21+ mRNA Vaccine Questions Answered for Nurses
The mRNA vaccines for COVID are being distributed, and as a nurse it's important to know these vaccines, how they work, and their safety data.
Our patients respect our medical opinion, and we need to give accurate information so they can make an informed decision. This article focuses on the mRNA vaccines (Pfizer and Moderna), the vaccines currently distributed under FDA emergency use authorization.
Historical Context — Last Updated January 2021
This article reflects the data available in early 2021, when these vaccines first received emergency use authorization. It is preserved as written. The author is a nurse practitioner who saw COVID patients on the frontlines in the ED — not an epidemiologist — and bases these answers on the published data and firsthand clinical experience.
How mRNA Vaccines Work
1. How do mRNA vaccines work?
Vaccines generally work by introducing a dead or weakened virus, or part of a virus, into your body via an intramuscular or subcutaneous injection. This creates an immune response that helps your body attack the real virus on future contact. Typical vaccine types include:
Safety & Efficacy
2. Are mRNA vaccines safe?
This isn't an easy question since they're so new, but so far they seem very safe and effective. While mRNA vaccines hadn't been used widely in the US, researchers had been studying them for decades and tested them on humans for viruses like rabies, flu, CMV, and Zika. To test the new vaccines, clinical trials were conducted.
Over 30,000 people were enrolled in the Moderna trial and over 40,000 in the Pfizer trial. Pfizer involves 2 injections 21 days apart (tested in those 16+); Moderna involves 2 injections 28 days apart (tested in adults 18+). What they found: most symptomatic COVID cases occurred in the placebo groups, and severe cases almost exclusively occurred in the placebo group. Both vaccines use essentially the same mRNA and had very similar findings — reassuring and reproducible. Read more about the Pfizer and Moderna trials.
Side Effects & Reactions
3. What side effects can be expected?
Common side effects include local injection site pain, headache, and fatigue. These vaccines should not cause COVID symptoms such as cough or shortness of breath — it is impossible for them to cause actual COVID disease. These vague side effects are common and expected, and are often an indication of the body's immune response. They are short-lived (1–2 days). Symptoms after the first injection tend to be milder; symptoms after the second tend to be more significant but still brief.
4. Can the mRNA vaccines cause anaphylaxis?
Just like any medication or vaccine, allergic reactions can occur. Anaphylactic reactions have occurred after COVID vaccination, although not commonly, and seem to mainly occur in those with a history of severe allergies. It appears very rare — about 11 people per million. Regardless, we know how to treat anaphylaxis very well: Benadryl, Solu-Medrol, and Pepcid.
CDC Monitoring Windows
The CDC recommends those without a history of anaphylaxis wait 15 minutes after injection for monitoring, and those with a history of anaphylaxis wait 30 minutes.
Related: Adverse Drug Reactions Nurses Need to Know
5. Can the mRNA vaccines cause facial paralysis?
Bell's palsy is unilateral facial paralysis, usually temporary. In the trials there were 7 reported cases of Bell's palsy among the 70,000+ participants. While there were slightly more cases in the vaccine groups, this rate is consistent with Bell's palsy rates in the general public, so it's likely not statistically significant. Some viruses and vaccines have been associated with Bell's palsy in the past, though rarely. Even if there is a small chance, it is usually temporary and treatable, and the benefits outweigh the risks.
Related: The Cranial Nerve Assessment for Nurses
Common Myths
10. Do the mRNA vaccines cause infertility?
There is no convincing evidence that the mRNA vaccines cause infertility. This idea was picked up by anti-vax propaganda. The myth started when a German epidemiologist and a former Pfizer employee asked the FDA not to grant authorization, claiming the vaccine's mRNA is similar to the syncytin-1 protein used in mammals to help create placenta during pregnancy. While the proteins share a minimal amount of similar code, the scientific and medical community rejects the notion that it could cause infertility. It's still so new that it can't be said with certainty, but 23 women conceived during these trials and are still being followed.
Special Populations
11. Can pregnant patients get an mRNA vaccine?
This decision should be discussed with the patient's OBGYN. The trials did not study vaccination in pregnant mothers, so we don't have specific data, though some animal studies looked promising. The American College of Obstetricians and Gynecologists (ACOG) recommends that COVID-19 vaccines should not be withheld from pregnant individuals who meet vaccination criteria. What we do know is that pregnant mothers are at increased risk from COVID — more likely to be hospitalized, placed in the ICU, ventilated, and to die than if they weren't pregnant.
12. Can breastfeeding mothers get the vaccine?
Again, this should be decided with the patient's OBGYN and pediatrician. There is just not enough data to make a sweeping recommendation. It is unlikely the vaccines would be unsafe for the baby, and there is a possibility of passing on some passive immunity to a breastfeeding infant.
13. Can those with autoimmune diseases get the vaccine?
While there don't appear to be any specific contraindications, this should be discussed with the patient's physician / rheumatologist. The risks of getting symptomatic COVID may be worse than the risks of getting the vaccine.
14. Should patients who had symptomatic COVID get the vaccine?
The idea is that if you had symptomatic COVID, you should already have natural antibodies — so why get the vaccine? This is a decision to make with your provider. It likely won't hurt and could help, so the CDC favors vaccination even for those who had COVID. It may be recommended to wait 90 days after symptomatic COVID, but this isn't a firm rule — it's more about letting those without any immunity receive the vaccine first. Get vaccinated after you recover and when you feel it's appropriate.
