LETTER from RICHARD STERNBERG
Many people have asked me to explain vaccines to them, and specifically the ones for COVID-19. They are most concerned with how they work, when they will be available, and if they will be safe.
Hopefully, this column will help.
The terms vaccine and vaccination derive from the Latin name Variola vaccinae, which means small pox of the cow. Vacca is Latin for cow.
The term vaccine was first devised by Sir Edward Jenner in 1778 based on the fact that he used an inoculation with cowpox to elicit a protective reaction to smallpox.
In 1881, Louis Pasteur proposed that the term vaccine be used to cover all new protective inoculations that were developed in order to honor Jenner.
There are multiple types of vaccines and at least one of each type has been tried or is being developed for SARS-CoV-2 (the virus that causes COVID-19).
The following are the different types of vaccines that are administered to a subject to induce a protective immune response along with examples of each.
►INACTIVATED: a dead copy of the infectant, e.g., polio
►ATTENUATED: A weakened version of the infectant, e.g., yellow fever, measles, mumps
►TOXOID: an inactivated form of the poison made by the infected cell, e.g. tetanus and diphtheria
►SUBUNIT: a portion of the protein of the infectant that cannot cause the disease by itself, e.g., hepatitis B and HPV (human papillomavirus, causes genital warts and cervical cancer).
►CONJUGATE: Weak version of the infectant, coupled with a strong antigen for something benign to increase the immune response to the weakened version, e.g., Hemophylus influenza.
►RECOMBINANT DNA, where a stand of genetic material for part of the infectant is inoculated into the host’s cells and teaches the cells to make an antigen for part of the infectant.
►RNA: This is the approach that right now is the most promising in treating SARS-CoV-2. A portion of messenger RNA is inoculated into the host cells and tells the host to make a portion of the infecting virus. This technique has not been used for human diseases clinically before.
Typically, it takes 15-20 years to bring a new vaccine to market, and less than 5 percent of candidates will succeed. The speed in which the SARS-CoV-2 vaccine has come to be distributed really is warp speed.
The first regular immunizations begin a week ago Monday in Great Britain. This is less than a year from recognition that there was a new disease and 10 months from identifying the genetic code of the virus causing it.
Currently there is only one vaccine approved for use, the one made by Pfizer and BioNTech. This is awaiting approval along with that of Moderna in the United States. Pfizer’s was approved, distributed Sunday, and injection began Monday. Approval for Moderna may come later this week.
Both of these are of the RNA type.
There are several reasons that things have moved with lightning speed.
One, the unprecedented cooperation between pharmaceutical companies and academic and government research labs.
Two, the approval of governments to allow fast-tracking such that steps of the development are done in parallel. In my mind, there is no doubt the government’s Warp Speed initiative helped move the process along.
Three, scientists have been working for 10 years on what they call pandemic preparedness. In this case they had developed a template that would allow the development of vaccines for newly emerging diseases quickly. Essentially as one scientist called it, plug and play.
In my next column I will discuss plans for the roll out and how it has gone up to that point.
Normally, the time from submission of data to approval by a government agency takes two years. In the case of SARS-CoV-2 vaccines it is one week.
After approval, time to distribution takes more than a year while the pharmaceutical companies develop and implement manufacturing plans.
Amazing what we can do when everyone is desperately pulling in the same direction.