The World Health Organisation (WHO) has reaffirmed that vaccines remain one of the most effective public health interventions globally, saying over 150 million lives have been saved in the past 50 years through immunisation.

The global health body made the statement on Friday as World Immunisation Week commenced, running from April 24 to April 30, 2026.

According to WHO, the week is aimed at highlighting the importance of vaccines at every stage of life, alongside scientific advances that have produced immunisations against diseases such as malaria, HPV, cholera, dengue, meningitis, RSV, Ebola and mpox.

This year’s observance marks the midpoint of the Immunisation Agenda 2030, a global strategy designed to ensure equitable access to vaccines worldwide.

A progress report released by the organisation showed that while immunisation efforts have prevented millions of deaths in the past five years, many global targets remain off track due to challenges including the COVID-19 pandemic, geopolitical instability, climate disruptions and funding gaps.

WHO noted persistent inequalities in routine vaccination coverage and outbreak prevention, particularly in low- and middle-income countries.

The UN health agency, alongside UNICEF and Gavi, also announced progress under “The Big Catch-up” initiative, which has reached an estimated 18.3 million children aged one to five across 36 countries since its launch in 2023.

The programme has also delivered about 23 million doses of inactivated polio vaccine (IPV), targeting unvaccinated and under-vaccinated children as part of global efforts toward polio eradication.

WHO said the initiative is on track to meet its goal of vaccinating at least 21 million children.