Donors promised to give a global vaccines body $3.9 billion to help it protect millions of children from diseases like measles, pneumonia and yellow fever.
At a one-day pledging conference in London on Monday, British Prime Minister David Cameron announced his country would provide $1.27 billion of new funding up to 2015.
Canada said it would increase its commitment to the Global Alliance for Vaccines and Immunization to $63.6 million over five years from the original pledge of $48.9 million over five years.
"Canada will continue to support the work of the GAVI Alliance to immunize and save the lives of millions of children in developing countries," said Bev Oda, the minister of international co-operation.
Australia announced Sunday it would commit $206 million, and the Bill & Melinda Gates Foundation declared it would donate more than $0.98 billion to the cause.
GAVI is an alliance of organizations including the Gates Foundation, the World Health Organization, UNICEF, major vaccine makers and others. The group buys injections for the world's poorest countries. They estimate about 2 million children die every year from diseases that could have been prevented with a shot.
"Today is an important moment in our collective commitment to protecting children in developing countries from disease," said Ellen Johnson Sirleaf, president of Liberia, in a statement.
Daniel Berman, a vaccines expert at Doctors Without Borders, said it was exciting so much money had been pledged and that many lives would be saved. But he questioned whether the millions of taxpayer dollars would be spent properly.
'Screams conflict of interest'
Executives from major vaccine companies also sit on GAVI advisory boards and influence their purchasing policies. GlaxoSmithKline Plc and Pfizer Inc. each get a subsidy of $220 million to produce pneumonia vaccines — which are then purchased by GAVI for about $3.42 a dose.
The subsidies are intended to convince vaccine makers to produce injections that aren't normally profitable. But in 2008, Pfizer reported making nearly $2.93 billion in sales from the shot. "Why are we lining the pockets of big pharma like this?" Berman asked.
"That just screams conflict of interest and corporate welfare to us."
Health officials hope to vaccinate more than 250 million children, saving about 4 million lives in the next few years.
"For the first time in history, children in developing countries will receive the same vaccines against diarrhea and pneumonia as children in rich countries," said Bill Gates, co-chair of the Gates Foundation, in a statement. "Together we must do more to ensure that all children — no matter where they live — have equal access to life-saving vaccines."
Previous research has been raised about whether vaccines bought by GAVI are actually making it to the children who need them.
Several years ago, a study published in the journal Lancet showed dozens of developing countries exaggerated figures on how many children were vaccinated against deadly diseases, allowing them to get more money from GAVI. Researchers said only half as many children were immunized than was claimed by countries.
Other experts warned more money wouldn't solve the problem and that donating vaccines to countries with broken health systems might mean they just end up sitting in warehouses.
"We need to be mindful of the fact that investment in vaccines is not the magic answer to global health issues such as pneumonia and diarrhea," said Sophie Harman, a public health expert at City University in London. "Without proper funding commitments to health infrastructure …any investment in vaccines will be redundant."