With new variants and sub-variants of COVID evolving ever faster, each eliminating the effectiveness of leading vaccines, the hunt is on for a new type of vaccine that works equally well on current and future forms of the novel coronavirus.
Now researchers at the National Institutes of Health in Maryland believe they have found a new approach to vaccine design that could lead to a long-lasting vaccine. As a bonus, it may also work on other coronaviruses, not just the SARS-CoV-2 virus that causes COVID.
The NIH team reported their findings in a peer-reviewed study published in the journal Cell Host & Microbe earlier this month.
Key to the NIH’s potential vaccine design is a part of the virus called the “spinal helix.” It’s a spiral-shaped structure inside the spike protein, the part of the virus that helps it grab onto and infect our cells.
Many current vaccines target the spike protein. But none of them specifically target the spinal helix. And yet, there are good reasons to focus on this part of the pathogen. While many regions of the spike protein tend to change greatly as the virus mutates, the backbone helix It does not suit.
This gives scientists “hope that an antibody that targets this region will be more durable and broadly effective,” Joshua Tan, the NIH team’s lead scientist, told The Daily Beast.
Vaccines that target and “bind,” so to speak, the receptor-binding domain region of the spike protein may lose their effectiveness if the virus evolves within that region. The great thing about the spinal helix, from an immunological point of view, is that it doesn’t mutate. At least, it hasn’t mutated Yetthree years after the COVID pandemic.
Thus, a vaccine that binds the backbone helix in SARS-CoV-2 should last for a long time. And it should also work on all the other coronaviruses that also involve the spinal cord—and there are dozens of them, including several like SARS-CoV-1 and MERS that have already made the jump from animal populations and caused outbreaks in humans.
To test their hypothesis, NIH researchers extracted antibodies from 19 recovered patients with COVID and tested them in samples of five different coronaviruses, including SARS-CoV-2, SARS-CoV-1 and MERS. Of the 55 different antibodies, most have zeroed in on parts of the virus that tend to mutate a lot. Just 11 targeted the spinal helix.
But those 11 that followed the spinal helix performed better, on average, on four of the coronaviruses. (A fifth virus, HCoV-NL63, elicited all antibodies.) The NIH team isolated the best spinal helix antibody, COV89-22, and also tested it in hamsters infected with the latest subvariants of the variant Omicron of COVID. “Hamsters treated with COV89-22 showed a reduced pathology score,” the team found.
The results are promising. “These findings identify a class of … highly neutralizing antibodies [coronaviruses] targeting the stem helix,” the researchers wrote.
Don’t break out the champagne just yet. “Although these data are useful for vaccine design, we have not performed vaccination experiments in this study and therefore cannot draw definitive conclusions about the efficacy of stem-helix-based vaccines,” the NIH team cautioned.
It’s one thing to test some antibodies in hamsters. It’s another to develop, test, and get approval for an entirely new class of vaccines. “It’s really hard, and most things that start out as good ideas fail for one reason or another,” James Lawler, an infectious disease specialist at the University of Nebraska Medical Center, told The Daily Beast.
And while backbone-helix antibodies seem to be largely effective, it is not clear how they stack up against antibodies that are more specific. In other words, a spinal helix jab may work against a bunch of different but related viruses, but work less well against any one virus than a jab that is specifically tailored for that virus. “Further experiments need to be done to assess whether they will be sufficiently protective in humans,” Tan said of the backbone-helix antibodies.
A lot of work needs to be done before a spine vaccine is available at the corner drugstore. And there are many things that could derail this job. Additional studies could contradict the NIH team’s results. The new vaccine design may not work as well in humans as it does in hamsters.
The new piercing could also prove unsafe, impractical to produce, or too expensive for widespread distribution. Barton Haynes, an immunologist at Duke University, told the Daily Beast that he reviewed spinal cord vaccine plans last year and concluded that they would be too costly to warrant significant investment. The main problem, he said, is that the spindle helix antibodies are less potent and “difficult to induce” than their B-cell parent.
The harder the pharmaceutical industry has to work to produce a vaccine, and the more vaccine has to be packed into a single dose to compensate for the lower potency, the less cost-effective a vaccine becomes to mass produce.
Maybe a spinal tap is in our future. Or maybe not. Either way, it’s encouraging that scientists are making incremental progress toward a more universal coronavirus vaccine. One that could work for many years on a wide range of related viruses.
COVID isn’t going anywhere. And with each mutation, it risks becoming unrecognizable to current vaccines. What we need is a vaccine that is resistant to mutations.