A new Covid-19 vaccine, which is undergoing clinical trials in Brazil, Mexico, Thailand and Vietnam, could change the way the world is fighting the pandemic. The vaccine, dubbed NVD-HXP-S, is the first in clinical trials to use a new molecular design that is expected to produce stronger antibodies than the current generation of vaccines. And the new vaccine is much easier to make. Existing vaccines from companies such as Pfizer and Johnson & Johnson must be manufactured in specialized factories using hard-to-find ingredients. In contrast, new vaccines can be mass-produced in chicken eggs. This is the same egg that produces billions of flu vaccines each year in factories around the world.
If NVD-HXP-S proves safe and effective, influenza vaccine makers can produce well over a billion doses annually. Low- and middle-income countries that are currently struggling to get vaccines from wealthy countries may make NVD-HXP-S themselves or get it from neighbouring countries at low cost. However, clinical trials must first establish that NVD-HXP-S actually works in humans. clinical trials will be completed in July, and the final phase will continue for several more months. But experiments with vaccinated animals have raised hopes for the vaccine’s promise.
“It’s a protective home run,” he said. Bruce Ines, PATH Center for Vaccine Innovation and Access Coordinated Development of NVD-HXP-S. The molecular structure of HexaPro, a modified version of the SARS-CoV-2 peplomer. Six important changes are shown by the red and blue spheres. Vaccines work by giving the immune system enough knowledge to help protect against the virus. Some vaccines contain the entire killed virus. Others contain only one protein from the virus. Still others contain genetic instructions that our cells can use to make viral proteins. After exposure to a virus or part of it, the immune system can learn to produce antibodies that attack it. Immune cells can also learn to recognize and destroy infected cells.
In the case of coronavirus, the best target for the immune system is the protein that coats its surface like a corona. A protein known as a spike clings to cells and then allows the virus to fuse with them.
However, simply injecting people with coronavirus spelomers is not the best way to vaccinate them. This is because the peaplomers can take the wrong shape and encourage the immune system to make the wrong antibodies.
Jason McLellan is a structural biologist at the University of Texas at Austin. His research on coronavirus spike proteins helped develop vaccines for Pfizer, Moderna, Johnson & Johnson, and Novavax.
This understanding emerged long before the Covid-19 pandemic. In 2015, another coronavirus emerged that caused deadly pneumonia called MERS. Jason McLellan, then a structural biologist at Dartmouth College of Medicine, and his colleagues set out to create a vaccine against him. They wanted to use the spike protein as a target. However, they had to take into account the fact that the ash meter is a werewolf. When the squirrel prepares to fuse with the cell, it takes on a tulip-like shape, something more like a spear.
Scientists call these two shapes the pre- and post-fusion morphologies of the spikes. Antibodies to the pre-fused shape act strongly against the coronavirus, but post-fused antibodies do not stop it. Dr. McClellan and his colleagues used standard techniques to make the MERS vaccine, but ended up with many post-fusion spikes that didn’t serve their purpose. Then they found a way to fix the protein in a tulip-like pre-fusion form. All they had to do was change two of the more than 1,000 building blocks of protein to a compound called proline.
The resulting spike, called 2P, for the two new proline molecules it contained was much more likely to take on the desired tulip shape. Researchers injected 2P spikes into mice and found the animals could easily fight MERS coronavirus infections. The team filed a patent for their modified spike, but the world ignored the invention. MERS, while deadly, is not highly contagious and has proven to be a relatively minor threat; since its first appearance, less than 1,000 people have died from MERS. in people.
However, in late 2019, the new coronavirus SARS-CoV-2 emerged and began to devastate the world. Dr. McClellan and his colleagues took action and designed a 2P spike specific to SARS-CoV-2. Within a few days, Moderna used that information to design a vaccine for Covid-19. It contained a genetic molecule called RNA with instructions for making 2P spikes.
Other companies soon followed suit, introducing 2P spikes into their vaccine designs and initiating clinical trials. All three vaccines approved to date in the US, including Johnson & Johnson, Moderna, and Pfizer-BioNTech, use 2P spikes. Other vaccine manufacturers use it as well.
