While it appears that only a COVID-19 vaccine may take us back to normal, its development may take at least nine months to two years, the billionaire philanthropist has said.

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Even though several drugs are also being tested to treat COVID-19, the philanthropist believes the perfect drug that might help the world go back to the way things were in December before the coronavirus pandemic is far from sight. "Most of the drug candidates right now are nowhere near that powerful. They could save a lot of lives, but they aren't enough to get us back to normal," the Microsoft co-founder wrote in his GatesNotes blog on April 30.

In the absence of an "almost perfect drug to treat COVID-19", it becomes imperative that every person on the planet gets vaccinated against coronavirus. "Realistically, if we're going to return to normal, we need to develop a safe, effective vaccine. We need to make billions of doses, we need to get them out to every part of the world, and we need all of this to happen as quickly as possible," he said.

While vaccine development usually takes around five years, the philanthropist believes that scientists may come up with a coronavirus vaccine within 9 months to two years time. "As of April 9, there are 115 different COVID-19 vaccine candidates in the development pipeline. I think that eight to ten of those look particularly promising," said the philanthropist.

The Bill and Melinda Gates Foundation is funding several efforts to find a solution to the COVID-19 pandemic. The Microsoft co-founder explained that safety and efficacy are the two most important goals for every vaccine. Some minor side effects, like a mild fever or injection site pain, are generally acceptable, and all vaccines do not have 100 percent efficacy.

"For example, this year's flu vaccine is around 45 percent effective," he said. "I suspect a vaccine that is at least 70 percent effective will be enough to stop the (COVID-19) outbreak. A 60 percent effective vaccine is useable, but we might still see some localised outbreaks. Anything under 60 percent is unlikely to create enough herd immunity to stop the virus," the philanthropist noted. To stop the pandemic, the world will need to manufacture and distribute at least 7 billion doses (or possibly 14 billion, if it's a multi-dose vaccine) of the vaccine, he added.