Countries will observe the first World Immunization Week globally starting Saturday, the WHO said Friday.
Given to immune a person against infectious diseases, vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease.
"Nearly 9.7 million children in the region still do not get the most basic of vaccines like the third dose of DTP-containing vaccine. Immunisation is one of the most cost-effective public health interventions," said Samlee Plianbangchang, WHO regional director for Southeast Asia.
"Growing opportunities through new funding as well as research and development initiatives should not go in vain due to the lack of perceived benefit. We need to increase public awareness and ensure that the general public understands how immunisation saves lives," Plianbangchang added.
The current estimated immunisation coverage for DTP3-containing vaccines in Southeast Asia remains relatively low at 73 percent, the WHO said.
While some countries have achieved high national coverage (90-95 percent), others are experiencing challenges in establishing universal coverage in different states, provinces and districts that pose a variety of barriers.
The WHO Regional Committee for Southeast Asia adopted a resolution in September 2011, endorsed by all 11 member states, declaring 2012 as the year of intensification of routine immunisation.
"As part of intensification efforts, North Korea, the Maldives, Myanmar and Timor-Leste will introduce pentavalent vaccine in their routine immunisation schedule. Other countries are currently assessing the introduction of other vaccines by gathering evidence-based data on disease burden, as well as through financial sustainability studies," the WHO said in a statement.