Of all the vaccine candidates in development, Gates believes AstraZeneca is the furthest along in creating an effective vaccine that is "inexpensive and highly dispersable."
The accounts, some of which have millions of active followers, were apparently hacked in order to spread a tweet seeking bitcoin donations by referring the user to a fake website.
"We need leaders to make these hard decisions about distributing based on equity, not just on market-driven factors."
President Donald Trump announced on Tuesday a halt in US funding to the WHO, saying it had "failed in its basic duty" in allowing the pandemic to take hold.
Governments that have lacked transparency turn even more opaque, not only to the detriment of their own people but to that of all humanity.
The founder of Microsoft's take on the COVID-19 crisis
The money is intended to ensure that treatments for the virus will be available in poor countries and affordable for individuals.
Success in reducing case numbers worldwide has been largely due to intense national and regional immunisation campaigns in babies and children.