A Deeper Dive Into Vaccines

Dr. Jean G. Gispen

Almost every visit to our clinic and every telehealth appointment ends the same way these days: “Let’s talk about the COVID vaccine.”

Some of my patients have scheduled the visit specifically to talk about the vaccines and their worries about taking them, or their hopes concerning how soon they can get a shot. Some patients are seeing me for dog bites or hypertension or Type 2 diabetes, and I am the one who brings up the topic of the vaccine.

To give the short answer first, I am 100 percent in favor of everyone age 16 or older taking the COVID vaccine, unless there is a medical reason not to.

Do I think the COVID vaccines are safe? Yes, I do, and I’ve written about that before. Millions of vaccines have been given safely. The main things I want to discuss here are allergies, pregnancy and breastfeeding.

Who should not take the Moderna or Pfizer COVID vaccine?

Allergic reactions

Both vaccines contain messenger RNA surrounded by a lipid globule that contains polyethylene glycol and other ingredients. Anyone who has had an immediate allergic reaction of any severity to a previous dose of an mRNA COVID vaccine or to polyethylene glycol should not take the vaccine.

An immediate allergic reaction includes any hypersensitivity-related signs or symptoms such as whelps or hives, angioedema (similar to hives but a little worse), trouble breathing (such as wheezing or stridor), or anaphylaxis within four hours of the vaccine.

Anaphylaxis is an exaggerated allergic response of the body to foreign proteins or other substances that often involves swelling, hives, low blood pressure and, in severe cases, shock. It can be life-threatening, but it is treatable.

Anyone who has had an immediate allergic reaction of any severity to polysorbates should not take these mRNA COVID vaccines for fear that the polysorbate-allergic person might cross-react with polyethylene glycol and have an allergic reaction.


Someone who is still in isolation with active COVID-19 illness should not take the vaccine. This person is in isolation, which means they should not interact with anyone, unless they go to an ER or hospital for medical care.

Antibody therapies

Anyone who has received antibody therapy as treatment for COVID-19 should wait at least 90 days after the antibody treatment before taking the vaccine. The infused antibodies – that are given through an IV – will be degraded or excreted by the body over time. It is thought that by 90 days, so few of them will remain in the body that they won’t interfere with developing an immune response to the vaccine.

Another vaccine

Anyone who has received another vaccine within the last 14 days should wait. The COVID vaccines were studied in situations where they were given singly, not simultaneously with other vaccines.

It is possible that another vaccine could interact with a COVID vaccine to change the effectiveness or safety of the COVID vaccine. Therefore, the COVID vaccine should be given at least 14 days apart from any other vaccines.

What about other allergic reactions?

A person who has had a severe allergic reaction or anaphylaxis to something other than vaccines or polyethylene glycol or polysorbates should take the COVID vaccine. The COVID vaccine does not contain eggs or latex.

If a person does have a history of anaphylaxis or severe allergies, that person will be observed for 30 minutes after the vaccination rather than the standard 15 minutes for people without a history of allergies.

Every vaccinating site will have someone on site to help if a person starts showing allergic symptoms. Every vaccinating site will have several EpiPens – an EpiPen contains epinephrine, which is given to fight the allergic reaction and to support blood pressure – and administrators at each site will know how to treat anaphylaxis.

The COVID vaccines have been found to be safe and effective for most people, so medical experts advise most people age 16 or older to get one. Adobe Stock photo

It makes sense to me that a person with a history of severe allergic reactions to shellfish or bee stings or contrast dye or anything might want to have her COVID vaccine administered in a clinic or hospital setting rather than in a drive-through setting, just in case treatment for anaphylaxis were to be needed. If a drive-through setting is chosen, the allergic person should have someone from her bubble in the car with her, so that if an allergic reaction begins to happen on the way home – after the 30-minute observation – the nonallergic driver can take the allergic person to an emergency room.

Anaphylaxis after the Moderna and Pfizer COVID vaccines is rare. As of Jan. 19, there have been 15 confirmed cases of anaphylaxis after the Moderna vaccine and 45 cases after the Pfizer vaccine, for rates of 2.1 cases per million Moderna vaccinations and 6.2 cases per million Pfizer vaccinations.

