An anonymous reader shares an excerpt from Wired: On Monday morning, when representatives from the drug company Pfizer said that its Covid-19 vaccine appears to be more than 90 percent effective, stocks soared, White House officials rushed to (falsely) claim credit, and sighs of relief went up all around the internet. […] The arrival of an effective vaccine to fight SARS-CoV-2 less than a year after the novel coronavirus emerged would smash every record ever set by vaccine makers. “Historic isn’t even the right word,” says Larry Corey of the Vaccine and Infectious Disease Division at the Fred Hutchinson Cancer Center. A renowned virologist, Corey has spent the last three decades leading the search for a vaccine against the virus that causes AIDS. He’s never seen an inoculation developed for a new bug in under five years, let alone one. “It’s never happened before, never, not even close,” he says. “It’s just an amazing accomplishment of science.”
And perhaps even more monumental is the kind of vaccine that Pfizer and BioNTech are bringing across the finish line. The active ingredient inside their shot is mRNA — mobile strings of genetic code that contain the blueprints for proteins. Cells use mRNA to get those specs out of hard DNA storage and into their protein-making factories. The mRNA inside Pfizer and BioNTech’s vaccine directs any cells it reaches to run a coronavirus spike-building program. The viral proteins these cells produce can’t infect any other cells, but they are foreign enough to trip the body’s defense systems. They also look enough like the real virus to train the immune system to recognize SARS-CoV-2, should its owner encounter the infectious virus in the future. Up until now, this technology has never been approved for use in people. A successful mRNA vaccine won’t just be a triumph over the new coronavirus, it’ll be a huge leap forward for the science of vaccine making.
[I]n the last decade, the field has started to move away from this see-what-sticks approach toward something pharma folks call “rational drug design.” It involves understanding the structure and function of the target — like say, the spiky protein SARS-CoV-2 uses to get into human cells — and building molecules that can either bind to that target directly, or produce other molecules that can. Genetic vaccines represent an important step in this scientific evolution. Engineers can now design strands of mRNA on computers, guided by algorithms that predict which combination of genetic letters will yield a viral protein with just the right shape to prod the human body into producing protective antibodies. In the last few years, it’s gotten much easier and cheaper to make mRNA and DNA at scale, which means that as soon as scientists have access to a new pathogen’s genome, they can start whipping up hundreds or thousands of mRNA snippets to test — each one a potential vaccine. The Chinese government released the genetic sequence of SARS-CoV-2 in mid-January. By the end of February, BioNTech had identified 20 vaccine candidates, of which four were then selected for human trials in Germany. […] Genetic vaccines might be proving they can work — but it’s still not definitive, and they may not yet work for everyone. That’s why experts say it’s so crucial to continue supporting ongoing trials for the more than 60 other vaccine candidates still in various stages of human testing. What older technologies lack in terms of speed, they make up for in durability.