KARACHI: Findings of an international study have revealed that a person infected with COVID-19 can pass on the contagion to a healthy person in 15 minutes if both are unmasked. The study shows that a cloth mask offers the weakest protection while an N-95 mask presents the most effective protection against the SARS-CoV-2 or the Coronavirus.
“Data shows that if two persons are without masks and one of them is infected, then the infection will spread in 15 minutes. If the second person wears a cloth mask, then the virus will take 20 minutes,” says the study conducted by the American Conference of Governmental Industrial Hygienists (ACGIH).
The Center for Disease Control and Prevention (CDC) of the United States says the Omicron variant can spread more easily than the original SARS-CoV-2 virus. How easily the Omicron variant spreads compared to the Delta variant remains unknown. The CDC expects that anyone with the Omicron infection can spread the virus to others, even if they are vaccinated or don’t show any symptoms.
The effectiveness of various types of masks has become the subject of discussion as the high level of infectiousness of the Omicron variant has once again highlighted the need for an effective first shield of defence. According to recent observations made by scientists and experts, cloth masks may not provide enough protection against the virus.
Experts at the American Conference of Governmental Industrial Hygienists believe that N-95 masks offer maximum protection against the transmission of the virus.
“In case of N-95 respirator or mask, it takes at least 2.5 hours to transmit the infection from one person to another person, if the infected person is not wearing a mask. If both are wearing N95 masks, then the virus will take 25 hours to transmit,” the ACGIH study says.
The study shows that surgical masks offer better protection than cloth masks, though data reveals that if the infected person is not wearing a mask and the second person is wearing a surgical mask, then the infection can transmit in 30 minutes.
While many people choose cloth masks over N95 for comfort, experts recommend pairing cloth masks with surgical models. Large droplets can be blocked by one layer of cloth masks but small aerosols are not. A cloth mask or a surgical mask do not make much difference if the variant is highly transmissible.
Omicron is the most contagious variant of SARs-CoV-2 so far. People with two and three doses of the vaccines are also getting infected. Masks have become an essential first line of defence in this regard.
Data shows that if both the infected and non-infected persons are wearing cloth masks, the infection will spread in 27 minutes. Surgical masks provide up to 30 minutes of protection from infection if an infected person is wearing the mask while the other is unmasked; if both are wearing surgical masks, then there is one hour of protection. If one is wearing the N-95 mask and the other a surgical mask, the spread of the infection can be contained for up to 5 hours.
CDC recommendations regarding masks The CDC recommends that masks should have two or more layers of washable, breathable fabric. They should completely cover the nose and mouth, fit snugly against the sides of the face and don’t have gaps. They should also have nose wires to prevent air from leaking out of the top of the mask.
Masks that are not recommended are those which are made of fabric that makes it hard to breathe, for example, vinyl, have exhalation valves or vents which allow virus particles to escape.
Similarly, masks that are specially labelled “surgical” N-95 respirators should not be used by common people as those should be prioritised for healthcare personnel, the CDC recommends.