A vaccine for Covid-19 will not be ready until the end of next year, according to Dale Fisher, chair of the World Health Organization (WHO) Global Outbreak Alert and Response Network.
That timeline would be a "very reasonable" expectation because of the necessary Phase 2 and 3 trials of any vaccine to guarantee both safety and efficacy, Fisher explained. There would also need to be a ramp up in production and distribution, as well as actually administering the vaccine, he said.
Fisher said "we are currently on target" for a vaccine in 2021 with five Phase 1 studies currently underway.
"We've always felt that by about April, May, we would be in Phase 1 studies, so this means a potential vaccine has been invented if you like; we're now trying it on individuals, basically to see if it's safe," Fisher told CNBC's "Street Signs Asia" on Monday.
The current trials would allow "early collection of data" to assess whether the potential vaccine "actually works," before larger trials on safety and efficacy could be carried out, said Fisher, who is also a senior consultant at the infectious disease division at the National University Hospital in Singapore.
Fisher also said President Donald Trump's comments on Sunday — that he was confident a coronavirus vaccine would be developed by the end of 2020 — were "a bit premature."
Meanwhile, Severin Schwan, CEO of pharmaceutical giant Roche, also expressed some skepticism over the president's proposed time frame, saying the end of this year was "certainly an ambitious goal."
"I have no doubt that as so many companies are working on a vaccine in parallel, and as we see such great collaboration with regulators including the FDA, we can actually speed up the approval of vaccines," he told CNBC's "Squawk Box Europe" on Monday.
"But still, typically it would take years to develop a new medicine. Most experts agree that it will take at least 12 to 18 months until we see a vaccine which is available in the necessary quantities for patients."
The preliminary results of clinical trials for Gilead Sciences' antiviral remdesivir have been promising, indicating it could shorten the recovery time for hospitalized coronavirus patients. The U.S. Food and Drug Administration has since granted emergency use authorization for the drug.
Despite very positive information on remdesivir, it is still far from being the proven wonder drug we would love to see, according to Fisher.
But ultimately, the best defense against Covid-19 would be a vaccine which would "get immunity in the public to stop this," Fisher said. Natural herd immunity was not the way to go, he said. Herd immunity refers to a situation where enough people in a population have become immune to a disease such that it effectively stops the disease from spreading.
Until a vaccine is ready, each individual has to understand the role they have to play in public health, Fisher said. He emphasized that there needs to be continual "messaging" on that.
Instead of just relying on contact tracing measures, simple efforts including social distancing, presenting oneself at hospitals and not heading out when sick were "so important" and necessary, Fisher said.