People with a history of allergies ask me whether they should take the mRNA COVID vaccines. I think they should. Anaphylaxis after the mRNA COVID vaccines is rare. It is treatable. COVID-19 is not rare. It is not always treatable.

Do the mRNA vaccines affect fertility?

They do not, in women or men. There is a rumor that antibodies against the spike protein might attack a protein in the placenta called syncytin-1. There is no data to support this rumor.

Should pregnant women get vaccinated?

The trials of the Moderna and Pfizer vaccines did not include pregnant or breastfeeding women, so it is not known for sure how these vaccines would affect such women.

Pregnant women who get COVID are at higher risk for severe illness than nonpregnant women. Obese pregnant women or pregnant women with gestational diabetes may be at higher risk yet. Though the overall risk of severe illness or death for pregnant women is low, pregnant women are more likely to need a ventilator or to die from COVID-19 than nonpregnant women.

Researchers have found a few cases where a pregnant woman with COVID-19 passed the infection to her fetus, but this seems to be rare. Some studies suggest an increased risk of preterm birth or stillbirth if the mother has COVID-19. Other studies have found this not to be true.

The mRNA COVID vaccines do not contain live virus. They are thought to be safe during pregnancy, but since no testing was done in pregnant women, this is not known. The mRNA vaccines are approved for use during pregnancy. Each woman should discuss the vaccine with her obstetrician/gynecologist.

One option is to take the vaccine as soon as it is available during the pregnancy. Another option would be to wait until the second trimester, when the natural risk of miscarriage is lower, and then take the vaccine. This choice entails being very careful to avoid exposure to COVID during the first trimester. A third option is to essentially isolate throughout the pregnancy and to take the vaccine after childbirth.

Flu shots and Tdap (the tetanus, diphtheria, whooping cough vaccine) typically are given during pregnancy. These vaccines must be separated from the COVID vaccine by at least 14 days.

Things to consider during the decision-making are risks to the mother and the fetus if the mother gets COVID, risks to the mother and to the fetus from the vaccine, and risks of catching COVID given the jobs and lifestyles of the mother, father and other people in the pregnant woman’s bubble.

What about breastfeeding?

A breastfeeding mother may take the COVID vaccine. She should discuss this with her pediatrician. Again, because the COVID vaccine does not contain any live virus, the vaccine would not cause COVID-19 in the mother or the breastfed infant.

No trials were done in breastfeeding women. Experts think that any mRNA particles that reached the breast milk would likely be digested by the baby and destroyed. One advantage of immunizing a breastfeeding mother with the COVID vaccine is that she would pass her antibodies to the baby through the milk, thereby providing antibody protection against COVID to the newborn baby.

How do I get a vaccine? Who is currently eligible?

To schedule a COVID vaccine when you are eligible, go to https://covidvaccine.umc.edu or to http://www.msdh.ms.gov. Another option is to call the COVID-19 Vaccine Call Center at 877-978-6453 or 601-965-4071. A third option is to look at the list of local providers on the Mississippi State Department of Health website, and then call a provider close to you to see if he has any available vaccines.

The people who currently are eligible for COVID vaccines are:

  • Everyone 65 or older,
  • Health care workers (this includes EMTs, paramedics, mental health workers, doctors, nurses and staff who work in hospitals or medical clinics),
  • People aged 18-64 with an underlying medical condition as listed here: cancer, chronic kidney disease, chronic obstructive pulmonary disease, Down syndrome, heart conditions (such as heart failure, coronary artery disease or cardiomyopathy), immunocompromise from a solid organ transplant, obesity or severe obesity (BMI greater than 30), pregnancy, sickle cell anemia, smoking, diabetes or other medical conditions determined by your medical provider.

What should I do while I wait for the vaccine?

While waiting for a COVID vaccine – and even after you’ve been vaccinated – remember to do what we’ve been doing for almost a year now. Wash your hands. Wear a mask that fits correctly over your mouth and nose – and double-masking may be more effective. Avoid indoor social gatherings and keep your distance from other people, staying at least 6 feet away. 

There will be limited vaccination doses available initially. Because people will be vaccinated in waves, it will take time to vaccinate enough of the population to stop the spread of COVID-19.

We can do this.

Dr. Jean G. Gispen is a staff physician at the employee health center within University Health Services at the University of Mississippi.