, may have underestimated adverse effects.
• Differences exist in the potential impact of face masks between SARS and COVID-19.

Conclusions:

• Further pragmatic RCTs are needed to conclusively determine the net balance of benefits versus harms of prolonged face mask use, especially outdoors.
• Policies regarding face mask usage should consider the available evidence, avoiding continuous or prolonged use without clear necessity.
• A cautious approach is recommended, weighing potential benefits against possible adverse effects of face masks in various settings.