Vaccination Against the Covid-19 Disease – Part 4

Author’s note:  This blog is part of a series on the current status of the Covid-19 vaccination program in the United States.  All information contained herein was obtained from peer reviewed scientific journals and publications as well as legitimate vetted science-based websites.  These sources are referenced such that you may obtain further information from them.  All information is based on scientific facts known at the time of publication.

Covid-19 Vaccine Comparison

The previous installments of this series have provided the basic, scientific facts regarding the history of vaccination, the biology behind the immune response as relates to vaccination and the methods utilized in preparing the current vaccines against Covid-19 disease. 

Currently there are three vaccines being used in the United States to vaccinate against Covid-19 disease being produced by Pfizer, Moderna and Johnson and Johnson.  A fourth vaccine produced by AstraZeneca has been submitted for FDA approval for Emergency Use Authorization (EAU) with a decision expected in April 2021.  Table 1 shows a comparison of the four vaccines.

The efficacy of a vaccine refers to the percentage of people who are protected from Covid-19 disease once they have been fully vaccinated.  All the vaccines are 79% or higher.  More importantly, all four of the vaccines provide protection such that even if the patient contracts Covid-19, the disease is not as severe and there have been no instances of any vaccinated patients becoming sick enough to go to the hospital and none have died. 

Table 1

Pfizer mRNA 95% 100% 2 Minus 94 C 43,000
Moderna mRNA 95% 100% 2 Minus 4 C 35,000
J and J Adenovirus 85% 100% 1 2 – 8 C 44,000
AstraZeneca Adenovirus 79% 100% 2 2 – 8 C 32,000

Like all viral diseases, including influenza, the SARS CoV-19 virus itself is mutating and changing as it moves through the human population on Earth.  Sometimes these variants arise and then naturally disappear.  Other times the variants may persist and even become the more dominant strain causing the disease.  Currently there are multiple variants of the SARS CoV-19 virus circulating around the globe, with the origin as follows:  United Kingdom B.1.1.7, South Africa B.1.351 and Brazil P.1.  These variants have been shown to spread more easily and quickly and efforts are being made to determine if they are more lethal.   On going studies indicate that the current vaccines against Covid-19 are effective against these variants (1).

The CDC Morbidity and Mortality report of December 23, 2020 stated 21 cases of anaphylaxis following COVID vaccination were reported out of about 1.9 million doses given.  That amounts to 11.1 cases per million versus an estimated 1.3 cases per million following inactivated influenza vaccine (2).  However, the vast majority of these instances occurred in patients that had previously existing allergies (3).  For that reason, patients who receive a Covid-19 vaccination are monitored for 30 minutes after receiving the injection.  Other minor side effects such as soreness at the injection site and headache, etc. after the second injection are common.

As of this writing (28 March 2021), in the United States 140 million doses of vaccine have been administered, with 50.1 million of those fully vaccinated, resulting in 15% of the American population being vaccinated (4,5).  Population immunity (i.e.  “herd immunity) is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection (6).  The percentage of the population that must be immune to the pathogen depends upon the disease.  For polio, the threshold is 80%, while the measles threshold is 95% (7).  Currently the threshold for Covid-19 disease is not known, however the target is 85% (8).  

For herd immunity to work in the United States, and over the globe, 85% of the total population must be vaccinated, or have obtained immunity through having Covid-19 disease.  In the US, vaccines will be made available to everyone who wants it.  This series has provided the facts regarding vaccination: the vaccines are safe, with minor side effects and they work to provide immunity against the SARS CoV-2 virus.  

The reason the vaccines have become available so quickly after the appearance of the first cases of the Covid-19 disease is not because of “fast tracking” the testing of the vaccines.  Rather, the novel biotechnology methods of using mRNA and adenovirus delivery systems are safe and quickly performed, using genetic detection techniques.

The way out of the Covid-19 pandemic is to have everyone get vaccinated.  Regarding which is the best vaccine to get, Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases since 1984, and co-author/editor of over 1,300 scientific publications, said it best:

“The best vaccine is the one that’s offered the day you go in for your appointment.”

When you get vaccinated, you are protecting not only yourself, but also your family, friends, coworkers and the rest of humankind.



Questions and comments may be sent to the author directly.
Clifford M Chapman
Senior Consultant
Medi-Sci Consultants

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