As the global pandemic continues, bands have started offering a new piece of must-have merchandise alongside their T-shirts and hoodies - face masks.

Metal acts like Megadeth, Korn and Thursday have led the way, listing masks on their online stores.

My Chemical Romance are selling a stockpile of masks they designed before the pandemic for a show in the desert.

The proceeds will go to a fund for those in live music industry who have lost their jobs because of Covid-19.

"We had these masks made to keep you dust-free in the desert, a show that never happened, never will," the band said in a statement. 

Perhaps, they suggested, "we were unknowingly waiting for the right time" to send them to fans.

Megadeth's masks, which feature their mascot Vic Rattlehead, are being given away to anyone who places an order on their online shop, with a portion of proceeds going towards coronavirus relief.

A line of surgical masks emblazoned with the Korn logo have sold out on the band's official website - but they promise more stock is on its way.

In the US, where the Center Of Disease Control has recommended the use of face coverings to slow the spread of coronavirus, one manufacturer estimates that four to six billion masks will be produced and sold in the next 12 months.

The UK government's scientific advisers were due to meet on Tuesday to discuss whether the public should be urged to wear masks.

The music merchandise industry, which was worth $3.5bn (£2.8bn) last year, has been quick to respond to the demand.

The landscape has shifted dramatically since Latin pop star J Balvin was accused of cashing in on the coronavirus crisis when he tried to sell branded face masks on his online store last month.

He issued a swift apology, saying the promotion "didn't have my consent".

"This is not the way I act, even less in a moment like this," he added, as the gear was removed from his website.

So why aren't bands like Megadeth and Korn being called out in the same way?

"I think the tide has changed," says Christiaan Munro, founder and co-owner of live music company Sandbag, which has created merchandise for acts including The Chemical Brothers, Radiohead, Bastille and Blink-182.

"When coronavirus first happened, the face mask was seen as a very negative and scary image. Now, it's going to be something that you wear to the shops.

"It's become an essential rather than a gimmick, and it will become a fashion accessory. That will be the progression."

Munro says his company has been contacted by several artists interested in creating their own masks, and "the supply chain is being worked out right now".

In many cases, old T-shirts will be recycled to create the masks, meaning "each one will be unique".

"Weirdly enough, we were already making a lot of masks," Tony Holiday, president of the Toronto-based Kt8 Merchandise Company told Billboard magazine last week.

"A lot of our acts are EDM and in that scene, bandanas and face masks have been popular at festivals for years because of the dust factor. So with the recent demand in face masks, we were already set up to deliver."

Kt8 is donating some of its proceeds to local hospitals and charities, while other merchandise manufacturers are donating surplus stock to be turned into masks and head caps for hospitals.

Meanwhile, a number of major fashion brands have also been making protective equipment for medical professionals, with some designers bringing out ranges of masks for public sale.

Munro notes that masks were also popular among Asian music fans before the Covid-19 pandemic.

"If you see pictures of people in the cities like Tokyo and Beijing, they worry about Sars or pollution - so there are a lot of face masks being worn," he says.

"But they've also been selling face masks on market stalls in downtown LA, in the fashion district, for a long time. It's a utility item and then it flowed over into fashion."

That's why pop acts like Ariana Grande and Little Mix had masks on their merchandise stands before the coronavirus outbreak; while Billie Eilish wore a Gucci mask to Glastonbury and the Grammy Awards, and sells her own branded masks at Urban Outfitters.

It should be noted that masks made of fabric or cloth may only provide a small degree of protection and could even increase the risk of infection, according to the European Centre for Disease Control.

Munro says that's why UK acts have not so far been inclined to commission their own line of face coverings.

"But I think we'll follow the US, with bands promoting face masks as the general population decides to wear them, with or without instruction from government," he says.

And while most artists are using the merchandise to raise money for charity, Munro says some will be looking to "supplement the income they've lost through tours being cancelled".

Sales of T-shirts and hoodies have remained steady during the lockdown, he notes, which could be a lifeline for some smaller acts.

"Interestingly, when tours got cancelled, those artists that have put their tour merchandise [on sale] with the dates that never happened on the back, they've done really well," he says.

"It was surprising that people have been supporting the tours even though they didn't get to go to them." BBC