French Health Minister Olivier Veran (L) listens as French doctor and professor in paediatric immunology Alain Fischer speaks during a press conference on the time limit for the injection with the second dose of the Pfizer-BioNTech coronavirus vaccine, in Paris, France January 26, 2021. Bertrand Guay/Pool via REUTERS

French Health Minister Olivier Veran (L) listens as French doctor and professor in paediatric immunology Alain Fischer speaks during a press conference on the time limit for the injection with the second dose of the Pfizer-BioNTech coronavirus vaccine, in Paris, France January 26, 2021. Bertrand Guay/Pool via REUTERS

French Health Minister Olivier Veran (L) and French doctor and professor in paediatric immunology Alain Fischer hold a press conference on the time limit for the injection with the second dose of the Pfizer-BioNTech coronavirus vaccine, in Paris, France January 26, 2021. Bertrand Guay/Pool via REUTERS

French doctor and professor in paediatric immunology Alain Fischer speaks during a press conference on the time limit for the injection with the second dose of the Pfizer-BioNTech coronavirus vaccine, in Paris, France January 26, 2021. Bertrand Guay/Pool via REUTERS

Professor Andrew Pollard, Director of the Oxford Vaccine Group (OVG), and a professor of Paediatric Infection and Immunity reacts as he receives the Oxford University/AstraZeneca COVID-19 vaccine at the Churchill Hospital in Oxford, Britain January 4, 2021. Steve Parsons/Pool via REUTERS

Professor Andrew Pollard, Director of the Oxford Vaccine Group (OVG), and a professor of Paediatric Infection and Immunity receives the Oxford University/AstraZeneca COVID-19 vaccine from nurse Sam Foster at the Churchill Hospital in Oxford, Britain January 4, 2021. Steve Parsons/Pool via REUTERS

Professor Andrew Pollard, Director of the Oxford Vaccine Group (OVG), and a professor of Paediatric Infection and Immunity receives the Oxford University/AstraZeneca COVID-19 vaccine from nurse Sam Foster at the Churchill Hospital in Oxford, Britain January 4, 2021. Steve Parsons/Pool via REUTERS

A hospitalized child touches the hand of her mother through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child meets his father through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child meets his best friend through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child hugs and kisses her mother through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child touches the hand of his father through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child holds his father's hand through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child hugs his mother through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A hospitalized child meets his father through a plastic protection without risk of contamination or transmission of the coronavirus disease (COVID-19) at the Department of paediatric rehabilitation and developmental disabilities of IRCCS at the San Raffaele hospital, after children have wished for Christmas to see and hug their relatives, in Rome, Italy, December 22, 2020. REUTERS/Yara Nardi

A member of the Slovenian Cave Rescue Association dressed as Santa Clause rappels down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Members of the Slovenian Cave Rescue Association dressed as Santa Clauses pose after rappelling down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Members of the Slovenian Cave Rescue Association dressed as Santa Clauses rappel down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

A member of the Slovenian Cave Rescue Association dressed as Santa Clause waves after rappelling down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Members of the Slovenian Cave Rescue Association dressed as Santa Clauses rappel down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

A member of the Slovenian Cave Rescue Association dressed as Santa Clause rappels down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Members of the Slovenian Cave Rescue Association dressed as Santa Clauses rappel down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

A member of the Slovenian Cave Rescue Association dressed as Santa Clause rappels down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Members of the Slovenian Cave Rescue Association dressed as Santa Clauses rappel down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

A member of the Slovenian Cave Rescue Association dressed as Santa Clause rappels down the glass facade of a paediatric hospital in Ljubljana, Slovenia, December 21, 2020. REUTERS/Borut Zivulovic

Rebecca Zammit Lupi, a 14-year-old cancer patient, receives a gift from radiographers Maria Elena Grech and Angelina Dimitrova after her final radiotherapy treatment session at Sir Anthony Mamo Oncology Centre in Mater Dei Hospital, during the coronavirus disease (COVID-19) outbreak, in Tal-Qroqq, Malta June 4, 2020. Dimitrova said "It's always bittersweet to have a paediatric patient. Their presence brings joy, but the reason behind their attendance harbours a lot of sorrow. Although we recognise that each patient is on an earth shattering and life-altering journey, when it comes to children, it always hits a softer spot, which is why we enjoy celebrating the ends of their treatments that little bit louder and commemorating it with a small gift personal to every child." REUTERS/Darrin Zammit Lupi SEARCH "REBECCA LUPI" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES THE IMAGES SHOULD ONLY BE USED TOGETHER WITH THE STORY - NO STAND-ALONE USES

Health care workers of the Juan P. Garrahan Paediatric Hospital protest in demand of better sanitary working conditions and salaries, amid the coronavirus disease (COVID-19) outbreak in Buenos Aires, Argentina August 6, 2020. REUTERS/Agustin Marcarian

