By Steve Baragona
A vaccine against the new Wuhan coronavirus may start testing in as little as three months, according to National Institute of Allergy and Infectious Diseases Director Anthony Fauci.
It took 20 months before a vaccine against severe acute respiratory syndrome, SARS, was ready for clinical trials.
That doesn’t mean you can line up for a shot in three months. The vaccine will need to be tested for safety and efficacy. That will take months more.
But the time it takes to go from outbreak to vaccine candidate is shorter than ever, thanks in part to a new kind of vaccine.
Eighteenth century tech
Ever since Edward Jenner developed the first vaccine in the 18th century, against smallpox, vaccines have worked essentially the same way. Patients get an inoculation containing a weakened or killed germ or some of its key proteins. The body’s immune system reacts to it, and the next time the germ shows up, the body can recognize and neutralize it.
Companies grow the germs or germ parts in chicken eggs or vats of live cells. Manufacturing enough vaccine-ready germs or proteins for millions of shots takes a year or more in big manufacturing facilities.
In recent years, though, scientists have started exploring a different approach. Rather than injecting part of the germ itself, experimental vaccines deliver the genetic blueprints for germ parts and let the patient’s own body manufacture them.
The active ingredient in these vaccines is DNA or RNA, the genetic instructions for building proteins.
“You don’t even need an infectious virus,” said molecular microbiology professor Andrew Pekosz at Johns Hopkins Bloomberg School of Public Health. All scientists need is the virus’s genetic code. “And that became available very early in this outbreak,” he said.
Vaccine design in three hours
Chinese scientists first announced cases of unusual pneumonia Dec. 31, 2019. By Jan. 11, they had isolated the new coronavirus and published its complete genome.
With the virus’s blueprints in hand, Inovio Pharmaceuticals designed a vaccine in three hours. Manufacturing started the next day.
“It’s pretty remarkable, right?” said Kate Broderick, Inovio’s chief of research and development.
Inovio’s vaccine is based on DNA. Two other companies, Moderna and CureVac, are using what’s called messenger RNA. If DNA is the master blueprint for a protein, mRNA is the working copy taken to the construction site. It’s what the body’s machinery uses to turn blueprints into finished products.
Both methods are easily adapted when a new disease appears. Inovio has a vaccine in clinical trials against Middle East respiratory syndrome, caused by another coronavirus. The company also is working on vaccines for Zika, Ebola, Lassa, HIV and others.
DNA and RNA medicines also have the potential to treat cancer. Inovio, Moderna and CureVac are among the companies with genetic therapies in the works for cervical, lung, skin, prostate and other cancers.
The technology has been around for about 20 years, Broderick said, but has made big advances in recent years. There are no human DNA or RNA medicines on the market yet, but there are several for animals, including treatments for West Nile virus in horses, a viral disease in salmon, melanoma in dogs and a gene therapy that produces growth hormone in pigs.
Clinical trials and tribulations
While a DNA or RNA vaccine is quick to make, “what takes time — and it should take time — is the process of testing it,” Broderick said.
After manufacturing, animal safety tests will take a few months. Then the first phase of clinical trials can begin. Phase 1 tests for safety in healthy volunteers will take three months, according to NIAID’s Fauci.
After that, “some vaccines can get emergency approval for use in these epidemics,” Pekosz at Johns Hopkins said, “particularly if they’re the only means by which people can be afforded some level of protection.”
Once a vaccine is proved to be safe, researchers then must prove it works. That takes several months more.
By then, the outbreak could be over. That’s what happened with SARS. By the time researchers got an experimental vaccine through phase 1 safety trials, old-fashioned quarantine had stopped the virus from spreading.
“This is always the problem that we have with these outbreaks,” Pekosz said. Once the outbreak is over, “interest in generating the vaccine wanes, and the perceived need for the vaccine then wanes,” he added, “and these vaccines end up in this never-never land of being partially studied, but never pushed all the way through to completion.”
And then another outbreak hits.
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“We could have done a much better job of preparing for this epidemic if we just followed through on some of the SARS vaccine work all the way to its completion,” he said.
That’s a job government agencies should be doing, he said, “so that we do have data on how good a vaccine is before we actually need it.” (VOA)