Wearing a cloth mask over a surgical mask could reduce the wearer's exposure to Covid-19 by more than 90 per cent, according to a study conducted by the U.S. Centers of Disease Control and Prevention (CDC).

The study, which was conducted in January 2021, also recommended knotting the ear loops of a surgical mask, and then tucking the excess material close to the face, in order to increase protection against Covid-19.

According to the study, until a "vaccine-induced population immunity" is achieved, universal masking remains a highly effective means to slow the spread of Covid-19, when combined with other protective measures, such as physical distancing, avoiding crowds and poorly ventilated indoor spaces, and good hand hygiene.

It helps to wear your mask more snugly

The CDC conducted various experiments to assess the methods that will improve the efficacy of masks.

One of the experiments assessed how effective various mask combinations were in reducing the amount of particles emitted during a cough.

Ten mask combinations, using various configurations of no mask, double masks, and unknotted or knotted and tucked surgical masks were assessed.

Results from this experiment demonstrated that the unknotted surgical mask alone blocked 56.1 per cent of particles emitted from a simulated cough, while the cloth mask alone blocked 51.4 per cent.

The combination of the cloth mask covering the surgical mask, or simply wearing two masks, blocked 85.4 per cent of the cough particles, while the knotted and tucked surgical mask blocked 77 per cent.

The study also showed that the best protection from Covid-19 can be had when both the source of the cough particles and the receiver of the particles were both fitted with either double masks or knotted and tucked masks, as the exposure of cough particles was reduced by 96.4 per cent and 95.9 per cent respectively.

Only 35 out of 50 U.S. states currently require people to wear masks in public

According to the CDC, masks are currently required on planes, buses, trains and other forms of public transportation travelling into, within or out of the U.S., and in U.S. transportation hubs such as airports and stations.

However, regulations involving wearing masks in other public settings differ between the various states.

As of Feb. 12, 2020, 35 state governments require people to wear face coverings in public to curb the spread of Covid-19.

In addition, the District of Columbia and Puerto Rico also have mask orders in place.

However, four states which previously had mask mandates covering the general public have lifted them, including Montana, Iowa, North Dakota and Mississippi.

States that do not require the wearing of masks in public include Alaska, Florida, Iowa, South Dakota, among others.

Top image via CGTN Global Business/YouTube.