Homemade face masks likely need at least two layers to curb Covid-19 spread, according to a new study published in the British Medical Journal. It found preferably three layers of cloth were needed to reduce dispersal of viral droplets from nose and mouth. A team of Australian researchers compared the effectiveness of single and double-layer cloth face coverings, with a 3-ply surgical face mask at reducing droplet spread. They found the surgical face mask was the most effective, followed by a double-layer covering. They also noted that other factors contributed to the effectiveness of cloth face masks, such as the material, fit and washing.