Masks work best when everyone wears them, but not at the time when someone puts it on incorrectly.

For those who wear the face incorrectly, their risk of getting infected by the rogue virus is 2.5 times higher than those who wear it properly.

These findings came out in a survey conducted by IEDCR which says the rate of infection is cent percent among the people who never use masks outside the home.

Institute of Epidemiology Disease Control and Research (IEDCR) conducted a surgery from April 1 to April 20 among 148 Covid-19 positive patients and 245 Covid-19 negative people.

Data was collected from both the groups and then analysed the reason for infection and found that mask is the key way to protect from infection.

The study said to reduce the transmission of Covid-19 completely, people will have to wear face masks and follow other health guidelines.

Contacted, Sayedur Rahman, chairman of the pharmacology department at BSMMU, told The Daily Star that mask is the key to cut the transmission and it is an established fact.

"The government will withdraw lockdown but one thing has to be ensured that the people wear mask properly. If the people of an area avoid wearing masks, that area should be put under lockdown," he said.

Prof Rahman also said masks will cut the transmission while vaccines will reduce the death.

The government has already introduced a "no mask no service" policy to cut the transmission.

World Health Organization has repeatedly said that even after vaccination, people have to wear a mask.

Recently, United States Centers for Disease Control and Prevention (CDC) has found that double masking, with cloth and surgical masks, can prevent leakage of air and fit the contours of the face better.