Disposable surgical masks for protection against the coronavirus disease (COVID-19) are hung beside a religious altar in a shanty home in Manila, Philippines, May 6, 2020. Picture taken May 6, 2020. REUTERS/Eloisa Lopez

A staff wears a surgical masks and face shield to protect herself from the coronavirus disease (COVID-19) while working at a nail saloon in Taipei, Taiwan, May 5, 2020. Photo taken on May 5, 2020. REUTERS/Ann Wang

A labour union group leader speaks at a May Day rally while wearing a surgical mask to protect herself from the coronavirus disease (COVID-19) in Taipei, Taiwan, May 1, 2020. REUTERS/Ann Wang

Labour union groups gather for a May Day rally while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, May 1, 2020. REUTERS/Ann Wang

Labour union groups gather for a May Day rally while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, May 1, 2020. REUTERS/Ann Wang

Labour union groups gather for a May Day rally while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, May 1, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center trains while wearing a surgical mask to protect himself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center trains while wearing a surgical mask to protect himself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center takes a break between trainings while wearing a surgical mask to protect herself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center trains while wearing a surgical mask to protect himself from coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A trainer teaches students how to box while wearing a surgical mask to protect herself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

Students of a martial arts center train while wearing surgical masks to protect themselves from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center prepares for class while wearing a surgical mask to protect himself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A student of a martial arts center trains while wearing a surgical mask to protect himself from the coronavirus disease (COVID-19) in Taipei, Taiwan, April 30, 2020. Photo taken on April 30, 2020. REUTERS/Ann Wang

A surgical mask is seen discarded on a city sidewalk during the outbreak of the coronavirus disease (COVID-19) in the Brooklyn borough of New York City, New York, U.S., April 7, 2020. REUTERS/Stefan Jeremiah

A worker checks surgical masks on the production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

A worker collects surgical masks on the production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

A worker packs surgical masks on the production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

Members of staff collect surgical masks from a production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

A worker shows a surgical mask with "Made in Taiwan" mark from a production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

A worker wears a surgical mask to prevent pollution to the face masks on the the production line in a factory in Taoyuan, Taiwan April 6, 2020. REUTERS/Ann Wang

A combination of four images shows a surgical mask (top R), a self-made protective mask (top L), a FFP3 Respirator mask (bottom L) and a FFP2 Respirator mask (bottom R) in these illustrations taken, April 6, 2020. REUTERS/Kai Pfaffenbach/Illustration

A surgical mask is seen in this illustration taken, April 6, 2020. REUTERS/Kai Pfaffenbach/Illustration

A surgical mask is seen as the spread of the coronavirus disease (COVID-19) continues in Hanau, Germany, April 6, 2020. REUTERS/Kai Pfaffenbach

Equipped to prevent the spread of coronavirus with a surgical glove, a face mask and a long stick, a jobless man named Paul panhandles at an intersection in Falls Church, Virginia, U.S., April 3, 2020. REUTERS/Kevin Lamarque

Equipped against the spread of coronavirus with a surgical glove, a face mask and a long stick, a jobless man named Paul panhandles at an intersection in Falls Church, Virginia, U.S., April 3, 2020. REUTERS/Kevin Lamarque

Wearing a mask and a surgical glove to prevent coronavirus spread, a jobless man named Paul panhandles at an intersection in Falls Church, Virginia, U.S., April 3, 2020. REUTERS/Kevin Lamarque

Oleg Karpov, General Director of N.I. Pirogov National Medical and Surgical Centre, wears a protective mask during a demonstration prior to the opening of a new section for treatment of patients, affected by the coronavirus disease (COVID-19), in Moscow, Russia April 3, 2020. REUTERS/Maxim Shemetov

Women wearing protective masks speak during a demonstration prior to the opening of a new section for treatment of patients, affected by the coronavirus disease (COVID-19), at N.I. Pirogov National Medical and Surgical Centre in Moscow, Russia April 3, 2020. REUTERS/Maxim Shemetov

