* Money would fund GAVI's programmes from 2016 to 2020
* GAVI works with drugmakers to cut vaccine costs for poor
* 1.5 mln children a year die of vaccine-preventable disease (Updates with pledge from European Union, price freeze fromGSK)
By Kate Kelland
LONDON, May 20 (Reuters) - The GAVI global vaccines allianceappealed on Tuesday for $7.5 billion to help immunize another300 million children against life-threatening diseases between2016 and 2020 and save up to 6 million more lives.
GAVI said the additional investments, which it hopes to getmainly from global health philanthropists and the governments ofdeveloped nations, could double the number of lives savedthrough GAVI-supported vaccines to an estimated 12 million.
"We are faced with an historic opportunity to supportcountries to build sustainable immunisation programmes that willprotect entire generations of children," the group's chairman,Dagfinn Hoybraten, said in a statement.
"The investments we all make now can ensure the equivalentof two children every second will be reached with GAVI-supportedvaccines for five years and secure the future health andeconomic prosperity of all our children in years to come."
GAVI, which is backed by the Bill & Melinda GatesFoundation, the World Health Organisation (WHO), the World Bank,UNICEF, donor governments and others, funds immunisationprogrammes for nations that cannot afford standard prices.
The group targets common but deadly diseases such aspneumonia, diarrhoea and cervical cancer and says it has alreadysaved around 6 million lives since its launch in 2000.
Seth Berkley, GAVI's chief executive, told Reuters thealliance's target of an extra $7.5 billion would be added to $2billion already in hand for 2016-2020.
This is around 15 percent more than GAVI has for the currentfive-year period, he said, and is necessary because around 1.5million children die each year of vaccine-preventable diseases.
The European Union announced in response on Tuesday that itwould pledge 175 million euros ($240 million) in funding for thealliance for 2014-2020.
Berkley said such programmes would produce gains worth $80billion to $100 billion, by cutting the cost of treating illnessand by keeping people well and productive into adulthood.
GAVI uses its private and government donors' backing tonegotiate with pharmaceutical firms such as GlaxoSmithKline, Merck and Pfizer to bring down vaccineprices for the poor. It then works with partners to bulk-buy anddeliver vaccines to countries whose populations need them most.
The group says its influence on the vaccines market so farhas led to a 37 percent decrease in the cost for a GAVI-eligiblecountry to vaccinate a child with pentavalent, pneumococcal androtavirus vaccines since 2010.
GSK, which sells several of its vaccines - includingrotavirus, pneumococcal disease and cervical cancer shots - atreduced prices through GAVI to poor countries, said on Tuesdayit would continue to freeze those prices for a further fiveyears for countries who "graduate" from GAVI support.
By 2020, 22 countries with growing economies will become toowealthy to be eligible for GAVI's help, allowing GAVI to focuson the poorest countries and give developing economy governmentsresponsibility for immunisation.($1 = 0.7289 Euros) (Editing by Ruth Pitchford)
Glaxosmithkline (GSK)