Coronavirus: From a second wave to the hunt for a vaccine - what the future may hold for COVID-19

It is the question everyone wants to know the answer to: when will this pandemic end, and what will our future look like?

It is the question everyone wants to know the answer to: when will this pandemic end, and what will our future look like?

Back in March, before the UK's coronavirus lockdown began and when the country had reported two deaths of people with COVID-19, Sky News asked several epidemiologists what the best and worst outcomes could be.

Four months down the line, one of those specialists - infectious disease expert Professor Mark Jit - has again spoken about what we can expect in the future and whether we will ever be able to eradicate the disease.

Will there be a second wave in the UK?

Professor Jit, from the London School of Hygiene and Tropical Medicine, said the likelihood of a second wave will depend on how effectively the country is able to put measures in place to stop the spread.

He said it is "almost guaranteed" we will see larger localised outbreaks like the one seen in Leicester - the first city to enter a local lockdown - "because there will be cases that get through the net".

"In all the countries where the first wave has well and truly ended - in China, in South Korea, all these countries - there have been localised outbreaks, so we can't avoid that," he told Sky News.

But the possibility of a large national second wave is something that could be avoided with the right response.

Professor Jit said: "I think our ability to avert this from becoming a big national second wave of maybe the size that the first wave has been will depend on how good the reaction is, in terms of detecting the cases as soon as possible, following up in terms of testing and contact tracing, and being able to have localised lockdowns."

Will we find a vaccine?

Professor Jit is optimistic about this, given that "a lot of attention and a lot of money" is being put into vaccine trials.

However, he said it is "hard to say" for sure whether we will find one because the trials are still in the early stages, but suspects that "out of the hundred or more candidates... some of them will be successful".

He added: "If we are very fortunate and some of the leading candidates are successful, then we could have a vaccine within a year or two years. If we're less fortunate... then we will have to wait and see."

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The other question, he said, is what we mean by successful. In an ideal world, we would find a vaccine that works on everybody and gives them lifetime protection.

But it may be the case that we have a vaccine that only works for some people - for example, it might not work for the older population - or people may need to have vaccinations every few years.

Few vaccines are 100% effective in all people who get them, but the World Health Organisation (WHO) estimates that vaccines can prevent up to three million deaths per year even so.

A potential vaccine might also only be able to protect people from becoming more seriously ill from coronavirus, rather than preventing them from catching it.

Professor Jit pointed out that some vaccines we have for other diseases work like this.

Will countries be willing to share a vaccine?

There are some fears that countries which develop a vaccine may be unwilling to share it.

These worries were stoked further when the US bought up most of the world's supply of the drug remdesivir, which is shown to reduce time in hospital for some coronavirus patients.

Professor Jit said that mechanisms should be put in place now to "ensure that the vaccine gets to the people who most need it - wherever in the world they're living".

For example, the University of Oxford team developing a vaccine has reached a licensing agreement to supply one billion doses for low and middle-income countries.

Professor Jit said this not only benefits people across the world, but also the countries supplying the vaccine.

He told Sky News: "If there are huge epidemics still going on in other parts of the world then we can never let our guard down in the UK. This virus will not be over anywhere until it's over everywhere."

Will we be able to eliminate the virus?

"It's possible," said Professor Jit, who has contributed to a report on the feasibility of controlling outbreaks.

"But first of all we would have to have an effective vaccine.

"And second of all, we would have to have a massive global endeavour."

Professor Jit, who also works in the modelling and economics unit of Public Health England, pointed to viruses we have eradicated in the past - including smallpox, which has a higher infection rate than COVID-19.

"That was really the whole world coming together saying we really want to get rid of this virus and we did," he said.

The most important thing, the professor said, is making sure that countries are co-ordinating their responses.

What is the worst case scenario?

It's a sobering thought, but Professor Jit says we already seem to be heading for the worst possible outcome he theorised back in March.

He told Sky News: "Unfortunately, we are already heading towards what I would have said several months ago is our worst case scenario.

"If things don't change, we are going to be in the worst case scenario where we don't have this under control, we have big outbreaks of it every year."

On comparing COVID-19 to flu, as many did at the beginning of the pandemic, he said: "We have seasonal influenza every year, but except for people who are extremely vulnerable, most people will recover from flu.

"We're finding with COVID, a large proportion of people get hospitalised. Many people have long-term effects. The proportion of people who actually die from this is actually much greater than for flu.

"So if this becomes something that we see in recurrent waves every year, this will really be devastating - both for people's lives and economies."

What is the best case scenario?

In an ideal scenario, we could quickly develop a successful vaccine and find effective treatments, Professor Jit said.

Testing would improve to become more accurate and with faster results, and those who have already been infected would have long-lasting immunity.

"If all of these come together... We're really going to make an effort to eliminate this virus - or to at least control it as much as possible," he said.

Even if the virus is not completely eradicated, it could become a much lesser problem with an effective vaccine, contact tracing and measures in place to stop outbreaks.

"But that is the very best case scenario, which would require both the technologies being developed and countries around the world working together to control the virus," the professor said.

He added: "Now that we've seen what's happened, we also know a bit more about the virus, we've seen how the response has been complicated, I think I'm more pessimistic than before.

"But I'm still putting hope in human beings around the world and our ability to solve this problem."