Sir Patrick Vallance taking questions during Downing Street Coronavirus briefing

The video discusses how science adapts to new evidence, particularly in the context of mask usage and COVID-19. It highlights the WHO's current recommendations on masks, emphasizing that masks are more effective in preventing transmission to others rather than protecting oneself. The video also addresses the issue of asymptomatic transmission and how it has influenced policy changes in some countries. An ongoing review of mask evidence is mentioned, with a commitment to update recommendations if new evidence suggests a change is needed.

What factors are considered when evaluating the effectiveness of masks?

What would happen if the review of mask evidence concludes a change is necessary?