Bill Gates has been funding the production of a coronavirus vaccine, focusing his philanthropic work in eradicating the ongoing coronavirus pandemic.

Speaking to CNN’s Fareed Zakaria, Gates said, “If everything went perfectly, we’d be in scale manufacturing within a year. It could be as long as two years.”

The co-founder of Microsoft Corporation said the production of vaccine would probably not start in September, according to sources.

Gates said, “Dr. Fauci and I have been fairly consistent to say 18 months to create expectations that are not too high.”

Dr. Anthony Fauci, who is the head of the National Institute of Allergy and Infectious Diseases (NIAID), is a member of the White House Coronavirus Task Force.

In the United States, the availability of coronavirus testing has been a sore spot. On Saturday, President Donald Trump tweeted that the nation “just passed 5 million Tests, far more than any other country.”

Gates said, “Just looking at raw numbers misses the true picture.”

“This focus on the number of tests understates the cacophony and the mistakes we’ve made in the testing system,” Gates added. “The wrong people are being tested, and any time you don’t get results in less than 24 hours, the value of the test is dramatically reduced.”

Gates said his best-case scenario for a phased reopening of the economy is to “pick the high-value activities like school, manufacturing, and construction, and figure out a way to do those with masks and distancing.”

“If we can figure out how to do K-through-12 in the fall, that would be good,” he added. “It will probably be in August where we know what’s the protocol, how many schools are opening up, and we won’t really know enough until pretty close to the start.”

The philanthropist also cautioned that acting prematurely by reopening businesses and generating an exponential growth in coronavirus cases “will be seeding other parts of the country.”

Previously, Gates told the Financial Times that his Bill & Melinda Gates Foundation would give total attention to COVID-19, with an endowment exceeding $40 billion. The foundation contributed nearly $250 million to help combat the coronavirus pandemic so far.

Gates supported the World Health Organization (WHO) and defended it against accusations from Trump that the organization had mishandled the coronavirus response.

He told the Financial Times, “WHO is clearly very, very important and should actually get extra support to perform their role during this epidemic.” The article originally appeared in Fortune.