Understanding the Covid-19 vaccine 

Dr. Anthony Fauci, NIAID Director, gives the thumbs up sign after receiving the Moderna COVID-19 vaccine at the HHS/NIH COVID-19 Vaccine Kick-off event Dec. 22, 2020.
courtesy NIH | NIAID

Dr. Mark Saddler

Guest Author, Durango Nephrology Associates

The Covid-19 pandemic has been a catastrophic event which has affected all aspects of our lives. There have been 1.9 million deaths from this infection worldwide, with 373,000 deaths in the United States. At this time, the pandemic is not under control and there are currently about 4,000 deaths per day in the U.S. due to Covid-19; to put this in perspective, the 2001 9/11 attack resulted in a total of 2,977 deaths. In La Plata county to date there have been a total of 2,445 cases resulting in 30 deaths. 

Covid-19 disease is caused by a Corona virus; its scientific name is SARS CoV 2. Some people who become infected with this virus develop few or no symptoms. These asymptomatic carriers are an important source of ongoing infection, many of whom don’t know they are infected while they transmit the disease to others. People at highest risk of developing severe illness from Covid-19 infection include the elderly, and patients with underlying health conditions such as hypertension, heart disease, diabetes, kidney disease and immunosuppression.

One critically important way to control this disease is through vaccination. 

Historically, vaccines are known to be extremely effective and safe. Historically, effective vaccination programs have enabled eradication of some infections (for example smallpox) and control of others such as measles, mumps, influenza, tetanus, diphtheria, meningitis, and many others. It’s easy for us to forget that these illnesses were at one time frequent killers of young and old people; now we often take for granted that they rarely pose a threat, thanks to effective vaccines.

The development of a vaccine against Covid-19 has been a triumph of medical research. The first Covid-19 vaccines are now available, only about a year since the identification of the new Coronavirus. There has never before been such a rapid development of any vaccine; however, the development of these vaccines has still been subject to the usual FDA requirements to ensure their safety.

At the time of writing, there are two Covid-19 vaccines available. These are generally known as the Pfizer vaccine and the Moderna vaccine. These two mRNA (“messenger ribonucleic acid”) vaccines are similar to each other in many ways. They both use a novel but well-established vaccine delivery system which allows a person’s own cells to manufacture viral “spike” protein. This spike protein is not by itself harmful to the body. It stimulates the person’s immune system to produce antibodies: proteins which protect against future infection by real Coronavirus. The mRNA and spike protein are quickly eliminated by the body and there is no lasting effect other than the antibody production which is persistent and provides long lasting protection. We don’t yet know for sure how long this protection will last. These vaccines both require two doses separated by 3 to 4 weeks. It is important to get both doses of this vaccine for full protection.

How do we know these vaccines are safe? 

There are three phases of testing prior to these vaccines being approved by the FDA. In the final phase for the Pfizer vaccine, 18,566 volunteers received the Pfizer vaccination in a clinical trial (about the same number received a placebo shot of saline which did not contain any vaccine). Some of these volunteers noted soreness at the injection site, generalized muscle pain and headaches, but these effects were not severe. These types of side effects are similar to what is seen with other vaccinations and occur at similar rates. There have also been very rare instances of allergic reactions to the shot; these have been effectively treated at the vaccine administration sites without difficulty. A similar rate of side-effects was seen with initial trials of the Moderna vaccine, which included roughly the same number of volunteers.

At the time of writing, I personally have just received my second dose of Pfizer vaccine, and I have some minor muscle aches, but these symptoms are not severe, and I am very happy to have received protection against future infection with Covid-19! 

How effective are these vaccines? 

The Pfizer and Moderna vaccine both showed about 95% effectiveness in their clinical trials. This means that, compared with the placebo shot described above, the volunteers who received the vaccination were protected from 95% of infections. And the very small number of infections which did occur in the vaccine recipients were not severe infections. So, we can be confident that these shots provide effective protection from Covid-19 infection.

The goal of any vaccination program is to protect both individuals who receive the vaccination and the community at risk. Community protection is achieved by reaching a state where enough people are vaccinated that there is limited or no further transmission of the virus, a state known as “herd immunity.”

Despite the efficacy of the vaccination, it is still strongly advised to wear a mask, wash hands frequently, and practice social distancing, even after receiving the vaccine. 

There are recent new variants of the Covid-19 infection: small mutations in the virus which change its protein structure slightly. These variants appear to make the virus more transmissible: easier for it to spread from person to person. Initial data suggests that this mutation has not changed the virus’ susceptibility to the vaccine. So now it is even more important to be vaccinated before further spread of this highly contagious virus occurs.

If you have had minor reactions to another vaccine in the past (including fever, muscle aches, headache), it is still safe to receive Covid-19 vaccination. Only in very rare instances of severe allergy to specific types of vaccines should Covid-19 vaccination be avoided. It can be used in pregnant and breast-feeding women, though this should be discussed with your provider. Patients on immunosuppressive medicines (for example transplant patients) may also receive the vaccine. In fact, vaccination is strongly recommended in this group of patients because of their risk of severe complications of Covid-19 infection.

Future vaccines being developed

It is likely that different types of Covid-19 vaccinations will become available in the near future. Several are in the final stages of development and testing. These will be different from the current mRNA-type of vaccinations described above which are now available, and some will contain a non-harmful type of live virus. These newer vaccines may have different side effects, efficacy, and may not be suitable for certain groups of patients. Specifically, it may not be safe to give these newer vaccines which contain a type of live virus to immunosuppressed patients. We will learn more about these vaccinations in the next few weeks to months.

So, I strongly encourage everyone to get the Covid-19 vaccination! It is safe and effective, and is our best chance to protect ourselves, our families and our community from the terrible effects of Covid-19. Hopefully with this vaccine we can eventually move back towards a more normal existence. And in the meantime, please remember to wear your mask, socially distance and avoid large gatherings. 

My best wishes to everyone for a happier and healthier 2021

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