A dead or weakened virus enters a healthy person, generating antibodies and stimulating the immune system; once the process is finished, the vaccinated person is completely protected once the true pathogen attacks her organism.
Over the decades, this approach beat polio, eradicated smallpox, and controlled chickenpox, measles, and mumps, but vaccine production has never been as simple or fast as it sounds at first glance. Many flu vaccines are still grown in chicken eggs, and new approaches are based on genetic engineering still do not prevent the development of viral proteins.
By cons, Coronavirus vaccines from Moderna Inc., in Cambridge, Massachusetts, and its German rival BioNTech SE propose to immunize people in a radically different way: harnessing human cells to turn the body into a “vaccine factory” on its own. Instead of viral proteins, vaccines contain genetic instructions carried by messenger RNA (mRNA) that prompt the body to produce them.
Moderna’s mRNA-1273 consists of a strand of mRNA that tells the body to produce the spike protein that the coronavirus uses to adhere to human cells. If the vaccine works as intended, the body start to make protein shortly after injection, prompting the immune system to react and accumulate protective antibodies against them.
In his favor, the great advantages of mRNA vaccines it’s speed and flexibility; Unlike their rivals, they don’t need tedious living cells or unwieldy viruses, and the basic chemistry is fairly easy to handle.
In this case, Moderna’s vaccine It reached Phase I human testing on March 16, just 63 days after the company began developing it.. Just 4 months later, on July 27, the first test injection occurred in a volunteer. Less than 12 hours later, BioNTech and its partner, Pfizer Inc., announced their final stage of testing. All a record time accompanied by good results.
Thus, phase I trials by Moderna and BioNTech-Pfizer have focused on stimulate the immune system, produce antibodies and neutralize the virus with the body’s own resources. In this way, they would be the cells that would produce their own vaccines, an objective that for the moment seems more than feasible.
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According to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, “Neutralizing antibodies are the gold standard of protection“.
Of course, not everything is rosy. Historically, mRNA vaccines have not enjoyed a good press – they have rarely made it to the final stage – and they are not free of side effects. Only in the case of Moderna, its phase I produced up to 15 mild effects at medium dose and 3 severe temporary reactions at high dose. Although the evidence has improved since then, there are many skeptics of these types of vaccines.
“I can’t find any reason to focus on mRNA vaccines. I just do not get it”, shares Peter Jay Hotez, dean of the National School of Tropical Medicine at Houston Baylor College of Medicine, a Bloomberg. Even so, the professor does not lose hope with Moderna, which he sees as “promising” at times.
Ultimately, mRNA advocates hope it will become a springboard for vaccines for other difficult-to-treat infections, as well as personalized injections for cancer and even treatments for heart disease. “This is a great time for mRNA therapeutics in general, because now it’s a household word and everyone knows it.says Derrick Rossi, a stem cell biologist and co-founder of Moderna.
The vaccine already protects mice
The latest finds from Moderna show that the investigational vaccine induced neutralizing antibodies in mice when given as two small dose intramuscular injections (1 mg) 3 weeks apart. Although there is still much to do, the results are optimistic and they present a bright horizon for mRNA defenders.
In additional experiments it was discovered that rodents, who faced the virus after receiving the vaccine, were protected from viral replication for the entire duration of the experiment, with a maximum of 13 weeks. The authors note that these studies, combined with primate research and phase 1 clinical trials, support the evaluation of mRNA-1273 in clinical efficacy trials.
“This is a demonstration of how the power of new technology-driven concepts, such as synthetic vaccinology, facilitates a vaccine development program that can be started with only pathogen sequences“concludes the study, published in the magazine Nature.