A woman sews protective masks in a factory that produces sterilised surgical equipment and medical clothings, as Egypt ramps up efforts to slow the spread of coronavirus disease (COVID-19), in Sadat, Egypt, March 15, 2020. Picture taken March 15, 2020. REUTERS/Mohamed Abd El Ghany

A woman wearing a protective face mask works at a factory that produces sterilised surgical equipment and medical clothings, as Egypt ramps up efforts to slow the spread of coronavirus disease (COVID-19), in Sadat, Egypt, March 15, 2020. Picture taken March 15, 2020. REUTERS/Mohamed Abd El Ghany

A woman wearing a protective face mask works at a factory that produces sterilised surgical equipment and medical clothings, as Egypt ramps up efforts to slow the spread of coronavirus disease (COVID-19), in Sadat, Egypt, March 15, 2020. Picture taken March 15, 2020. REUTERS/Mohamed Abd El Ghany

A woman wearing a protective face mask works at a factory that produces sterilised surgical equipment and medical clothings, as Egypt ramps up efforts to slow the spread of coronavirus disease (COVID-19), in Sadat, Egypt, March 15, 2020. Picture taken March 15, 2020. REUTERS/Mohamed Abd El Ghany

A woman arranges protective face masks in a factory that produces sterilised surgical equipment and medical clothings, as Egypt ramps up efforts to slow the spread of coronavirus disease (COVID-19), in Sadat, Egypt, March 15, 2020. Picture taken March 15, 2020. REUTERS/Mohamed Abd El Ghany

Staff member works inside a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Staff work inside a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

A presidential security officer wears a face mask for protection against the coronavirus disease (COVID-19) outbreak, during President Tsai Ing-wen's visit to a factory for non woven filter fabric that is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Staff member works inside a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

A staff wears a face mask with a Taiwanese flag design, as protection due to the coronavirus disease (COVID-19) outbreak, at a factory for non woven filter fabric used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Taiwanese president Tsai Ing-Wen listens to a presentation at a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Taiwanese president Tsai Ing-Wen speaks at a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Taiwanese president Tsai Ing-Wen answers the media during a visit to a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Taiwanese president Tsai Ing-Wen poses for a group photo at a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang

Taiwanese president Tsai Ing-Wen visits a non woven filter fabric factory, where the fabric is used to make surgical face masks, in Taoyuan, Taiwan, March 30, 2020. REUTERS/Ann Wang TPX IMAGES OF THE DAY

A surgical mask is seen in East Meadow in Central park during the outbreak of the coronavirus disease (COVID-19), in New York City, U.S., March 29, 2020. REUTERS/Jeenah Moon REFILE - CLARIFYING LOCATION

A mannequin is seen displayed with a surgical mask where a vendor was selling packages of surgical masks on a street corner in the Chelsea neighborhood of Manhattan, during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 27, 2020. REUTERS/Mike Segar

A vendor sells packages of surgical masks on a street corner in the Chelsea neighborhood of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 27, 2020. REUTERS/Mike Segar

A mannequin is seen displayed with a surgical mask where a vendor was selling packages of surgical masks on a street corner in the Chelsea neighborhood of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 27, 2020. REUTERS/Mike Segar

A construction worker holds up a package of surgical masks where a vendor was selling them on a street corner in the Chelsea neighborhood of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 27, 2020. REUTERS/Mike Segar

A vendor sells packages of surgical masks on a street corner in the Chelsea neighborhood of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 27, 2020. REUTERS/Mike Segar

A man pauses outside a store with a sign advertising surgical masks for sale on the upper west side of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 25, 2020. REUTERS/Mike Segar

A worker sits inside a store beneath a sign advertising surgical masks for sale on the upper west side of Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., March 25, 2020. REUTERS/Mike Segar

A pig figurine wearing a surgical mask is displayed near the front desk of the Osaka Corona Hotel in Osaka, Japan March 19, 2020. Picture taken March 19, 2020. REUTERS/Mari Saito

A commuter wearing surgical mask walks inside metro installations as the coronavirus disease (COVID-19) outbreak continues, in Mexico City, Mexico March 24, 2020. REUTERS/Gustavo Graf