Dr Mike Ryan, head of the World Health Organisation's (WHO) health emergencies programme, said there was "not a guarantee" a coronavirus vaccine would be found.
Even if a vaccine was developed, there would be “a lot of work to do” to roll it out across the world, he told the Global Ireland conference on Wednesday.
“The problem is going to be scaling up the production of that vaccine,” he said.
“It would be a terrible situation if we see highly vulnerable people in the developing countries not getting the vaccine, and people who would otherwise not be greatly affected by this [in wealthy countries] getting two doses.”
Dr Ryan was addressing a remote conference of Ireland’s ambassadors and diplomats, organised by the Department of Foreign Affairs, on Wednesday.
“We hope we get a vaccine, that’s not a guarantee, and even when we do there’s still a lot of work to do, and I think we can do a hell of a lot right now to drive and control this virus, and we need to really step up our efforts to do that,” he said.
Meanwhile, acting chief medical officer Ronan Glynn told the conference changes to public health measures to add "nuance" between different parts of the country in response to Covid-19 would inevitably "lead to confusion" among the public.
Dr Glynn said it was “unfortunate” that the Government’s six-month plan for Living with Covid-19 was published on Tuesday, at a time when “the trajectory of the virus was changing” in Dublin.
Opposition parties have criticised the confusion created around the Government’s new five-level plan. The entire country has been placed on Level 2, although Dublin has a number of extra conditions because of a high number of coronavirus cases in the capital.
Dr Glynn said as the country’s Covid-19 response became more nuanced and proportionate, that would “lead to confusion” among the public. He had “grown increasingly concerned” that tighter local restrictions in Dublin would lead to slippages elsewhere. “There’s always a concern if a heightened focus comes on one county, that leads to people in other counties thinking they are fine,” he said.
“We are seeing concerning trends in many counties around the country; Limerick, Waterford, Louth have all seen significant increases in cases. Dublin is in a more serious situation…The last thing we want is other counties to end up in the same situation as Dublin,” he said.
Referring to new public health measures applying to Dublin, which has seen a consistent rise in cases recently, Dr Glynn said: “To my mind the messaging is very clear, quite simply we don’t want you to mix with any more than one other household.
“We’re asking people, and this is the nuance, this is the proportionality, if possible to avoid travelling outside of Dublin for the coming weeks,” he said.
As part of the Government's medium-term plan for the pandemic, a new oversight committee has been set up to filter recommendations made by the National Public Health Emergency Team (NPHET) to the Cabinet.
The new committee, to be chaired by secretary general to the Government Martin Fraser, aims to balance NPHET’s public health advice with other economic and social implications.
Dr Glynn said there was “regularly a conflict” over public health advice, and while NPHET made recommendations it was up to the Cabinet to take decisions.
“The plan and the structures that have been put in place are an effort to rebalance, and to view the public health in combination with some other considerations,” he said.
“That said, from my perspective as we face into the coming weeks, and the challenges that appear to be on the horizon, public health will be preeminent,” Dr Glynn added.
