As we in the U.S. struggle to set up systems for the rapid administration of SARS-CoV-2 vaccinations, what do nurses need to know about these vaccines?

Two vaccines have received emergency use authorization (EUA) in the U.S.—one manufactured by Pfizer/BioNTech, the other by Moderna. (A third, manufactured by AstraZeneca, is likely to receive EUA by April.) New, more efficient vaccine technologies along with a huge financial investment by the U.S. government have produced these products in a much shorter time frame than has been typical for other vaccines.

Currently available vaccines.

The two vaccines that are available now are messenger RNA, or mRNA, vaccines. This type of vaccine has been developed and studied for decades for possible use in preventing influenza, Zika, and other infectious diseases. Human mRNA is a strand of genetic material used for cell building and maintenance. For SARS-CoV-2 vaccines, mRNA based on part of the SARS-CoV-2 genome is synthesized and standardized in a lab.

When administered in a vaccine, this mRNA delivers to our cells the instructions  to replicate a “spike protein” found on the surface of the SARS-CoV-2 virus. (Important to know and tell patients: The mRNA never enters the nuclei of our cells, and can’t be incorporated into our own DNA.) After a cell follows these instructions and “posts” the spike protein replica on its surface, the immune system recognizes it as foreign and reacts by producing antibodies along with a supply of “memory” T-lymphocytes and B-lymphocytes that will recognize the virus if they encounter it in the future.

The Pfizer/BioNTech vaccine, for people ages 16 years and older, is given as two 0.3 mL IM injections 21 days apart. This vaccine has complicated “deep freeze” storage requirements (neg 112 to neg 76 degrees F). It can be stored undiluted in a refrigerator for up to five days. After dilution, it can be maintained at refrigerator or room temperature (up to 77 degrees F) but must be used within six hours. For detailed information about storage and handling, refer to storage and administration information from the manufacturer.

The Moderna vaccine, for people ages 18 and older, is given as two 0.5 mL IM injections spaced 28 days apart. While it can be stored at common freezer temperatures (neg 13 to 5 degrees F), and can be refrigerated at 36 to 46 degrees F for up to 20 days prior to first use, it too has complicated dilution and storage instructions, so refer to the manufacturer’s website.

Adverse effects.

According to the CDC, both vaccines can cause local or systemic side effects in the first day or two, like what many people may experience after other vaccines. They include pain, swelling, or redness at the injection site, fever, chills, fatigue, or headache. Systemic side effects may be more common after the second dose. Neither vaccine contains eggs, preservatives, or latex.

As with any immunization, allergic reactions can occur, and the vaccine administration site should have emergency supplies and equipment available in case of anaphylaxis; many sites ask recipients to stay on site for 15 to 30 minutes to ensure that there’s no severe reaction. A second dose should not be administered if the recipient had an allergic reaction to their first dose of vaccine. People who are allergic to polyethylene glycol (PEG) or polysorbate should not be vaccinated. (There is no polysorbate in either vaccine, but polysorbate is closely related to PEG, which is in the vaccine.)

Points of interest regarding these vaccines:

  • The CDC notes that antibody production takes “a few weeks,” so as with the influenza vaccine, it’s possible for people to develop COVID-19 despite vaccination if they were infected just before or after they received the vaccine.
  • After the second injection, these vaccines have been shown to prevent illness from COVID-19 about 95% of the time. However, it’s not known whether they prevent asymptomatic infection and its possible transmission. Therefore, recipients should continue to wear their masks, be aware of physical distancing, avoid gatherings (especially indoors), and keep their hands clean.
  • Vaccine recipients should receive a “vaccination card” to document their first dose of vaccine, and as a reminder about when to return for a second dose.
  • All viruses mutate, and mutations don’t necessarily cause significant functional changes in a virus. Right now, the variant forms of SARS-CoV-2 don’t appear to be “vaccine resistant.”
  • It’s not yet clear how long SARS-CoV-2 immunity lasts or whether it is the result of SARS-CoV-2 infection or vaccination. It’s possible that, as with other vaccines, we may need periodic boosters of any SARS-CoV-2 vaccine.