Nigeria was cited as one of the countries in the world with a high number of under- and unvaccinated children of 3 million.
Studies conducted jointly by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) accounted for 11.7 of the world's 19.4 million under- and un-vaccinated adolescents.
Other poorer countries are India (2.6 million) and Pakistan (1.4 million).
This even points to a gloomy picture as a statistic, in which global protection against four diseases considered to be a measure of total coverage – diphtheria, tetanus, pertussis and measles – is "stalled" and 86 percent in the last nine years.
United Nations health experts urge governments to increase vaccination coverage and target 95 percent. They said that only 118 countries reached a coverage threshold of 90 percent in 2018.
"Vaccines are one of our key tools to prevent outbreaks and protect the world," Dr. Tedros Adhanom Ghebreyesus, Director-General of WHO.
] He further said that while most children in the world are vaccinated, "far too many are left behind … It is often those who are most at risk – the poorest, the most marginalized, who are affected by conflict are or are being expelled from their homes – they are still missing. "
The region with the best vaccination in 2018 is according to the data Europe, whose quota of more than 90 percent was 18 percent higher than the region with the Worst Performance in Africa
The 19.4 million children worldwide who have not received three doses of vaccine to protect themselves from diphtheria, tetanus and pertussis – two-thirds did not receive even a starting dose.
Most unvaccinated children came by themselves m The world's poorest countries with conflict-affected countries are also contributing to the high numbers.
About half of these children live in 16 countries: Afghanistan Central African Republic, Chad, Democratic Republic of the Congo (DR Congo), Ethiopia, Haiti, Iraq, Mali, Niger, Nigeria, Pakistan, Somalia, South Sudan, Sudan, Syria and Yemen.