Remember whack-a-mole, the arcade game where a plastic mole pops its head up and you whack it with a mallet?
It's a game scientists are comparing to the fight against COVID-19: No sooner has one mole, or variant, been whacked by vaccines than another appears.
We are at a stage where current vaccines, while reducing severe disease and death, are no longer as good at stopping widespread infection.
We're waiting to whack it with a new Omicron-specific jab that we will get later this year. However, when it arrives, potentially in the spring, the virus could have mutated further.
So, when will we get ahead of the virus and how far away are we from having a universal vaccine, one that will target all past and future COVID-19 variants and sub-variants?
According to scientists, such as viral immunologist David Martinez, the early signs in initial trials are promising.
"One of the main avenues of research that we've been actively exploring over the last year and a half or so, [are] next-generation, broad-sweep, universal vaccines that could not only deal with existing SARS-CoV-2 variants, but could perhaps ward off a future emergence event of a [different] coronavirus," Dr Martinez told the ABC News Daily podcast.
Dr Martinez — from the Gilling School of Global Public Health at the University of North Carolina — is working on a universal vaccine so we can move on from the whack-a-mole approach.
He has already been evaluating the efficacy of the vaccine in animals, including mice.
"What we've actually demonstrated by one of our vaccine concepts is a vaccine that could not only protect against SARS-CoV-2 and its variants — at least even against Omicron, that we've tested and shown efficacy against — but also against the original SARS."
Funding stands in the way
SARS first emerged in 2003 in Southern China, killing 774 People. Almost a decade later, in 2012, MERS — another coronavirus — was found in the Middle East, with just under 900 associated deaths.
"Now we have a virus that needs no introduction," Dr Martinez said of COVID-19.
Dr Martinez points out there are seven known coronaviruses that infect humans, four of which really just cause the common cold. The other three — SARS, MERS and COVID-19 — cause severe disease.
"In my opinion, even if a vaccine didn't necessarily cover all of the coronaviruses, what could perhaps be achievable would be a vaccine that could cover maybe half, and then another vaccine to cover the other [more deadly] half."
The main barrier to the vaccines proceeding to human trials, according to Dr Martinez, is funding.
"So [we need] something similar to what we saw with Operation Warp Speed in the United States, with the investment into five different vaccine strategies that ended up being successful," he said.
"I think something like that needs to happen for these next-generation, universal coronavirus vaccines.
"And, ultimately, I think with any sort of investment, you really have to diversify your efforts because we, ultimately, don't know which effort is going to be the most successful in the end."
Operation Warp Speed received $US18 billion ($AU26 billion) in funding by October 2020.
Dr Martinez noted scientists are also working in parallel on antiviral medicines that could be taken to treat recurrent infections.
He is optimistic a universal vaccine will be ultimately approved but is concerned even once that does happen there remain major barriers.
"Even if we are able to develop something like this at that scale, you still have to convince people to take the shot, and we — at least in the United States — have sort of struggled to convince a large enough number of people to get vaccinated in the first place."