Related: These 8 COVID Nursing Tips Could Save Your Life
After Vaccination
15. What if you or your patient doesn't get the vaccine?
COVID has killed over 400,000 people in the US and 2.15 million worldwide, and this number is rising quickly. Even if COVID doesn't kill you, it can cause many long-lasting side effects. During active infection it can cause multifocal pneumonia and respiratory failure; severe COVID can cause blood clots leading to pulmonary embolisms and embolic strokes, and inflammation of the brain and heart with irreversible damage in some cases.
Observational studies show up to one-third of patients with symptomatic COVID had persistent symptoms after resolution:
There may be other long-term side effects we still don't know about. So what's riskier — a vaccine that seems very safe, or taking your chances with COVID? That's a decision you and your patients have to make.
16. If you get the vaccine, what can you expect?
You can expect 2 injections, 21 days apart with Pfizer or 28 days apart with Moderna. Full efficacy seems to be established about 1–2 weeks after the second injection (1 week after Pfizer, 2 weeks after Moderna) — the timelines studied in the trials.
17. Can I stop wearing masks and social distancing once vaccinated?
Not immediately. A 94–95% efficacy still leaves 5–6% of people who can still get symptomatic COVID, who will likely be contagious and could get severe disease. Both vaccines require 2 shots before full efficacy, and the body takes 1–2 weeks after the second dose to build a response. Additionally, it has not been proven that these vaccines prevent you from spreading COVID — the trials only prove they reduce symptomatic COVID. Even without symptoms, you could possibly spread it.
18. Could you get the vaccine and be an asymptomatic spreader?
Theoretically, it's unlikely you'll spread the virus after vaccination, since your body should have created antibodies that attack COVID before it replicates. However, we don't have the data to back this up, and there's another consideration — mucosal immunity. We don't know how well the antibodies penetrate the nasal mucosa, so the virus might still replicate in the nasopharynx. While it may not cause symptomatic disease, you might still spread it when coughing, sneezing, or breathing. This is why it's imperative to continue to wash hands, wear masks, and practice social distancing.
The Big Picture
19. When will herd immunity be established?
It's going to take time for the majority of the US to become vaccinated. We need about 70%+ of the population to be vaccinated or infected before some type of herd immunity can be expected. Herd immunity occurs at different percentages for each virus; the exact number is unknown for COVID, but experts say at least 70% need to be vaccinated and/or infected. Mask mandates and social distancing likely won't be "a thing of the past" until we get there.
20. Will the mRNA vaccines cover the new strains?
Unfortunately, multiple mutated strains or variants are popping up. These strains are spreading fast as they're more contagious (30–70% more transmissible), though they don't necessarily seem more deadly. With surges in cases and hospitalizations, increased deaths could occur due to the burden on the healthcare system. As far as we know, these vaccines should be effective against the variants. However, preliminary data suggests they may not work as well against the South African variant — so Moderna has already begun production on a "booster shot" to specifically target these variants.
21. How long will immunity last from these mRNA vaccines?
Complete immunity is not guaranteed. If antibodies are created, it is unknown how long they will last. What we do know is that immunity wanes over time, and those who get symptomatic illness tend to build a better immune response than those who get vaccinations. Many patients who had symptomatic COVID in early 2020 still have antibodies — good news. We don't know how long immunity will last, nor how much further mutations will alter its effectiveness.
Other Vaccines
22. Are there other vaccines available?
Pfizer and Moderna are mRNA vaccines that have already obtained emergency use authorization. Two other vaccines may obtain approval as well — these are not mRNA vaccines:
These do not appear to be as effective as the mRNA vaccines, but may still prove helpful, and we must continue to follow the data. Production and distribution of the mRNA vaccines will be tough, so additional effective vaccines will help.
So should you or your patient get the vaccine?
That's for you to decide, based on the data and on what your physician or healthcare provider recommends. It's for your patients to decide based on informed consent. It is not your job to judge them or tell them what to do — offer evidence-based recommendations and up-to-date information, and let them decide for themselves. You can also lead by example and get the vaccine yourself. I think frontline workers and those at high risk should seriously consider getting vaccinated. For everyone else, that's a decision you (or they) have to make — but the data looks promising, and this could be our chance at returning to a state of semi-normalcy.
Clinical Pearls
Related Guides
References
- Moderna Announces Primary Efficacy Analysis in Phase 3 COVE Study.
- Pfizer and BioNTech Conclude Phase 3 Study of COVID-19 Vaccine Candidate.
- Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine (Pfizer), NEJM.
- Safety and Immunogenicity of the mRNA-1273 Vaccine in Older Adults (Moderna), NEJM.
- COVID-19: Vaccines to prevent SARS-CoV-2 infection (UpToDate).
- Facts about COVID-19 Vaccines (CDC).
- Understanding mRNA COVID-19 Vaccines (CDC).
- Vaccine Types (vaccines.gov).
- Allergic Reactions Including Anaphylaxis After the First Dose of Pfizer-BioNTech Vaccine (CDC MMWR).
- Interim Considerations: Managing Anaphylaxis After COVID-19 Vaccination (CDC).
- FDA: Track Vaccine Recipients for Facial Paralysis (WebMD).
- COVID-19 Vaccines and Pregnancy: Conversation Guide for Clinicians (ACOG).
- Vaccination Considerations for People who are Pregnant or Breastfeeding (CDC).
- Why COVID Vaccines are Falsely Linked to Infertility (WebMD).
- COVID-19: Evaluation and management of adults following acute viral illness (UpToDate).
- COVID-19: Long-term effects (Mayo Clinic).
- Herd immunity, lockdowns and COVID-19 (WHO).
- A New Strain of Coronavirus: What You Should Know (Johns Hopkins).
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