COVID-19 Vaccine FAQs

Dr. Kimberly Taylor, PNWU’s chief of microbiology, teams up with PNWU Student Doctor Claire Bernert to tackle some common questions related to the COVID-19 vaccine.

Should someone who has had COVID-19 be vaccinated?

The CDC recommends that all people over 12 years of age be vaccinated. In a recent study, the CDC identified that unvaccinated individuals were 2.34x as likely to be reinfected with COVID-19 compared to vaccinated people.

Studies show that people who have already been infected by SARS-CoV-2 can benefit significantly from vaccination, demonstrating a vaccine-induced immunity boost. When immunity that is generated from infection is combined with vaccine-generated immunity, a larger-than-expected immune response arises.

Upon receiving the first dose of a COVID mRNA vaccine, individuals previously infected with COVID-19 have displayed immunity levels comparable to an uninfected person who has received both doses. In fact, in those previously infected, a single vaccine dose can boost the antibody response by up to 1,000-fold. This response is significantly higher than that of non-infected people who received two doses of an mRNA vaccine.

What is the difference between the three vaccines in the U.S.?

Pfizer-BioNTech™ (“Pfizer”™) and Moderna™ are mRNA based vaccines whereas the Janssen/Johnson & Johnson™ (“J&J”™) uses a vector-based vaccine.

Pfizer™ and Moderna™ use mRNA to code for a spike protein found on the outer membrane of the SARS-CoV-2 virus. J&J™, on the other hand, uses a vector-based method which inserts a harmless adenovirus that contains the code for the spike protein. The small spike protein is produced without SARS-CoV-2 being present, which allows the body’s immune system to build antibodies to the spike protein.

Why do Moderna™ and Pfizer™ have two doses, but J&J™ only has one?

Moderna™ and Pfizer™ entered Phase 3 of vaccine trials as two doses since the previous trials did not show a robust immune response to only one dose. J&J™, however, proceeded to Phase 3 as one dose due to a strong level of immune response.

Why are there breakthrough infections?

A breakthrough infection is defined as a fully vaccinated (two or more weeks after the last dose of a COVID-19 vaccine) person who tests positive for COVID-19. From Phase 3 vaccine trials, Pfizer™ is 95% effective, Moderna™ is 94.1% effective, and Johnson&Johnson is 66.3% effective.

While there are rare breakthrough infections, the CDC has reported that unvaccinated people are 4.5 times more likely to contract COVID-19, 10 times more likely to be hospitalized for COVID-19, and 11 times more likely to die from COVID-19. While breakthrough infections in those vaccinated can and do occur since no vaccine is 100% effective, they are proving to be rare and are typically mild.

If the vaccines work, why must vaccinated people keep wearing masks?

While vaccines are safe and highly effective at preventing serious illness and death from COVID-19, breakthrough infections are possible. The CDC has recommended that fully vaccinated people wear masks in public indoor spaces in communities where transmission of COVID-19 is substantial to high. Yakima is currently classified as experiencing high transmission of COVID-19.

Vaccinated people infected with COVID-19 may be able to spread COVID-19 via respiratory droplets. With vaccination levels hovering around 50%, wearing a mask, regardless of vaccination status, is critical to keeping our communities healthy.

How new is the vaccine technology being used?

mRNA research dates back to the 1960s, with vaccine research first starting in the 1990s with influenza in mice.

How were these vaccines produced and distributed so fast?

The mRNA technology used to develop COVID-19 vaccines has had hundreds of scientists working diligently to create safe and effective vaccines. The technology underpinning the COVID vaccines has been in development for the past two to three decades. When SARS of 2002-03 emerged, vaccine development in the coronavirus area developed even further, but preclinical studies were not brought to clinical trial based on the quickly diminished community transmission of that particular coronavirus. Studies have continued since then and the scientific and medical community continued to advance knowledge in this area in preparation for the need we now see with SARS CoV-2 transmission.

What is mRNA?

mRNA (“messenger Ribonucleic Acid) is a nucleic acid that is made naturally in our cells and plays a central role in turning genetic information into proteins.

Can mRNA integrate into host cell DNA?

No, mRNA cannot integrate into DNA. mRNA is located in the cytoplasm of the cell while DNA is in the nucleus. mRNA given in a vaccine is like the mRNA made naturally in our cells and interacts with the ribosomes located in the cytoplasm.

What happens to the mRNA once it is in the body?

mRNA is translated (tells the cell how to make a protein) and then is degraded by the cell. mRNA degrades quickly and must be held at specific temperatures, which is why Moderna™ and Pfizer™ vaccines must be kept at -80°C.

Are vaccines recommended for pregnant people?

Yes, the CDC has recommended COVID-19 vaccination for anyone who may be pregnant. 2,456 pregnant folks were followed post-vaccination and there was no indication of an increased risk of miscarriage or risk to the fetus. Pregnant and recently pregnant people have an increased risk of becoming seriously ill, death, and having a preterm birth due to the complications of COVID-19. Not only can the COVID-19 vaccine protect pregnant people, but it can also help protect their babies.

Are vaccines recommended for nursing people?

The CDC has recommended that all people over 12 years of age be vaccinated against COVID-19 regardless if they are pregnant, planning to become pregnant, or breastfeeding. An early research study indicates that antibodies produced by the pregnant individual from the COVID-19 vaccine may be passed down through the breastmilk and placenta to help protect the fetus.

Can the COVID-19 vaccines cause myocarditis? How common is it?

Myocarditis is inflammation of the heart’s muscle fibers. mRNA COVID-19 vaccines may cause myocarditis in rare cases, with the highest prevalence in assigned males at birth ages 12-17 reporting 62.8 cases per one million vaccines. These reports are rare and COVID-19 vaccines are safe and effective.

Written by: Claire Bernert, PNWU-COM Class of ’24, and Kimberly Taylor, Ph.D.