Scientists in the US have developed what they're calling a potential "ultrapotent" vaccine against COVID-19.
The vaccine, designed on a computer, produces 10 times as many antibodies as typically found in a recovered patient and other vaccines, at least in tests on mice and monkeys.
More than 1.2 million people have been killed this year by the virus, and economies battered as nations go into lockdown to stop its spread.
There's growing evidence infection with the virus doesn't offer much in the way of immunity, unlike most viral diseases, meaning a vaccine might be the only way to get the pandemic under control. Dozens of efforts are underway, some in human trials, but it's widely expected the first proven safe and made available might not offer the strongest protection in the long-term.
Scientists at the University of Washington have developed one using a custom-made protein nanoparticle which resembles the virus which causes COVID-19, SARS-CoV-2.
"We took a very small piece of a protein from the coronavirus and we decorated our nanoparticle with it," said research scientist Brooke Fiala.
"When we gave the nanoparticle vaccine to the mice, we saw a dramatic increase in antibody production. The ability of the mouse blood to neutralise the virus was substantially greater with the nanoparticle vaccine."
The virus gets into human cells using what's known as the spike protein - the pointy bits you see in pictures of the virus. Alexandra Walls, lead author of the study outlining how the new vaccine works, said while other vaccines are focusing on mimicking the entire spike protein, theirs uses "just to use one specific piece of the spike protein to really focus the immune response".
"We wanted to train our immune system on just this piece to have the strongest response possible."
And it seems to work, producing 10 times more neutralising antibodies in mice than vaccines based on using the entire spike protein, at doses six times lower. It also generated a strong B-cell response, "which can be critical for immune memory and a durable vaccine effect" the scientists say.
It also seemed to target various spots on the virus spike protein, so should work even if part of it mutates to avoid other vaccines.
"We've seen amazing results in mice so we moved into non-human primates, and we're still seeing just incredible results," said Walls. "Everything worked as we kind of dreamed."
Experts in medical journal The Lancet earlier this year said reaching herd immunity without a vaccine is "not only highly unethical, but also unachievable". Walls said she's been working on nanoparticle coronavirus vaccines for five years now.
"Until earlier this year no one else seemed to know or care much about them - but obviously that's all changed... This will not be the last pandemic - I can tell you that with certainty... so pushes like these to make vaccine platforms like our nanoparticle will only serve to benefit us in the future."
Their paper was published in journal Cell this week.
