VACCINE ANSWERS
An infectious disease specialist who received the shot explains the safety of COVID vaccines.
The COVID-19 vaccines have been touted as the beginning of the end of the deadliest pandemic in recent U.S. history. But many residents are still wondering: Are the vaccines that were developed in record time safe?
In December, the U.S. Food and Drug Administration approved emergency use of COVID-19 vaccines made by Moderna and PfizerBioNTech. Unlike many other vaccines that use a killed or weakened virus, these new COVID-19 vaccines harness a groundbreaking technology called synthetic messenger RNA — mRNA for short — that directs cells to produce proteins that trigger the immune system to create antibodies. Those antibodies fight the real virus if a person becomes infected.
We interviewed Dr. Ruth Berggren, an infectious disease specialist at UT Health San Antonio, to learn more about the vaccines’ safety.
She served on a UT Health working group that examined the safety of the Pfizer vaccine and considered how it should be distributed among front-line health care workers.
She also received the vaccine herself in December — and has since been “feeling just fine.”
This interview has been edited for length and clarity.
Let’s start by talking about what we know about the safety of the Moderna and Pfizer vaccines for the general population.
Anything we know is clearly limited to the sizes and the distributions of the study populations for the Pfizer and Moderna vaccine trials. With any drug and with any vaccine, there are always post-marketing findings. When you expand from populations of 30,000 to 40,000 people to 30 million to 40 million, you’re going to expect that you’re going to find some
things that you hadn’t found previously. That having been said, the safety concerns have been pretty minor.
What safety concerns have come up so far?
The biggest is the possibility of having a severe allergic reaction to one of the vaccine components and a severe allergic reaction we call anaphylaxis. That’s the allergic reaction where your throat closes up, and because of swelling back in your throat area, you can’t breathe. Because the vaccine is being given in a closely monitored medical setting, we treat people who are showing even a glimmer of an anaphylactic reaction with appropriate treatments that can include antihistamines, steroids and then even epinephrine if there’s a real danger of the throat closing off.
That’s the big concern. What are people being allergic to that’s causing this? The ingredients of the vaccine are publicly available in multiple places including FDA and CDC documents. Probably the most important ingredient is polyethylene glycol, or PEG, which is not a weird or new compound. Polyethylene glycol is what is in the prep that people take when they’re going to go for a colonoscopy, that liquid stuff that you drink. It’s been used chemically to modify drugs that we give people, such as interferon. So this is not a new thing. There are decades and decades of safety information about it, but like everything else, some people could become allergic, just like some people can become allergic to a bee sting.
Can you talk about the safety of these vaccines for people who are immunocompromised, such as people who have lupus or Type 1 diabetes?
I want to make it clear this vaccine is not harmful for people whose immune system is weakened for one reason or another. The issue is that people who are immunocompromised need to know that their response to the vaccine may not even come close to being as protective as it is for other people. If my immune system is weak and I get vaccinated, I’ll probably mount some immune response, but I might not mount enough of one to fully protect me from getting infected or to fully protect me from severe disease.
We have that note of caution, and people get asked prior to being vaccinated, “Are you pregnant? Are you immunocompromised?” so that they can be informed of what this vaccine could or could not do for them.
It’s important for the public to know that in the Pfizer vaccine trial, people with wellcontrolled HIV, as well as people with controlled hepatitis B and hepatitis C, were included. And there was no problem in people with well- controlled HIV.
Does that also apply to folks with other chronic conditions, such as high blood pressure or diabetes?
Right. In fact, people who have diabetes or hypertension should be prioritized to get the vaccine. Why? Because people with diabetes and hypertension are the ones that are getting severely ill with COVID-19 and more likely to die. So those are the very people that we would put ahead of others to get vaccinated so we can make sure that they’re protected.
Can you talk about what we know about the safety of these vaccines for people who are pregnant or breastfeeding?
The Society for MaternalFetal Medicine got up front with a statement recommending that pregnant women who are at risk for getting COVID-19 should not be prevented from getting the vaccine and that they should be allowed to make the decision in conjunction with their doctor. There is no evidence that the vaccine harms the fetus, but we also don’t have any large-scale evidence of intentionally giving this vaccine to pregnant women to watch what happens.
It needs to be an individualized decision. If a pregnant mom is on the front lines of health care — let’s say she is intubating patients who have SARS-CoV-2 infection — that is a high-risk situation. If you add on that that pregnant woman may have gestational diabetes or hypertension — some of the risk factors for a bad COVID-19 disease outcome — it would be a bad thing to prevent such a woman from getting vaccinated. She should be allowed to have access to it.
It was reported that some women got pregnant over the course of the Pfizer vaccine trial. Can you talk about what we learned through that?
There were around 23 pregnancies that happened in spite of the fact that enrollees were instructed to take precautions to not get pregnant during the Pfizer vaccine trial. In a sense, if you want to take the silver lining or a glass-half-full attitude towards this issue, at least we know that there doesn’t seem to have been a problem with fertility, which has been an issue that’s been raised really by the internet — not by scientists. But clearly if women unintentionally got pregnant while they’re on the Pfizer vaccine study, that would argue against there being any impact on fertility.
Moreover, there have been no adverse outcomes reported so far as the Pfizer vaccine continues to be studied. So we have an extremely limited number of pregnant women who have been vaccinated, and this is why there’s not a full-blown guidance for them to get it. It’s simply that we lack data. However, people need to know we don’t have negative data.
Can you address some of those myths you’ve seen circulating on the internet?
The first is that this vaccine is going to mess with my DNA and it’s going to change my genetic structure for the rest of my life. Here’s what you need to understand about the biology of the mRNA vaccine: The mRNA is an encoded message that gets slipped into an envelope, which is made out of lipid or fatty substance. That fatty lipid envelope permits the vaccine to get onto a cell, merge with the cell membrane, and then the mRNA gets delivered into the inside of the cell in a place called the cytoplasm, if you remember from your high school biology.
Now the cytoplasm isn’t just an open swimming pool. The cytoplasm is highly compartmentalized, and there’s a great big separation between the cytoplasm and the nucleus. The nucleus of the cell is a highly protected area, which contains our DNA. That’s where our genetic code is, OK? The mRNA does not go into the nucleus.
What the mRNA message does, it stays in the cytoplasm and it gets directed towards the ribosomes, which are the places where proteins are made. I like to use the analogy of a 3D printer: The mRNAs have a message for your 3D printer — your ribosome — for what kind of protein the ribosome should make. That protein that’s being encoded is the spike protein from the coronavirus.
What other concerns have you heard from people that you’d like to address?
People were questioning whether there was a possibility that the spike protein could cause women to miscarry because of what they call homology (similarity in structure) between the spike protein and Syncytin-1, which is a protein that is involved in the development of the placenta.
A patient sent me a message through my chat saying, “We’re reading this, and could you tell us if this is a problem?” I’ve already told you why people shouldn’t be concerned about it because people actually got pregnant while getting the coronavirus vaccine protocol from Pfizer.
There’s no reason to think that because little pieces of one protein resemble little pieces of another protein that the antibodies generated on the first protein are going to be specific to the second protein. Here’s an analogy: It would be like saying, you’re looking at two different types of shelter, and one is a log cabin in the wilderness and one is the White House. Let’s say that you had a smart weapon that was being targeted to destroy the log cabin or destroy the White House. What people need to know is that our immune system is super smart and it’s not so random that it would just start destroying anything that had the same function. It’s going to be very specifically targeted to the exact size and shape of the danger signal.