New York,  The Bill & Melinda Gates Foundation has committed additional $150 million in the global fight against COVID-19, raising its total funding to $250 million.

The foundation's new $150 million commitment announced late on Wednesday will fund the development of diagnostics, therapeutics, and vaccines, as well as new efforts to provide partners in Africa and South Asia with resources to scale their COVID-19 detection, treatment, and isolation efforts.

In announcing the funding, the foundation called on world leaders to unite in a global response to COVID-19 to ensure equitable access to diagnostics, treatments, and vaccines.

"COVID-19 doesn't obey border laws. Even if most countries succeed in slowing the disease over the next few months, the virus could return if the pandemic remains severe enough elsewhere," Gates Foundation co-chair Bill Gates said in a statement.

"The world community must understand that so long as COVID-19 is somewhere, we need to act as if it were everywhere. Beating this pandemic will require an unprecedented level of international funding and cooperation."

The foundation will also leverage a portion of its $2.5 billion Strategic Investment Fund, which uses a suite of financial tools to address market failures and incentivise private enterprise to develop affordable and accessible health products.

These funds, which can include equity investments, loans, and volume guarantees, will be used to help health systems in low- and middle-income countries (LMICs) facilitate the rapid procurement of personal protective equipment for health care workers, COVID-19 diagnostics, oxygen therapeutics, and other essential medical supplies.

Any financial returns generated by the Strategic Investment Fund are re-invested in Gates Foundation philanthropic programmes.

The foundation in February announced $100 million to support the global response against COVID-19.