A vaccine breakthrough could finally bring COVID to its knees
WITH new COVID variants and sub-variants it develops faster and faster, and each one reduces the effectiveness of leadership vaccinesthe search is underway for a new type of vaccine — one that works equally well against current and future forms of the new coronavirus.
Now researchers at the National Institutes of Health in Maryland think they’ve found a new approach to vaccine design that could lead to a long-lasting shot. As a bonus, it might work too other coronavirusesand not just the SARS-CoV-2 virus that causes COVID-19.
The NIH team reported their findings in a peer-reviewed study which appeared in the magazine Cellular host and microbe earlier this month.
The key to NIH’s potential vaccine design is a part of the virus called the “backbone helix.” It’s a coiled-coil structure inside the spike protein, the part of the virus that helps it capture and infect our cells.
Many current vaccines target the spike protein. But none of them specifically target the spiral of the spine. Still, there are good reasons to focus on that part of the pathogen. While many regions of the spike protein change frequently as the virus mutates, the backbone helix does not work.
This gives scientists “hope that an antibody that targets this region will be more durable and broadly effective,” Joshua Tan, lead scientist on the NIH team, told The Daily Beast.
Vaccines that target and “bind” to, say, the region of the spike protein receptor binding domain could lose efficacy if the virus evolves within that region. The great thing about the backbone helix, from an immunological standpoint, is that it doesn’t mutate. At least he didn’t mutate morethree years after the COVID pandemic.
Thus, a vaccine that binds the backbone helix in SARS-CoV-2 should last a long time. It should also work against all the other coronaviruses that also involve the spine spiral—and there are dozens, including several like SARS-CoV-1 and MERS that have already made the jump from animal populations to cause outbreaks in humans.
To test their hypothesis, NIH researchers extracted antibodies from 19 patients who had recovered from COVID and tested them on samples from five different coronaviruses, including SARS-CoV-2, SARS-CoV-1 and MERS. Of the 55 different antibodies, most focused on parts of the virus that tend to mutate. Only 11 targeted the spinal cord.
But those 11 who went after the spinal helix worked better, on average, on four coronaviruses. (A fifth virus, HCoV-NL63, removed all antibodies.) The NIH team isolated the best antibody for the spinal cord, COV89-22, and also tested it in hamsters infected with the latest Omicron subvariant of the COVID variant. “Hamsters treated with COV89-22 showed a reduced pathology score,” the team found.
The results are promising. “These findings identify a class of… broadly neutralizing antibodies [coronaviruses] by targeting the stem helix,” the researchers wrote.
Don’t break out the champagne yet. “Although these data are useful for vaccine design, we did not conduct vaccination trials in this study and therefore cannot draw any definitive conclusions regarding the efficacy of stem-helix-based vaccines,” the NIH team cautioned.
It’s one thing to test a few antibodies on hamsters. It is another to develop, conduct trials and obtain approval for an entirely new class of vaccine. “It’s really hard and most things that start out as good ideas fail for one reason or another,” James Lawler, an infectious disease expert at the University of Nebraska Medical Center, told The Daily Beast.
And while antibodies appear to be spine-helix wide effective, it is not clear how they stack up against antibodies that are more specific. In other words, a spine-helix jab can work against a bunch of different but related viruses, but perform worse against any one virus than a jab specifically tailored for that virus. “Further trials are needed to assess whether it will be protective enough in humans,” Tan said of the anti-spinal cord antibodies.
There is a lot of work to be done before the spine-helix vaccine is available at the corner drug store. And there are many things that could disrupt that work. 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 sting could also prove to be unsafe, impractical to manufacture, or too expensive for widespread distribution. Barton Haynes, an immunologist at Duke University, told The Daily Beast that he looked at the spine-helix vaccine design last year and concluded that it would be too expensive to justify the large investment. The main problem, he said, is that spine-helix antibodies are less potent and “difficult to induce” from their parent B cells.
The more the pharmaceutical industry has to work to produce a vaccine and the more vaccine it has to pack into a single dose to compensate for the lower potency, the less cost effective the vaccine becomes for mass production.
Maybe a spine-helix stab is in our future. Or maybe not. In any case, it is encouraging that scientists are gradually making progress towards it more universal vaccine against coronavirus. One that could work for many years on a wide range of related viruses.
COVID for one is not going anywhere. And with each mutation, there is a danger that it will become unrecognizable to current vaccines. What we need is a vaccine that is resistant to mutations.