Helping design and evaluate strategies to enhance disease surveillance systems, improve vaccine coverage and data quality, and ultimately reduce the presence of VPDs.

It is also used to validate reported vaccine coverage (for example, from administrative reports) and is expected to estimate vaccine coverage within 10 percent.

GAVI has already allocated more than $800 million to help 52 poor countries expand their vaccine coverage.

The money raised would go to increase vaccine coverage through the vaccine alliance and, if the facility expanded, to fight AIDS.

Yet vaccine coverage is dropping in Africa.

Lack of complete vaccine coverage increases the risk of disease for the entire population, including those who have been vaccinated, because it reduces herd immunity.

That illness is a threat to New York City unless vaccine coverage is 100 percent, which it never is.

The problem with measles is its high transmissibility; to interrupt transmission, a vaccine coverage of 95 per cent is needed.

It also helps the poorest nations extend their vaccine coverage, and through Unicef buys them new vaccines.

But in many nations vaccine coverage is dropping because the money is not there.