Answering readers’ vaccine questions
Information is changing rapidly as the COVID-19 pandemic sweeps the country, infection rates surge and dip and health care providers roll out the coronavirus vaccine across the country.
That’s what the Houston Chronicle’s COVID-19 Help Desk is here to get right. Every week, a Chronicle reporter will take readers’ questions about how the virus works and what to expect with the vaccine.
What’s in the ingredient list of the Pfizer and Moderna vaccines?
The U.S. Food and Drug Administration published the ingredients of both vaccines online as part of their emergency use authorizations. Pfizer-BioNTech’s vaccine includes mRNA, lipids, potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate and sucrose. Moderna’s vaccine includes messenger ribonucleic acid (mRNA),
lipids, tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate and sucrose.
The main component is the lipids (also known as fats), which provide a protective casing around mRNA to keep it from degrading before entering the body. Modified mRNA carries the blueprints for cells to create antibodies that attack SARSCoV-2. The rest are salts that help the body take in the vaccine and sugars to protect the vaccine from freezing when stored at cold temperatures.
As for what the vaccines don’t have, Dr. Megan Berman, a physician and faculty member at the Sealy Institute of Vaccine Sciences at the University of Texas - Medical Branch in Galveston, is keeping a list: “Neither of the vaccines contain eggs, gelatin, latex or any preservatives,” she said. “There are no aborted fetal cells in the vaccine.”
And no, there are no tracking microchips in there, either.
Should you get the COVID-19 vaccine if you’ve previously had an allergic reaction to an injection?
There are few reports of anaphylaxis in response to the COVID-19 vaccine, according to the Centers for Disease Control and Prevention — just 11 cases in 1 million vaccinations, to be precise.
Symptoms of swelling or difficulty breathing usually appear within half an hour, which is why medical providers monitor people for 15 to 30 minutes after inoculation.
People might hesitate to get the vaccine if they’ve had an allergic response in the past to the flu or shingles vaccines, but that’s not necessarily a reason to avoid the vaccine.
Instead, Berman suggests patients consult their allergist or primary care doctor before scheduling an appointment for the vaccine and ensure their vaccination site can treat them if they have a response.
“To put this in perspective, we can treat anaphylaxis,” Berman said. “All of these cases of anaphylaxis have actually been successfully treated. When you look at the lives taken by COVID-19 and you don’t know the longterm consequences for those who do survive, the risk/benefits just really seem to go toward vaccination.”
You may see some other side effects, such as a sore arm, fatigue or headache after the injection. They’re not signs of an allergic reaction, Berman said — just a sign that your body is creating the right immune response to COVID-19.
Does the COVID-19 vaccine have to be given in the arm, or can it go into another muscle?
Both the Pfizer-BioNTech and Moderna vaccines are intramuscular vaccines. Although designed for the arm or deltoid muscle, Berman said they can be administered in the thigh.
These vaccines target a kind of cell circulating through your muscle tissue called dendritic cells. When the cell receives the mRNA from the vaccine, it creates the protein response and carries it to the rest of the body’s immune system.
The resulting cells are then programmed to hunt down SARS-CoV-2 in the body, said Ben Neuman, a virologist at Texas A&M.
However, San Antonio-based Texas Biomedical Research Institute and U.K.-based Lancaster University are developing a nasal spray vaccine that is currently in clinical trials.
Why are scientists saying they don’t know if people who have been immunized can transmit the virus?
The clinical trials for the Pfizer and Moderna COVID-19 vaccines did not study whether people who had been immunized can transmit the virus.
Scientists are now checking trial participants for antibodies, active infections and whether they’re shedding virus particles.
“We don’t really know about the asymptomatic spread,” Berman said. “What we know about the current virus is that 40 percent of people are able to transmit it while they’re asymptomatic.”
Neuman told the Chronicle researchers may know the answer to that question in a year or two.
Are these vaccines on the market still effective against the more infectious U.K. strain?
The U.K. strain catching everyone’s eye is reportedly more infectious, but researchers say it does not cause more severe illness in the people who catch it.
Pfizer’s vaccine protects people from the new strain, Berman said.
“Because the Pfizer and Moderna are so similar, we can just assume that both of them are going to have the same effect,” she said.
At least one person in Harris County has been diagnosed with the new strain of virus.
Have a question for the Chronicle’s COVID-19 Help Desk? Email maggie.gordon@chron.com with COVID Help Desk Question in the subject line.