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COVID-19 clinical trials and the promise of a vaccine

The Body Scientific
In the Northeast, there are few sites because there is a relatively low level of disease. If we want to test a vaccine, we have to go where disease rates are high—in the United States that means Texas, Alabama, Georgia, Arizona, Missouri and California.

The genome sequence of the SARS-Cov-2 virus was deposited on a National Institutes of Health (NIH) server on Jan. 10, 2020. Within days, scientists all over the world started to use the sequence to make vaccines. Two vaccines are now approved for limited use; eight vaccines are in large-scale phase 3 clinical trials; 13 are in expanded phase 2 safety trials; 21 are moving through phase 1 safety testing. 

More than 135 vaccines are at earlier stages of development. These numbers are being curated by the New York Times and are updated frequently. Search for their Coronavirus Vaccine Tracker; The Times will not fail to keep you updated. 

How the vaccines work

All of the vaccines are designed to present a SARS-CoV-2 spike protein to the human immune system and provoke the production of circulating antibodies and T-cells that kill lung or other cells infected with the virus. After a vaccination or illness, the immune response subsides, but many antibody-producing B cells and cell-killing T cells are banked. When infection occurs, thousands or millions of lymphocytes leap into action and block or minimize the infection. 

With some vaccines the banked cells last a long time; with others, only a few months

The spike protein is a string of about 400 amino acids in a unique order. During its synthesis, the protein folds into a spike shape and is assembled into the SARS-CoV-2. The tip of the spike protein grasps a protruding protein on the surface of human cells and the attached virus is pulled inside, where it unfolds and starts the production of much more virus. 

mRNA as one option

The vaccines in phase 3 testing are all products of genetic manipulation. In one approach, scientists inserted the gene that carries the information for the spike protein into an attenuated animal virus. The Oxford-AstraZeneca group uses a weakened chimpanzee adenovirus with an inserted spike protein gene. They have a Phase III trial in Arizona and lots of other places. The Chinese have four vaccines completing phase 3 and starting general use. 

The method that is most intriguing to me is purely chemical. Recipients get no live or dead virus, which is reassuring for some people. The new method makes the mRNA that provides instructions for the synthesis of the spike protein, but all in a test tube. The scientists wrap the coding mRNA in lipid and inject it into macaques or humans, where it enters cells and uses their protein synthesis capacity to make spike protein. 

In macaques, the mRNA-1273 vaccine successfully defends the host from the coronavirus. This novel vaccine is the product of Tony Fauci’s National Institute of Allergy and Infectious Diseases and a company called Moderna that specializes in RNA-based defenses against infectious disease. The vaccine is in phase 3 trials on 30,000 people. 

Seeking trial volunteers 

The study is recruiting volunteers. 

All clinical trials must register with an organization at the National Library of Medicine at the NIH. Anyone can find the list of clinical trials for a disease or condition at www.ClinicalTrials.gov. If you are interested in joining a SARS-Cov-2 clinical trial, you will also find medical centers involved in the trials at that website  (enter code identifier NCT04470427).

Being a participant requires commitment, because the people running a trial want to know if you produce antibody and new T-cells in response to a vaccination and how long it lasts — which means occasional blood tests. 

They want to know about side effects of inoculation. They are eager to have and are required to have participants of all ages and ethnicities. 

In the Northeast, there are few sites because there is a relatively low level of disease. If we want to test a vaccine, we have to go where disease rates are high—in the United States that means Texas, Alabama, Georgia, Arizona, Missouri and California.

The new techniques now being tested are effective and fast but we have to know about new viruses that will surely appear. New techniques will not do us much good if we ignore pandemic preparedness plans, eliminate virus surveillance programs, leave the World Health Organization, disparage the CDC and denigrate scientists and physicians who are trying to keep us alive. 

 

Richard Kessin Ph.D is Professor Emeritus of Pathology and Cell Biology at Columbia University’s Irving Medical Center. He can be reached at Richard.kessin@gmail.com.

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