More than 32 million doses of coronavirus vaccine have been administered in the United States, according to Feb. 3 data from the Centers for Disease Control and Prevention.
Many more are on the way. Pharmaceutical manufacturers are churning out hundreds of millions of doses. And just last month, Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said that the Food and Drug Administration could soon approve two more vaccine candidates.
This massive vaccination campaign is happening less than a year after health officials confirmed the first known case of the virus on U.S. soil. Now, we’re moving toward overcoming the pandemic. For that, we can thank animal research.
Consider how these vaccines came to be. The two vaccines currently authorized for use in the United States — developed by Moderna and a partnership between Pfizer and German firm BioNTech — were first determined effective in rhesus macaques. Humans share 93% of their DNA with these monkeys.
The next round of vaccines also has its roots in research in monkeys. Maryland-based Novavax, whose shot is in phase 3 clinical trials in humans, reported in July that the mice and non-human primates that received its vaccine developed an immune response after the first dose.
British drug firm AstraZeneca’s vaccine, which just received authorization in the United Kingdom, first proved itself in preclinical trials in monkeys at the University of Oxford. The vaccine candidate Johnson & Johnson developed — which, in contrast to the others, only requires one dose — is the product of research in rhesus macaques, too.
These latter two vaccines inject recipients with an adenovirus containing DNA with instructions for building the spike protein that rings the coronavirus. A person’s cells then start building that spike protein, which primes the immune system to produce antibodies that can neutralize the coronavirus and mark it for destruction.
Researchers have been investigating adenovirus vaccines in nonhuman primates for years in hopes of developing an easily modifiable template for fighting just about any pathogen. European regulators approved Johnson & Johnson’s adenovirus vaccine against Ebola in July. Work on adenovirus vaccines that would inoculate against HIV, influenza, and several other viruses is underway.
The vaccines developed by Moderna and the Pfizer-BioNTech team utilize a different approach. They build on the work of two University of Pennsylvania scientists who discovered over two decades ago that messenger RNA-based vaccines could initiate the creation of disease-fighting proteins in mice.
These mRNA vaccines introduce a sequence of mRNA that codes for a disease-specific antigen into the body’s cells. Once the body produces this foreign antigen, the immune system recognizes it and produces antibodies against it.
This technology has implications for many diseases beyond COVID-19. Scientists are developing mRNA-based Zika and flu vaccines.
BioNTech is also working on an mRNA vaccine against multiple sclerosis, which afflicts 2.3 million people worldwide. Existing treatments for MS suppress the immune system and consequently leave patients vulnerable to infection. The new mRNA technology targets specific MS-related proteins without compromising normal immune function.
The early returns are promising. The vaccine successfully alleviated symptoms in sick mice and prevented progression in those showing early signs of the disease.
Some critics of animal research have wondered how scientists could have developed the COVID-19 vaccine in less than a year when previous vaccines took decades to bring to market. Was it possible to skip some of the stages that have historically required animals in order to speed things up?
Hardly. Scientists conducted the basic research that’s at the foundation of every COVID-19 vaccine in animals.
After the pandemic hit, researchers first tested vaccine candidates for safety and some indication of efficacy in animal models. Then, with the permission of regulators, they tested the candidates for efficacy simultaneously in humans and animals.
It’s remarkable that scientists have been able to develop effective vaccines for COVID-19 within months. Animal research was instrumental in that effort — and will be behind the next miracle medical science brings about.
Matthew R. Bailey is president of the Foundation for Biomedical Research, a Washington, D.C.-based nonprofit that promotes ethical animal research.
