A revolutionary meningitis vaccine will reach the 100 millionth person this week in a region of Africa that has been plagued by the deadly epidemic for more than a century.
The milestone will take place in northern Nigeria, part of Africa's "meningitis belt", where the country is conducting its seasonal immunisation campaign against the disease.
This comes just two years after the vaccine, known as the MenAfriVac, was launched in Burkina Faso. Since then, nine other countries have held vaccination campaigns to protect people against meningitis A.
Seasonal meningitis A can cause painful inflammation of the lining around the brain and the spine that can kill within 48 hours. Those who do survive often face severe learning difficulties, deafness, or amputated limbs. Children and young adults are the most vulnerable and at risk.
"Meningitis has affected the poorest families in countries of the Sahel, in the worst cases killing one third of the affected community," said Geeta Rao Gupta of UNICEF. "But now campaigns are bringing hope to the poor families of previously unreached communities, which are mobilising their members around this safe, effective and affordable vaccine."
Nigeria alone will vaccinate 16 million people over the next two weeks and by the end of this year, the vaccine will have reached more than 112 million people, providing widespread and long-awaited protection.