Portuguese officials welcome German army medical experts at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)

German army medical experts are seen in a bus at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)

A military transport plane of the German Air Force is seen at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)

German army medical experts disembark at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)

A military transport plane of the German Air Force arrives at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)

German army medical experts arrives at Figo Maduro military airbase in Lisbon, Portugal, on Feb. 3, 2021. Based on a bilateral agreement, a team of German army medical experts arrived in Portugal on Wednesday to assist the country in its fight against the COVID-19 pandemic. (Photo by Pedro Fiuza/Xinhua)