Health care workers of Juan P. Garrahan Paediatric Hospital protest in demand of better sanitary working conditions and salaries, amid the coronavirus disease (COVID-19) outbreak in Buenos Aires, Argentina August 6, 2020. REUTERS/Agustin Marcarian

Health care workers of the Juan P. Garrahan Paediatric Hospital protest in demand of better sanitary working conditions and salaries, amid the coronavirus disease (COVID-19) outbreak in Buenos Aires, Argentina August 6, 2020. REUTERS/Agustin Marcarian

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) poses in a room at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) practices re-education exercises with physiotherapist Laura Ciocanas at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) practices re-education exercises with physiotherapist Laura Ciocanas at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) poses in a room at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) practices re-education exercises with physiotherapist Laura Ciocanas at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

French paediatric neurosurgeon Georg Dorfmuller (61-year-old) poses in a room at the post COVID-19 unit of the Le Parc Hospital in Taverny near Paris during the outbreak of the coronavirus disease (COVID-19) in France, April 30, 2020. REUTERS/Benoit Tessier

Klaus-Michael Debatin, medical director of paediatrics of Ulm's University Clinic, speaks at a news conference in Ulm, Germany, January 30, 2020. REUTERS/Andreas Gebert

General view of the paediatric clinic of the Ulm University Clinic in Ulm, Germany, January 30, 2020. REUTERS/Andreas Gebert

General view of the paediatric clinic of the Ulm University Clinic in Ulm, Germany, January 30, 2020. REUTERS/Andreas Gebert

General view of the paediatric clinic of the Ulm University Clinic in Ulm, Germany, January 30, 2020. REUTERS/Andreas Gebert

General view of the paediatric clinic of the Ulm University Clinic in Ulm, Germany, January 30, 2020. REUTERS/Andreas Gebert

Kenai Rivero who is two months old and has been diagnosed with malnutrition, is checked by a doctor during a special event for children with nutritional problems organised by Catholic relief agency Caritas, at a church in Barquisimeto, Venezuela, August 10, 2019. "I went to the paediatric hospital, and they gave me an appointment for a month later because the nutritionist was on leave." "I went to the nutrition institute, and they gave me an appointment for the Monday of the following week," said Francys when describing how she has been looking for help with her son. "I'm looking everywhere to get him checked because I can't stay at home waiting and seeing as he doesn't gain weight." REUTERS/Carlos Garcia Rawlins SEARCH "VENEZUELA MALNUTRITION" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. TPX IMAGES OF THE DAY

The grandmother of Palestinian boy Yehia al-Samna, 8, watches him as he undergoes a kidney dialysis at a public paediatric hospital in Gaza City, March 28, 2017. REUTERS/Mohammed Salem SEARCH "GAZA HEALTH" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Palestinian boy Mohammed al-Laham undergoes a kidney dialysis at a public paediatric hospital in Gaza City, March 28, 2017. REUTERS/Mohammed Salem SEARCH "GAZA HEALTH" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Palestinian boy Mohammed al-Laham undergoes a kidney dialysis at a public paediatric hospital in Gaza City, March 28, 2017. REUTERS/Mohammed Salem SEARCH "GAZA HEALTH" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

The grandmother of Palestinian boy Yehia al-Samna, 8, watches him as he undergoes a kidney dialysis at a public paediatric hospital in Gaza City, March 28, 2017. REUTERS/Mohammed Salem SEARCH "GAZA HEALTH" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A woman rests in bed with her children in the paediatric ward at the Medecins Sans Frontieres (MSF) hospital inside the United Nations Mission in South Sudan (UNMISS) base, Bentiu, Rubkona County, South Sudan March 23, 2017. Picture taken March 23, 2017. REUTERS/Siegfried Modola TPX IMAGES OF THE DAY

A mother with her child sleep in a bed of the paediatric ward of an hospital in the United Nations Mission in South Sudan (UNMISS) Protection of Civilian site (PoC), outside the capital Juba, South Sudan, January 24, 2017. Picture taken January 24, 2017. REUTERS/Siegfried Modola

Pope Francis gives medicine to a young patient while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis talks with a young patient while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi

A young patient touches Pope Francis during his visit to pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis embraces young patients while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis embraces young patients while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis talks with people and young patients while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis embraces a young patient while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis talks with people while visiting pediatric hospital "Federico Gomez" in Mexico City, February 14, 2016. REUTERS/Max Rossi

Pope Francis talks with a young patient while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi

Pope Francis puts rosary beads on a patient while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi

Pope Francis kisses a child while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi

Pope Francis kisses a girl while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi

Pope Francis touches a girl while visiting pediatric hospital "Federico Gomez" in Mexico, February 14, 2016. REUTERS/Max Rossi