COVID-19 Vaccine Questions and Answers with Dr. Bunce
Dr. Christopher Bunce, Schneck Infectious Disease - January 06, 2021

Pfizer and Moderna COVID VACCINES: Some Questions and The Facts


How does the COVID vaccine work?

The SARS-CoV2 vaccine contains a small piece mRNA tucked inside of a lipid nanoparticle. This molecule (mRNA) is not taken from the virus itself but is manufactured using the known genomic sequence of the SARS-CoV2 virus. This molecule is carried by the lipid nanoparticle into your arm by the vaccine injection. Your own cells ingest the particle and the mRNA starts to produce a viral protein called the spike protein. This protein will be identified by your immune system as an invader and you will have a normal immunological reaction to it, ultimately providing protection.


How is the COVID vaccine different from other vaccines?

The vaccine is different from other vaccines in two basic ways:

  1. It does not require growing the virus to make the 2 vaccine components, just a set of instructions to manufacture the mRNA molecule.
  2. It uses mRNA which lets your own cells make the viral protein, the first approved vaccine using this method. Like some other vaccines, two shots are recommended to get the best level of protection. Both the Pfizer and Moderna vaccines utilize the same technology and are consider equal in safety and efficacy. The Pfizer injections are 21 days apart and the Moderna injections are 28 days apart. There is no reason at this point to prefer one over the other.

How was it approved so quickly?

The vaccine may seem rushed, but in reality it was a massive prioritization effort requiring coordination between agencies within department of Health and Human services and the pharmaceutical industry. All the usual steps were taken including phase 1, 2, and 3 randomized, blinded, placebo controlled trials which demonstrated both safety and efficacy. After careful review by a panel of vaccine experts, both vaccines were approved under an emergency use authorization (EUA).


What are the ingredients? Any concern with those?

The ingredients are simple; a lipid nanoparticle (a small sphere made of fat molecules) and mRNA. A small number of additional ingredients are routine and not unusual for medications designed for injection into a muscle. The unique ingredient is the lipid particle with the mRNA inside. In addition to about 70,000 people who participated in the clinical trials, about 5 million Americans have received the vaccines as of January 5, 2021.


What are the potential side effects?

Side effects to both the Pfizer and Moderna vaccines are both common and mild: pain at the injection site is the most common side effect reported. Others include muscles aches, headache, fatigue, and low grade fever. Common mild side effects may happen more often after the second dose. A few severe allergic reactions have been reported in persons with prior histories of severe allergic reactions (anaphylaxis). It should be emphasized that these kinds of reactions are very rare.


But what about rumors?

It is important to ignore rumors that have no basis in fact. Here are the facts:

  1. The vaccine cannot enter your DNA and cannot change your DNA in any way.
  2. The vaccine has no effect on male or female fertility.
  3. After the COVID vaccine does its work, the body quickly breaks it down. It doesn’t linger or cause problems. 
  4. Vaccines (including COVID vaccine) do not make your immune system weaker. On the contrary, all vaccines strengthen your immune system by giving it a stimulus which causes a normal and natural immune response, preparing you in advance for facing potentially deadly infections. It’s a bit like giving your body a look at the viral playbook ahead of the game, increasing the chances of victory (but it’s not cheating!).
  5. Much like your brain, your immune system has memory. It remembers the things it has encountered, both vaccinations and natural infections. The more experience your immune system has, the stronger it becomes.

For someone who is reluctant to take it, what would you like them to know?

If you are reluctant to take the vaccine, be honest with yourself and ask yourself why. Often these doubts are based on misinformation circulated on social media and by other dubious sources. Seek out official reliable mainstream sources, your health department, and above all discuss your concerns with your doctor.

In addition, think beyond yourself and realize that you are part of a family, a workplace, and a community. Taking the vaccine protects those around you as well as yourself. Think about how you are protecting the most vulnerable members of your family, your church, and community.

VACCINE UPDATE:  Hoosiers age 80 or older can register to recieve the vaccine starting Friday, January 8, 2021.  Additional groups, such as those with underlying health conditions will be added as more vaccines become available.  To register and check availability, visit