mature male receiving Covid vaccine
HealthMarch 12, 2021

COVID-19 vaccines: A primer for pharmacists

By: Erin Fabian, PharmD, BCPS

With so much misinformation about the COVID-19 vaccines and retail pharmacies joining this unprecedented public health effort, let's address common questions on efficacy, safety, and side effects.

Although they were fast-tracked, mRNA and viral vector vaccines are backed by rigorous science.

Most vaccines put weakened or inactivated forms of a pathogen or specific pieces of a pathogen into the body to trigger an immune response.

Current COVID-19 vaccines are either messenger RNA vaccines – also called mRNA vaccines – or viral vector vaccines. Both kinds of vaccines instruct the body's cells on how to make a harmless piece of the spike protein found on the surface of the virus that causes COVID-19. The viral vector vaccines use a modified version of a different virus to deliver the instructions. mRNA vaccines carry these instructions inside a special coating. Once the body's cells make the spike protein, it triggers the immune response to make antibodies, the proteins that protect people exposed to the virus.

Side effects and reactions are like what we see in common vaccines.

Pain, redness, or swelling at the injection site are the most common side effects following the first or second dose of a COVID-19 vaccine. People have also reported feeling tired or unwell, headaches, muscle or joint pain, fever, chills, upset stomach, and tender or swollen glands after receiving a dose of the vaccine. In most cases, these side effects have been mild to moderate.

Although rare, some people have experienced anaphylaxis - a severe, immediate allergic reaction which needs immediate emergency treatment. People who get the vaccine should be monitored for 15 to 30 minutes after getting a dose of a COVID-19 vaccine to make sure they do not develop a severe allergic reaction.

Side effects typically appear and subside within one to three days after injection. People tend to experience side effects more often after the second dose of the COVID-19 vaccine. If someone experiences side effects that persist beyond three days or if the redness or tenderness where they got the shot gets worse after 24 hours, they should contact their doctor or healthcare provider.

Some people have described a red, itchy, swollen, or painful rash where they got the shot that starts a few days to more than a week after the shot – some have called this "COVID arm". These people can get a second shot but should consider getting the shot in the opposite arm. It does not appear that having this type of reaction increases their risk of having a severe reaction to a second dose.

Looking for ways to improve population health management?

With innovative solutions that empower clinicians and analysts, we can help you address population health challenges across the continuum of care and beyond.

Explore Population Health Solutions
Population health

Some situations require additional attention.

For customers who had an immediate allergic reaction – a reaction that occurred within 4 hours – even if it was not severe, after getting their first shot, should not get a second dose. Advise them to speak with their doctor or healthcare provider.

People with pre-existing medical conditions can receive a COVID-19 vaccine so long as they have not had an immediate or severe allergic reaction to a previous dose. Anyone with concerns over pre-existing conditions or other allergies should talk to their doctor or healthcare provider before getting vaccinated.

You may also want to talk with pregnant or breastfeeding customers and with people who work in healthcare or in an essential or frontline work so they can make an informed decision about receiving a COVID-19 vaccine.

For the latest drug and vaccine guidance on COVID-19, visit our Lexicomp resources page.

Erin Fabian, PharmD, BCPS
Erin Fabian, PharmD, BCPS

Erin Fabian, PharmD, BCPS has been with Wolters Kluwer since 2007. She writes and maintains toxicology and adverse drug reaction content within UpToDate Lexidrug and provides clinical support for medical calculators.

UpToDate Lexidrug
Evidence-based drug reference solution used in the workflow and on-the-go
Clinicians choose UpToDate® Lexidrug™ for evidence-based drug information to support smart, safe medication decisions. Studies show that Lexidrug is the preferred drug reference solution for care teams.
Back To Top