The strong early results for two Covid vaccines have implications beyond the current pandemic—to treatments for cancer, heart disease, and other viruses.
The two leading vaccines, including one developed by BioNTech, are based on a new gene-based technology that could help fight a range of diseases.
To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. That immune response, which produces antibodies, protects us from getting infected if the real virus enters our bodies.
Never before have mRNA vaccines — such as the two-dose Pfizer/BioNTech and Moderna vaccines that have now received emergency use authorization from the FDA — been approved for use in any disease. How do they differ from traditional vaccines, and what makes them so exciting?
“It’s 21st-century science,” said William Schaffner, professor of preventive medicine at Vanderbilt University School of Medicine. The positive data for mRNA-based Covid-19 vaccines bodes well for the technology’s potential to combat future outbreaks of infectious diseases, he said.
“With traditional vaccines, you have to do a lot of development. You need a big factory to make the protein, or the virus, and it takes a long time to grow them,” says Robert Langer, the David H. Koch Institute Professor at MIT, a member of the Koch Institute, and one of the founders of Moderna. “The beauty of mRNA is that you don’t need that. If you inject nanoencapsulated mRNA into a person, it goes into the cells, and then the body is your factory. The body takes care of everything else from there.”
With mRNA, vaccine development becomes an engineering issue, rather than a scientific challenge. Companies can design mRNA vaccines relatively quickly once they know the genetic sequence of the pathogen. Researchers use the genetic sequence of a targeted virus to program the mRNA that can fight it.
In the journal Nature Reviews Immunology last November, the National Institute of Allergy and Infectious Diseases’ Anthony Fauci and John Mascola wrote, “MRNA has the potential to be a rapid and flexible vaccine platform. Starting from gene sequence, mRNA vaccines can be produced in a few weeks.”
Messenger RNA is one of a number of new technologies drug companies are using in what is emerging as a once-in-a-generation test of human ingenuity.
Already, mRNA vaccines are being tested for other infectious agents, such as Ebola, Zika virus, and influenza. Cancer cells make proteins that also can be targeted by mRNA vaccines: indeed, recent progress was reported with melanoma. And theoretically, mRNA technology could produce proteins missing in certain diseases, like cystic fibrosis.
One of the advantages of mRNA vaccines is that they can be quickly adjusted so vaccines can better respond to an eventual decline in immunity or virus mutations, which could render other vaccines less effective. Currently is under investigating ways to encode multiple viral proteins into a single vaccine, which could help produce a more potent immune response against a virus.
”A lot went into the mRNA platform that we have today,” says immunologist Akiko Iwasaki at the Yale School of Medicine, who has worked on nucleic-acid vaccines — those based on lengths of DNA or RNA — for more than two decades. The basic research on DNA vaccines began at least 25 years ago, and RNA vaccines have benefited from 10–15 years of strong research, she says, some aimed to developing cancer vaccines. The approach has matured just at the right time; five years ago, the RNA technology would not have been ready.
The COVID-19 experience might also prompt a regulatory rethink. Although there has been no relaxing of the stringent criteria for vaccine approval, the first candidates are mostly being approved under emergency-use regulations. These are faster but require companies to conduct follow-up surveys to look for side effects and continuing efficacy.
A review of the regulatory landscape established that, across 24 countries, there are at least 51 pathways to various types of accelerated vaccine approval.
Greater harmonization offers many benefits, but would also require companies to allow the creation of — or help to create — a secure means of sharing data for regulators, many of whom are not currently permitted to do this. If regulators all had access to the same data, it would be easier for them to compare their findings and analyses with those of others. Their decisions would be more robust and that, in turn, would shore up public confidence in immunization.
One year after the first known case of coronavirus infection, this pandemic, which has killed more than 1.7 million people, could, hopefully, be coming to an end at last.
Additional reading:
Why are mRNA vaccines so exciting? – Harvard Health Blog: http://ow.ly/wgvy30rpZ1J
The Promise of mRNA Vaccines – The Scientist Magazine: http://ow.ly/IHGR30rpZ1n
Explained: Why RNA vaccines for Covid-19 raced to the front of the pack -MIT News: http://ow.ly/QhRx30rpZ4d
Moderna and Pfizer Are Reinventing Vaccines, Starting With Covid – The Wall Street Journal: http://ow.ly/zPMl30rkCBp
The lightning-fast quest for COVID vaccines — and what it means for other diseases – Nature: http://ow.ly/Onsw30rq03Y
A review of 2020 through Nature’s editorials: http://ow.ly/txQe30rq047
