The World Health Organization (WHO) on Wednesday reported that progress toward global vaccination targets for 2015 is far off-track with one in five children worldwide still missing out on routine life-saving immunizations.

WHO's depressing report came ahead of the World Immunization Week which will run from April 24-30.

An estimated 1.5 million deaths could be averted each year from preventable diseases, and WHO is calling for renewed efforts to get progress back on course throughout the world, UN spokesman Stephane Dujarric said at a daily news briefing here.

In 2013, nearly 22 million infants missed out on the required three doses of diphtheria-tetanus-pertussis-containing vaccines ( DTP3), many of them living in the world's poorest countries. WHO is also calling for an end to the unnecessary disability and death caused by failure to vaccinate.

"World Immunization Week creates a focused global platform to reinvigorate our collective efforts to ensure vaccination for every child, whoever they are and wherever they live," said Dr. Flavia Bustreo, WHO assistant director-general for family, women's and children's health. "It is critical that the global community now makes a collective and cohesive effort to put progress towards our 6 targets back on track."

In 2012, all 194 WHO Member States at the World Health Assembly endorsed the Global Vaccine Action Plan (GVAP), a commitment to ensure that no one misses out on vital immunization. However, a recent independent assessment report on GVAP progress rings an alarming bell, warning that vaccines are not being delivered equitably or reliably and that only one of the six key vaccination targets for 2015 is currently on track -- the introduction of under-utilized vaccines.

Many countries experienced large measles outbreaks in the past year, threatening efforts to achieve the GVAP target of eliminating measles by the end of this year.

A global collaborative drive for immunization, which started in the mid-1970s, with the establishment of the Expanded Programme on Immunization in all countries, achieved dramatic results, raising vaccination levels from as low as 5 percent to more than 80 percent in many countries by 2013.

WHO estimates that today immunizations prevent between 2 and 3 million deaths annually and protect many more people from illness and disability.

Although progress has stalled in recent years, this early success demonstrates the potential of vaccines, which are increasingly being extended from children to adolescents and adults, providing protection against diseases such as influenza, meningitis and cervical and liver cancers.