Immunising children against preventable diseases is critical to achieving United Nations-led goals to reduce child deaths, global health and development chiefs said in New York today.

At an event hosted by UNICEF, the Republic of Kenya and the GAVI Alliance, health ministers, donors and the heads of UN agencies called for the introduction of new vaccines that can dramatically reduce deaths due to diarrhoea and pneumonia, the two biggest killers of children under five.

Kenya's Minister of Public Health and Sanitation, Dr Rose Mugo, said her county's expanded immunisation program has reduced deaths among children from 115 per 1,000 live births in 2003 to 75 per 1,000 live births today – a 35 percent reduction.

"When we are able to introduce new vaccines against diarrhoea and pneumonia we are confident that the number will drop even further," she said.

Dr Guillermo Gonzalez, Nicaragua's former health minister and current Special Advisor to the President, said his country was reaching up to 95 percent of children with routine immunisation.

"Since we introduced the rotavirus vaccine three years ago we have observed 35 to 40 percent reductions in mortality," he said.

Margaret Chan, Director-General of the World Health Organization, said she was proud to lead an organization which together with UNICEF was one of the "midwives" that gave birth to the GAVI Alliance in 2000.

"Vaccines are one of the most cost-effective health interventions and one of the best buys. We appeal to the generosity of donors 'open your purses'," she said. "Diarrhoea and pneumonia are the two biggest killers of children. If you invest (in these new vaccines) you can save millions."

Government donors from Norway, the United Kingdom and the United States also pledged to keep supporting GAVI's global immunisation effort.

The United Kingdom's Secretary of State for International Development, Andrew Mitchell, MP, said it was a "global scandal" that children were still dying from vaccine-preventable diseases, and donors needed to do more.

"We don't want to balance our budgets on the backs of the poorest countries of the world," Mitchell said. "Immunisation is undoubtedly one of the best buys in global health and GAVI is one of the most effective ways of achieving Millennium Development Goal Four. GAVI is focused on results – that is at the heart of our approach to development."

Amie Batson, Deputy Assistant Administrator of the US Agency for International Development (USAID), spoke about the need for smart spending.

"Through the Global Health Initiative, the United States is committed to targeting increased resources in a more effective and efficient way," Batson said. "We need creative new approaches to reach the millions of children who are not immunised because, at the end of the day, we will be judged by the lives we save, not the money we spend."

As world leaders gather at the United Nations this week to find ways to reduce deaths of children and improve the health of mothers, the GAVI Alliance said that decisions made by donor nations now will determine the fate of as many as 4.2 million of the poorest children in the poorest nations—the ones who are most likely to die in the next five years if they don't receive the vaccines that can save their lives.

In the last decade, despite the progress of developing countries in using more childhood vaccines, an estimated eight million children died from pneumococcal disease, a leading cause of pneumonia and meningitis, and five million children died from rotavirus, the major cause of severe diarrhoea among young children that is most deadly in poor nations. Experts predict that the introduction of the two vaccines can eventually save the lives of one million children per year.

GAVI Alliance partners, which include UNICEF and WHO, say they will build on the successes of the Alliance's first decade, when they delivered vaccines against life-threatening diseases to more than 250 million children, an investment that is expected to save 5.4 million lives.

In order to introduce new vaccines against pneumococcal and rotavirus and sustain high immunisation coverage rates in poor countries, GAVI requires US$4.3 billion in new funding.

With widespread introduction of vaccines that can prevent pneumonia and rotavirus, most countries will be meet the critical Millennium Development Goal 4, which calls for a reduction by two-thirds of preventable child deaths by 2015.