America’s top doctor has urged people to stop buying face masks, insisting they “are not effective in preventing” the spread of coronavirus among the general population.

Dr Jerome Adams, the surgeon general of the US, has echoed the Centers for Disease Control and Prevention (CDC) in warning the public that they do not need to wear a mask if they are healthy or not caring for someone who is ill.

“Seriously people — STOP BUYING MASKS!” Dr Adams said in a tweet over the weekend. “They are NOT effective in preventing general public from catching #Coronavirus, but if health care providers can’t get them to care for sick patients, it puts them and our communities at risk!”

In another tweet, he said the best way to protect against coronavirus, otherwise known as Covid-19, is to wash hands regularly, and for those who are feeling ill to stay at home.

The warning comes amid a surge in demand for face masks across America, in particular the N95, which is thicker and fits more tightly around the mouth and nose.

Coronavirus: Streets around world left empty Show all 10 1 /10 Coronavirus: Streets around world left empty Coronavirus: Streets around world left empty A man wearing a face mask crosses a road in Wuhan, the epicentre of the novel coronavirus outbreak. Reuters Coronavirus: Streets around world left empty A view of the empty entrance to the UniversitÃ Cattolica (Catholic University) in Milan, northern Italy, on 24 February, 2020. EPA Coronavirus: Streets around world left empty Empty streets in Daegu, South Korea, on 23 February, 2020. EPA Coronavirus: Streets around world left empty Empty streets in Daegu, South Korea, on 23 February 2020. EPA Coronavirus: Streets around world left empty A lone sanitation worker sits near the closed Hankou Railway Station in Wuhan, Hubei province, China, on February 24, 2020. Reuters Coronavirus: Streets around world left empty A view of a deserted street in Codogno, northern Italy, on February 23, 2020. EPA Coronavirus: Streets around world left empty Italian police officers set a road block in Codogno, Northern Italy, on Monday, Feb. 24, 2020. AP Coronavirus: Streets around world left empty A supermarket closed in Codogno, one the northern Italian towns placed under lockdown, on February 23, 2020. EPA Coronavirus: Streets around world left empty A lone cyclist wearing sanitary masks pedals in the center of Codogno, Northern Italy. LaPresse via AP Coronavirus: Streets around world left empty An empty road at the entrance of the small Italian town of Codogno on February 23, 2020. AFP via Getty

Amazon users have searched for the N95 mask more than 862,000 times in the last 30 days, according to data released by Helium 10, a software company that assists retailers. In December, only 4,500 searches were made for the mask over the space of 30 days.

Increasing demand has also seen prices rocket. Mike Bowen, the executive vice president of Prestige Ameritech, an N95 manufacturer in Texas, described the mask as cheap as “a gumball”, but Amazon sellers have been advertising them for at least £7 each.

“They’re cheap. They’re automated. They’re not handmade,” Mr Bowen added.

According to Dr William Schaffner, a preventive medicine professor at the Vanderbilt University School of Medicine, the urge to go out and buy masks was a “psychological thing”.

“The coronavirus is coming, and we feel rather helpless,” he told CNN. “By getting masks and wearing them, we move the locus of control somewhat to ourselves.”

Vice president Mike Pence, who is coordinating the government’s response to the coronavirus outbreak, said on Saturday during a press briefing with Donald Trump that the administration has contracted the manufacturing giant 3M to produce 30 million more masks a month.

But as Dr Adams outlined, the concern among officials is that rising sales of face masks will deprive health workers of the equipment needed to effectively and safely treat patients.

“There are severe strains on protective equipment around the world,” Dr Michael Ryan, executive director of the health emergency programme at the World Health Organisation, said on Friday. “Our primary concern is to ensure that our front line health workers are protected and that they have the equipment they need to do their jobs.

“There are limits to how a mask can protect you from being infected. The most important thing everyone can do is wash your hands, keep your hands away from your face and observe very precise hygiene.”