Second generation COVID vaccine is now available

Six months ago, the Northern Hemisphere was still fighting the first wave of the coronavirus pandemic, so in late-stage clinical trials all eyes turned to the COVID-19 vaccine. A year after the first pandemic, three COVID vaccines received emergency permits from the United States or the United Kingdom and other countries. The two vaccines, each developed by Pfizer and BioNTech and Moderna, both employ a new genetic technology known as mRNA. And the third is a conventional vaccine developed by the University of Oxford and AstraZeneca that delivers the DNA of the components of SARS-CoV-2, a virus that uses the chimpanzee virus to cause COVID. (Russia, China and India have their own vaccines, but they are not widely approved in other countries except in some countries.)

But, impressively, experts say that these vaccines alone are likely not enough to end a pandemic. Fortunately, there are hundreds of other COVID vaccines under development, many with new mechanisms of action that could prove to be effective, inexpensive and easy to distribute.

“The virus has changed and we believe that the currently approved vaccines are not as effective as we think.” Danny Altman, An immunologist at Imperial College London. SARS-CoV-2 has already evolved several new variants. First identified in the UK and South Africa, More contagious (but less deadly, at least for now).

Gregory PolandAs a Mayo Clinic vaccine scholar, we agree that it is too early to think we will overcome the virus. He points out that the coronavirus vaccine has never been introduced into a public vaccination program. And mRNA vaccines such as Pfizer and Moderna have been touted by many as the future of vaccine science and have never been put on the market. “We don’t know what we don’t know. We don’t know what surprises we’ll find in a virus we’ve only known for a year,” said Poland, co-author. Extensive review of COVID-19 vaccine candidates At Lancet last October. “And there’s a lot we’ve been involved in in the history of vaccine science that I’ve been involved in for 40 years. Thought We knew. “

What if someone is vaccinated but gets infected with COVID anyway? Will they suffer from a worse case of illness, a phenomenon known as antibody-dependent enhancement? Or, in less dramatic scenarios, would the vaccine prevent the vaccinated individual from getting sick, but prevent it from infecting others? The latter can actually exacerbate the pandemic if the vaccinated individual is considered to be a safe and asymptomatic carrier. In addition, as people around the world show a wide range of innate immunity to the virus, there may be similar diversity in vaccine responses. “There are a lot of booby traps that may be waiting for you,” says Poland.

In addition, the Moderna and Pfizer vaccines have logistical issues that make them difficult to deploy globally. Pfizer vaccines should be stored in a freezer at –70 degrees Celsius, below the average temperature in Antarctica, and cost thousands of dollars. Moderna can be stored at -15 ° C, but because it requires a freezer, it is unlikely to reach the rural areas of India and Africa or the poor and dense areas of South America. As long as the vaccine is fragile, expensive and difficult to distribute, the pandemic will continue.

But according to Altman, the most important issue to date is “durability.” That is, the period during which people maintain immunity after vaccination. If the vaccine immunizes for only a few months instead of years, then there is little progress in 6 months. By that time, we may face more toxic forms of swirling diseases around the world.

Fortunately, however, “second generation” vaccines are being developed by researchers, many of whom are researching new technologies. “We have the embarrassment of wealth,” says Altman. “One of the things that most people certainly don’t appreciate is that in Backburner, the field of vaccine science has gained momentum over the last 15 years, developing a variety of incredibly sophisticated strategies. That is. “

There is Almost 240 New vaccine candidates under development, waiting for their moments on the wings. Here are some of the most possible.

Self-amplified RNA (Imperial College London)

Similar to the approved mRNA vaccine, it inserts genetic material from the virus directly into human cells and spurs the body to produce the famous “peplomer” protein that covers the surface of SARS-CoV-2. .. And like the mRNA vaccine, Imperial College London Design Because it delivers only the genetic material, not the actual virus, it is unlikely to exacerbate the disease if infected after vaccination. The twist of this vaccine is that it is being modified to turn the body’s own cells into factories and constantly release the spiked proteins on its own. So you don’t need a booster shot. In addition, it has been reported that such “self-amplifying” RNA can be produced in large quantities at a fraction of the cost. “I’m very excited about that method. [this approach] It could be like a Pfizer or Moderna vaccine, but it could be even better, “says Altman, who was not directly involved in the development of this vaccine.

Protein subunit (Novavax)

Researchers at Novavax, a Maryland-based startup, are focused on providing the actual peplomer itself (rather than the entire virus or genetic material). They created a vaccine by manipulating moth cells Unleash spike proteins in bioreactors at low cost. In addition, this vaccine can be kept at the normal refrigeration temperature of 2-8 ° C, making distribution much more practical. The secret of this approach is to add an “adjuvant” (an additive that “sucks up” the reaction of the immune system) made from saponin, a compound derived from the bark of the Chilean Kiraya tree. “Engineering protein technology has been tested and proven in the past. It takes a little longer to produce than RNA,” explains Gregory Glenn, Head of Research and Development at Novavax.

Designed protein nanoparticles (University of Washington Institute for Protein Design)

Like Novavax, researchers at the University of Washington have chosen to deliver the protein from SARS-CoV-2 as the weapon of choice. However, instead of injecting the entire peplomer, they focused on the viral “Achilles tendon,” the receptor-binding domain (RBD), which is the portion of the peaplomer that fuses directly with human cells. Neil King, a biochemist at the University’s Institute for Protein Design, created a vaccine delivered by spherical “nanoparticles” shaped like soccer balls. The synthetically produced RBD protein is immobilized on nanoparticles in a regular sequence. With this design, the vaccine can elicit an antibody response that is at least 10-fold higher than a vaccine that uses the entire natural peplomer, King said. “We’re not just adjusting existing proteins a bit, we’re creating brand new proteins to do exactly what we want,” he says. The vaccine is currently being tested in early stages or in Phase I trials by human volunteers. If successful, it may be open to the public later this year.

Other vaccines in the pipeline

These are just a few of the vaccine candidates under development. Other vaccines that may help delay pandemics, such as the vaccine developed by Sinovac Biotech in China, were used to help conquer polio and are still used in many influenza vaccines. It utilizes traditional designs such as technology). We still don’t know how well all of these approaches work. But with so much effort going on, there is good reason to expect the end of this pandemic nightmare to come to light.

And once that’s done, scientists have a lot of tools ready for the next pandemic.

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