Registered Nurse Sheryal Valencic administers a dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Foster Knutson retrieves vials of the JYNNEOS smallpox and monkeypox vaccine from a cooler during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Dr. Ellen Paige administers a dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Lisa Beckett fills a syringe with one dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Dr. Ken Iserson administers a dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Foster Knutson fills a syringe with a dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Michael Katz passes a tray of syringes containing one dose of the JYNNEOS smallpox and monkeypox vaccine during clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Roseanne Lee fills a syringe with one dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacists fill syringes with the JYNNEOS smallpox and monkeypox vaccine during a clinic offered by the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Volunteer pharmacist Foster Knutson fills a syringe with a dose of the JYNNEOS smallpox and monkeypox vaccine during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Syringes filled with one dose of JYNNEOS smallpox and monkeypox vaccine sit on a tray during a clinic through the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Vials of the JYNNEOS smallpox and monkeypox vaccine are placed on a table during a clinic offered by the Pima County Department of Public Health at Abrams Public Health Center in Tucson, Arizona, U.S., August 20, 2022. REUTERS/Rebecca Noble 

Josefa Espinosa, 65, and her husband Francisco Vivas, 79, show scars on their arms from the vaccination against smallpox received during their childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

Josefa Espinosa, 65, and her husband Francisco Vivas, 79, show scars on their arms from the vaccination against smallpox received during their childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

Josefa Espinosa, 65, shows a scar on her arm from the vaccination against smallpox received during her childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

Josefa Espinosa, 65, and her husband Francisco Vivas, 79, show scars on their arms from the vaccination against smallpox received during their childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

Josefa Espinosa, 65, shows a scar on her arm from the vaccination against smallpox received during her childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

Josefa Espinosa, 65, and her husband Francisco Vivas, 79, show scars on their arms from the vaccination against smallpox received during their childhood, in Ronda, Spain, May 25, 2022. REUTERS/Jon Nazca 

An employee of the vaccine company Bavarian Nordic works in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth 

An employee of the vaccine company Bavarian Nordic works in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An employee works on a vaccine based on the monkeypox vaccine that has already been developed by the vaccine company Bavarian Nordic at a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An employee of the vaccine company Bavarian Nordic works in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An employee of the vaccine company Bavarian Nordic shows a picture of a vaccine virus on a display in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An employee of the vaccine company Bavarian Nordic works in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An employee of the vaccine company Bavarian Nordic works in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

A view through microscope shows chicken embryo fibroblast cells being used to multiply vaccine viruses of the vaccine company Bavarian Nordic in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

Heinz Weidenthaler, Vice President Clinical Strategy, Infectious Diseases at Bavarian Nordic, poses in a laboratory of vaccine company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth REFILE - QUALITY REPEAT
 

Heinz Weidenthaler, Vice President Clinical Strategy, Infectious Diseases at Bavarian Nordic, poses in a laboratory of the vaccine company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth REFILE - QUALITY REPEAT 

An employee of the vaccine company Bavarian Nordic shows a container with fibroblast cells from chicken embryos for the propagation of vaccine viruses in a laboratory of the company in Martinsried near Munich, Germany, May 24, 2022. The company, headquartered in Denmark, is the only one in the world to have approval for a smallpox vaccine called Jynneos in the U.S. and Imvanex in Europe, which is also effective against monkeypox. REUTERS/Lukas Barth
 

An infant lies on the back of a woman as she performs a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for the betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri TPX IMAGES OF THE DAY 

Women hold earthen pots with fire during a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for the betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri 

A woman holds earthen pots with fire during a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for the betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri 

An infant lies on the back of a woman as she performs a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for the betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri 

Women lie on a road as they perform a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri 

Women lie in an alley as they perform a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for the betterment of their family and society, in Kolkata, India, March 28, 2019. REUTERS/Rupak De Chowdhuri 

Locals prepare food during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Food is prepared during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals attend church during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

A local tends a bonfire during the Procesion del Humo, the Procession of Smoke in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

A local tends a bonfire during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

A local tends a bonfire during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Locals take part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

Bearers carry the statue of St Andres during the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

A man takes part in the Procesion del Humo, the Procession of Smoke, in Arnedillo, Spain, November 25, 2018. Bonfires are lit on the last Sunday of November in honour of St Andres, venerated in the town following recovery from a smallpox epidemic in 1888. REUTERS/Vincent West 

A girl lies on a road as she performs a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for betterment of their family and society, in Kolkata, India, April 14, 2018. REUTERS/Rupak De Chowdhuri TPX IMAGES OF THE DAY 

A child reacts as a Hindu woman steps over him in a ritual seeking blessings for the child from the Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for betterment of their family and society, in Kolkata, India, April 14, 2018. REUTERS/Rupak De Chowdhuri 

A girl lies on a road as she performs a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for betterment of their family and society, in Kolkata, India, April 14, 2018. REUTERS/Rupak De Chowdhuri 

Women hold earthen pots with fire during a ritual as they worship Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which devotees pray for betterment of their family and society, in Kolkata, India, April 14, 2018. REUTERS/Rupak De Chowdhuri 

Hindu devotees lie on a road as they perform a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which they pray for betterment of their family and society, in Kolkata April 15, 2017. REUTERS/Rupak De Chowdhuri 

Women lie on a road as they perform a ritual while worshipping Sheetala Mata, the Hindu goddess of smallpox, during Sheetala Puja in which they pray for betterment of their family and society, in Kolkata April 15, 2017. REUTERS/Rupak De Chowdhuri