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Five Facts About the COVID-19 Vaccine

Experts address common questions about the COVID-19 vaccines and share why they are safe.

Doctor holding an ampoule of medicine and a syinge

The COVID-19 vaccine rollout is underway, bringing a sense of hope — as well as many questions about safety and who should get the vaccine. To help answer these questions, NewYork-Presbyterian and Weill Cornell Medicine experts address common concerns about the new Moderna and Pfizer-BioNTech COVID-19 vaccines and explain why they are safe.

Question 1: Can these vaccines give you COVID-19?

“It’s impossible for the vaccine to give you COVID-19 because it does not contain the live virus or even inactivated virus,” says Dr. Kristen Marks, an infectious disease specialist at NewYork-Presbyterian/Weill Cornell Medical Center. “It’s a common misconception and fear, but there is no possible way to contract COVID from the vaccine.”

Since the vaccine teaches our immune systems how to recognize and fight the virus, it can cause symptoms such as fever and body aches. These symptoms are normal and a sign that the body is building protection against the virus.

Question 2: The vaccine was developed so quickly. Is it safe?

“The data that’s been released and reviewed by the FDA shows that these two vaccines are very safe,” says Dr. Marks, who is also an associate professor of medicine in the Division of Infectious Diseases at Weill Cornell Medicine.

While the vaccines were created in less than a year, the technology that made them possible has been in development for years. “This achievement was possible because scientists leveraged what they learned from past outbreaks of similar coronaviruses and studies, and production of the vaccine was pursued simultaneously with clinical trials, rather than waiting for their completion,” Dr. Marks says.

She adds that none of the usual steps were skipped during the process; the clinical trials have been thorough and extensive, with thousands of participants, for the FDA to evaluate the vaccine’s safety and effectiveness.

Question 3: Can pregnant women get the vaccine?

Individuals who are pregnant may choose to be vaccinated, according to the CDC. The American College of Obstetricians and Gynecologists recommends that the COVID-19 vaccine not be withheld from those who are pregnant. “Based on how the vaccine works, we don’t think there’s any biologic reason that we should be concerned about its safety in pregnancy,” says Dr. Laura Riley, obstetrician and gynecologist-in-chief at NewYork-Presbyterian/Weill Cornell Medical Center.

“We do have lots of epidemiologic data which suggests that pregnancy plus COVID-19 is not a good mix. Pregnant women have had more admissions to the ICU, more mechanical ventilation, and more deaths, although the absolute number is low,” says Dr. Riley, who is also chair of the Department of Obstetrics and Gynecology at Weill Cornell Medicine.

While a doctor’s permission is not required to get the vaccine, talking to a healthcare professional may help guide women in making the decision. “I would suggest you talk to your OB or your midwife,” Dr. Riley says.

Question 4: Can people with allergies get the vaccine?

“The vast majority of people with a history of allergies can receive this vaccine safely,” says Dr. Jordan Scott Orange, an allergist-immunologist who is physician-in-chief at NewYork-Presbyterian Morgan Stanley Children’s Hospital. People who have severe allergies not related to vaccines or injectable medicines — such as nuts and other foods, pets, bee stings, latex, or oral medications — can get the vaccine.

The CDC recommends that people who have had a severe allergic reaction, specifically anaphylaxis, or an “immediate allergic reaction” (such as hives, swelling or wheezing within four hours) to an ingredient in a COVID-19 vaccine should not get it. People who are allergic to polyethylene glycol (PEG), which is in the vaccine, or polysorbate, which isn’t in the vaccine but is closely related to PEG, shouldn’t get the vaccine. Check with an allergist if you are unsure. Also, anyone who has a severe or immediate allergic reaction to the first COVID shot should not get a second dose, the CDC recommends.

Consult with an allergist beforehand if you’ve had an allergic reaction to another vaccine or to injectable medicine, says Dr. Orange, who is also chair of pediatrics at Columbia University Vagelos College of Physicians and Surgeons.

Question 5: I have medical problems and take medications. Can I safely get the vaccine?

The CDC recommends that people with certain underlying medical conditions be among the first priority groups to get vaccinated. People with a number of health conditions — including Type 2 diabetes, obesity, chronic kidney disease, and sickle cell disease — are at an increased risk of severe illness from COVID-19.

Dr. Susana Morales, a primary care physician at NewYork-Presbyterian/Weill Cornell Medical Center, notes that the trials testing the vaccines have intentionally included large numbers of people with diabetes, hypertension, obesity, and other health conditions. “A lot of the problems that many of my patients have are problems that the volunteers for the vaccine trials also had, and that was done on purpose,” says Dr. Morales, who is also an associate professor of clinical medicine at Weill Cornell Medicine. “They wanted to have a big cross section of the population.”

People with weakened immune systems and HIV may get the vaccine but should be aware of limited safety and efficacy data, the CDC says.

This story first appeared on NewYork-Presbyterian's Health Matters website.

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