Coronavirus: Controversial Danish study shouldn't stop people wearing masks, author says

A Danish study published this week found face coverings provided only limited protection against COVID-19 to the wearer - but experts say that isn't a reason not to wear them.

The research, released this week in the Annals of Internal Medicine journal, concluded that wearing surgical masks didn't "reduce the SARS-CoV-2 infection rate among wearers by more than 50 percent in a community with modest infection rates, some degree of social distancing, and uncommon general mask use". It said that this data was "compatible with lesser degrees of self-protection".

However, the study didn't analyse the effectiveness of masks in limiting transmission from an infected wearer to another individual. It also had other limitations, such as the research taking place early on in the pandemic when COVID-19 spread was lower and the researchers not ensuring people properly wore their masks.

Many experts have pointed out that the study shouldn't convince people to stop wearing masks.

Forbes reports that even the study's lead author, Dr Henning Bundgaard, says that "a small degree of protection is worth using the face masks".

Dr Christine Laine, the journal's editor-in-chief, said the study "did not answer the question about whether widespread masking mitigates SARS-CoV-2 infection". It wasn't focused on whether masks could protest wearers from COVID-19 in areas with high infection rates or a lack of other preventative measures.

Top international health agencies also continue to recommend masking up for people to protect both themselves and others. 

The World Health Organization (WHO) advises that "masks reduce potential exposure risk from an infected person whether they have symptoms or not".

"People wearing masks are protected from getting infected. Masks also prevent onward transmission when worn by a person who is infected."

The United States' Center for Disease Control and Prevention last week also said that masks are beneficials for those around wearers.

"Masks are primarily intended to reduce the emission of virus-laden droplets (“source control”), which is especially relevant for asymptomatic or presymptomatic infected wearers who feel well and may be unaware of their infectiousness to others, and who are estimated to account for more than 50 percent. of transmissions. Masks also help reduce inhalation of these droplets by the wearer (“filtration for personal protection”).

"The community benefit of masking for SARS-CoV-2 control is due to the combination of these effects; individual prevention benefit increases with increasing numbers of people using masks consistently and correctly."

New Zealand's Ministry of Health says that wearing a mask "can reduce the risk fo people who have COVID-19 spreading the virus to others".