Medical workers prepare to give vaccines to children in Damascus, capital of Syria, on June 18, 2020. The Syrian government has regularly carried out vaccination campaigns for children. (Photo by Ammar Safarjalani/Xinhua)

Medical workers give a vaccine to a child in Damascus, capital of Syria, on June 18, 2020. The Syrian government has regularly carried out vaccination campaigns for children. (Photo by Ammar Safarjalani/Xinhua)

A medical worker gives a vaccine to a child in Damascus, capital of Syria, on June 18, 2020. The Syrian government has regularly carried out vaccination campaigns for children. (Photo by Ammar Safarjalani/Xinhua)

Medical workers prepare to give vaccines to children in Damascus, capital of Syria, on June 18, 2020. The Syrian government has regularly carried out vaccination campaigns for children. (Photo by Ammar Safarjalani/Xinhua)