* AstraZeneca says it has deals for 400 million doses
overall

* World powers scramble for vaccine supplies

* Britain has already secured 100 million doses
(Adds detail from HHS statement)

By Aakash B, Guy Faulconbridge and Kate Holton

BENGALURU/LONDON, May 21 (Reuters) – The United States has
secured almost a third of the first 1 billion doses planned for
AstraZeneca’s experimental COVID-19 vaccine by pledging up to
$1.2 billion, as world powers scramble for medicines to get
their economies back to work.

While not yet proven to be effective against the
coronavirus, vaccines are seen by world leaders as the only real
way to restart their stalled economies, and even to get an edge
over global competitors.

After President Donald Trump demanded a vaccine, the U.S.
Department of Health and Human Services (HHS) agreed to provide
up to $1.2 billion to accelerate British drugmaker AstraZeneca’s
vaccine development and secure 300 million doses for the
United States.

“This contract with AstraZeneca is a major milestone in
Operation Warp Speed’s work toward a safe, effective, widely
available vaccine by 2021,” U.S. Health Secretary Alex Azar
said. The first doses could be available in the United States as
early as October, according to a statement from HHS.

The vaccine, previously known as ChAdOx1 nCoV-19 and now as
AZD1222, was developed by the University of Oxford and licensed
to AstraZeneca. Immunity to the new coronavirus is uncertain and
so the use of vaccines is unclear.

The U.S. deal allows a late-stage, or Phase III, clinical
trial of the vaccine with 30,000 people in the United States.

Cambridge, England-based AstraZeneca said it had concluded
agreements for at least 400 million doses of the vaccine and
secured manufacturing capacity for 1 billion doses, with first
deliveries due to begin in September.

Now the most valuable company on Britain’s blue-chip FTSE
100 Index, AstraZeneca has already agreed to deliver 100 million
doses to people in Britain, with 30 million as soon as
September. Ministers have promised Britain will get first access
to the vaccine.

VACCINE SCRAMBLE

With leaders across the world surveying some of the worst
economic destruction since at least World War Two and the deaths
of more than 327,000 people, many are scrambling for a vaccine.

The U.S. government has struck deals to support vaccine
development with Johnson & Johnson (J&J), Moderna
and Sanofi, sparking fears the richest
countries will be able to protect their citizens first.

Sanofi’s chief angered the French government earlier this
month when he said vaccine doses produced in the United States
could go to U.S. patients first, given the country had supported
the research financially.

“We have a lot of things happening on the vaccine front or
the therapeutic front,” Trump told reporters at the White House
when asked about the AstraZenca announcement. “You’re going to
have a lot of big announcements over the next week or two” on
therapeutics.

Trump, during a Thursday visit to a Ford Motor Co
plant in Michigan, said the U.S. military is “in gear so we can
give out 150 to 250 million shots quickly.”

AstraZeneca said it was in talks with governments and
partners around the world – such as the Serum Institute of India
– to increase access and production and is speaking to various
organisations on fair allocation and distribution.

“We would like to thank the U.S. and UK governments for
their substantial support to accelerate the development and
production of the vaccine,” AstraZeneca Chief Executive Pascal
Soriot said.

The Serum Institute of India, the world’s largest maker of
vaccines by volume, has dedicated one of its facilities with a
capacity to produce up to 400 million doses annually to
producing the Oxford vaccine.

“We are scaling up on a conservative basis of about 4 to 5
million doses a month to begin with,” Chief Executive Adar
Poonawalla told Reuters, adding the company was in discussions
with AstraZeneca.

COVID-19 PROTECTION?

A Phase I/II clinical trial of AZD1222 began last month to
assess safety, immunogenicity and efficacy in over 1,000 healthy
volunteers aged 18 to 55 across several trial centres in
southern England. Data from the trial is expected shortly.

There are currently no approved treatments or vaccines for
COVID-19.

Governments, drugmakers and researchers are working on
around 100 programmes. Experts are predicting a safe, effective
means of preventing the disease could take 12 to 18 months to
develop.

Only a handful of the vaccines in development have advanced
to human trials, an indicator of safety and efficacy, and the
stage at which most fail.

“AstraZeneca recognises that the vaccine may not work but
is committed to progressing the clinical program with speed and
scaling up manufacturing at risk,” it said.

Other drugmakers including Pfizer Inc, J&J and
Sanofi are in various stages of vaccine development.

U.S.-based Inovio Pharmaceuticals said Wednesday its
experimental vaccine produced protective antibodies and immune
system responses in mice and guinea pigs.

And Moderna this week released positive data for its
potential vaccine, which it said produced protective antibodies
in a small group of healthy volunteers.

(Reporting by Aakash Jagadeesh Babu in Bengaluru, Ludwig Burger
in Frankfurt and Zeba Siddiqui in New Delhi; writing by Guy
Faulconbridge; editing by Alexander Smith, Jan Harvey, Mark
Potter, Jonathan Oatis and Leslie Adler)