“A lot went into the mRNA platform that we have today,” says immunologist Akiko Iwasaki at the Yale School of Medicine in New Haven, Connecticut, who has worked on nucleic-acid vaccines - those based on lengths of DNA or RNA - for more than two decades. The vaccines made by Pfizer and BioNTech and by the US pharmaceutical company Moderna both use mRNA that encodes the spike protein, which docks to human cell membranes and allows the coronavirus to invade the cell. That acts as the antigen - the foreign molecule that triggers an immune response. The mRNA encodes a key protein of SARS-CoV-2 once the mRNA gets inside our cells, our bodies produce this protein. But the first two COVID-19 vaccines for which efficacy was announced in large-scale (phase III) clinical trials used just a string of mRNA inside a lipid coat. Credit: Kevin Frayer/GettyĬonventional vaccines contain viral proteins or disabled forms of the virus itself, which stimulate the body’s immune defences against infection by a live virus. Vials of Sinovac Biotech’s COVID-19 vaccine on a production line in Beijing. For years, researchers had been paying attention to related coronaviruses, which cause SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), and some had been working on new kinds of vaccine - an effort that has now paid off spectacularly. The research that helped to develop vaccines against the new coronavirus didn’t start in January. With SARS-CoV-2, a virus that mutates relatively slowly and that happens to belong to a well-studied family, scientists might - strange as it sounds - have got lucky. It will depend, too, on the nature of the pathogen. To repeat such rapid success will require similar massive funding for development, which is likely to come only if there is a comparable sense of social and political urgency. Some of those factors might translate to other vaccine efforts, particularly speedier manufacturing platforms.īut there’s no guarantee. The world was able to develop COVID-19 vaccines so quickly because of years of previous research on related viruses and faster ways to manufacture vaccines, enormous funding that allowed firms to run multiple trials in parallel, and regulators moving more quickly than normal. The first UK injections of a fully tested COVID-19 vaccine were given in early December. “It has shown that the development process can be accelerated substantially without compromising on safety.”
New ways of making vaccines, such as by using messenger RNA (mRNA), have been validated by the COVID-19 response, he adds. “It shows how fast vaccine development can proceed when there is a true global emergency and sufficient resources,” he says. The COVID-19 experience will almost certainly change the future of vaccine science, says Dan Barouch, director of the Center for Virology and Vaccine Research at Harvard Medical School in Boston, Massachusetts. These are sorely needed: diseases such as malaria, tuberculosis and pneumonia together kill millions of people a year, and researchers anticipate further lethal pandemics, too. It’s tempting to hope that other vaccines might now be made on a comparable timescale. That speed of advance “challenges our whole paradigm of what is possible in vaccine development”, says Natalie Dean, a biostatistician at the University of Florida in Gainesville. And on 2 December, a vaccine made by drug giant Pfizer with German biotech firm BioNTech, became the first fully-tested immunization to be approved for emergency use.
To hope for one even by the summer of 2021 seemed highly optimistic.īut by the start of December, the developers of several vaccines had announced excellent results in large trials, with more showing promise. The fastest any vaccine had previously been developed, from viral sampling to approval, was four years, for mumps in the 1960s. When scientists began seeking a vaccine for the SARS-CoV-2 coronavirus in early 2020, they were careful not to promise quick success.
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