Healthcare workers inform people during the vaccination campaign, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

Serbians arrive to receive the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

Serbians arrive to receive the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

People queue to receive the Chinese-made Sinopharm Covid-19 vaccine, outside the Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

People queue to receive the Chinese-made Sinopharm Covid-19 vaccine, outside the Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

People queue to receive the Chinese-made Sinopharm Covid-19 vaccine, outside the Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

People queue to receive the Chinese-made Sinopharm Covid-19 vaccine, outside the Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

An aerial view shows people receiving the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A health worker informs people who arrive to receive the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

An aerial view shows a woman receiving a Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

An aerial view shows men receiving the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker admnisters a Chinese-made Sinopharm Covid-19 vaccine to a man, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

People wait 15 minutes for possible side effects, after receiving the Chinese-made Sinopharm Covid-19 vaccine in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker admnisters a Chinese-made Sinopharm Covid-19 vaccine to a man, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker admnisters a Chinese-made Sinopharm Covid-19 vaccine to a man, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker prepares a dose of Chinese-made Sinopharm Covid-19 vaccine, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker prepares a dose of Chinese-made Sinopharm Covid-19 vaccine, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker prepares a dose of Chinese-made Sinopharm Covid-19 vaccine, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)

A healthcare worker prepares a dose of Chinese-made Sinopharm Covid-19 vaccine, in Belgrade Fair turned into a vaccination centre, on January 25, 2021. - Serbia launched a mass Covid-19 vaccination campaign and became the first European country to use Chinese-made Sinopharm vaccine, after receiving one million doses of the Sinopharm vaccine, on January 16, 2021. (Photo by Andrej ISAKOVIC / AFP)