Along with Health Minister Tawfiq Al Rabiah, a woman in a wheelchair and another man were among the first to be administered the vaccine at a centre in Riyadh, on Thursday.
An unrelenting US coronavirus surge pushed besieged hospitals further to the brink as the United States pressed on with its immunisation rollout on Thursday and prepared to ship nearly 6 million doses of a new vaccine on the cusp of winning regulatory approval.
This sparked some confusion — while an advisory panel recommended emergency use approval for Moderna's vaccine on Thursday, the Food and Drug Administration (FDA) has yet to give the final verdict allowing distribution — expected later on Friday.
Tedros Adhanom also warned that the world has plenty of other challenges, saying: "There is no vaccine for poverty, no vaccine for hunger. There is no vaccine for inequality. There is no vaccine for climate change."
"The approval of the Pfizer/BioNTech vaccine will add a further important layer to the kingdom's national COVID-19 response," said Mariam Al Jalahma, CEO of the National Health Regulatory Authority...
The European Medicines Agency said the "historic" step paved the way for vaccinations to finally start within days across the 27-nation EU where cases of the disease are surging.
"Since vaccination requirements vary by country and some require second doses, it is important to visit a travel clinic at least one month prior to travel," said Dr Alia Mohammad Al Dallal.
"The Saudi Food and Drug Authority (SFDA)... has approved the registration of Pfizer-BioNTech COVID-19 vaccine in the kingdom of Saudi Arabia," it said in a statement released by the official Saudi Press Agency.
Crossing the four million does mark comes as result of the efforts made at the country level to contain the pandemic, the Ministry of Health and Prevention announced on Friday.