On Friday December 11, on the first day of Hannukah, the FDA gave Pfizer the Emergency Use Authorization to give us a truly remarkable gift – an mRNA vaccine against COVID-19. I read the peer-reviewed study of the vaccine that appeared in the New England Journal of Medicine. The results are truly miraculous: a 95% protection against COVID-19 infection, mild as well as severe, across different ages, ethnic groups, and comorbid illnesses.
The mRNA vaccine design led to its rapid development and outstanding efficacy. While Pfizer has created the first ever mRNA vaccine approved for human use, the concept has been refined for over 20 years. The lipid nanoparticle coating had already been developed. Once the Chinese published the RNA sequence of the virus in January 2020, the “blue-print” for the spike protein could be rapidly copied and inserted into the nanoparticle. The vaccine was ready for human studies within a few months.
Also, the vaccine mimics the way real viruses stimulate our immune system to create a very powerful response. The vaccine contains mRNA coated by fat particles, which allows the mRNA to stay intact and be injected into the deltoid muscle of the arm. These particles are then scavenged by lymphocytes which absorb the nanoparticles into the cells. There, the mRNA directs the lymphocytes to manufacture the spike protein, which becomes expressed on the outside of the lymphocyte cells. Which stimulates a cascade of responses to identify, destroy and remember the spike protein laden cells. The mRNA does not become a permanent part of our bodies; and the infected cells are destroyed within days. Potential side effects stem from our activated immune systems, not from a permanent foreign substance in our bodies.
The San Francisco Chronicle has published a helpful series of illustrations for this process:
Regarding safety, over 20,000 study participants received the vaccine and were observed for over two months. There were the usual side effects such as sore arm, fever, malaise and headache that are to be expected from vaccines that elicit a strong immune response. In the study, there were no serious side effects attributed to the vaccine. (Recent press reports from England of two treated anaphylaxis responses are from non-study patients receiving the vaccine.)
You may have read in the news about four cases of Bell’s Palsy among vaccine recipients in the Pfizer study and three cases among the vaccine recipients in the Moderna study, with one in the placebo group of that study. Bell’s Palsy is a transient paralysis of a facial nerve that coordinates muscles on one side of the face and is caused by an immune reaction of the body against its own nerve. The rate of Bell’s Palsy cases among the vaccine recipients in the two studies slightly exceeds the expected rate of the disease in the population. This could be due to statistical chance or possibly the immune stimulation due to the vaccine. However, no other vaccine used in the United States has been shown to cause Bell’s Palsy.
The example of Bell’s Palsy illustrates the problem of ascribing causality. With millions receiving the vaccine, undoubtedly many bad outcomes will occur in vaccinated individuals due to the underlying rate of other illnesses. I fear that the anti-vaccination movement will seize on visibly tragic cases as “proof of harm” from the vaccine and dissuade people from receiving this life-saving technology.
Is the vaccine safe? Vaccine safety needs to be evaluated relative to not receiving the vaccine. The original Pfizer study was a randomized, placebo-controlled double-blind trial designed to go on for two years. It was stopped early because the treatment benefit was so great: only 8 cases of COVID-19 infection in the treatment group versus 162 cases in the placebo group. Having met the pre-specified statistical criteria of efficacy, it was no longer ethical to withhold the vaccine from the placebo test subjects (and the rest of the world). However, when considering the safety of the vaccine, you can imagine comparing the total health outcomes across the two groups for two years. Any vaccine side-effects in the treatment group would have to be very severe to be more dangerous than the result of a twenty-fold greater rate of COVID-19 cases in the placebo group.
Next week the FDA is expected to approve a second mRNA vaccine manufactured by Moderna. Even with two approved vaccines there will still be a several month delay until we can get everyone vaccinated. We know that everyone is very eager to receive information about when they can receive a vaccine. Unfortunately, the exact production quantities, priority lists, and distribution plans are still being developed. Hence, no answers yet.
Our current policy:
- We will try to get vaccine supplies
- If we cannot get the vaccine, we will direct you to where you can
- There are no sign-up lists
- We will keep everyone updated by email blogs
I have enclosed an informative question and answer article on the vaccination process from the New York Times:
Please contact me with any concerns or questions.