Your COVID-19 vaccine questions answered


Published: March 8, 2021

By Sally Crocker

Diana Cervantes. Assistant Professor Biostatistics & Epidemiology

Dr. Diana Cervantes

More people are getting their COVID-19 vaccinations as more doses are being shipped to communities across the U.S. The Pfizer and Moderna vaccines are already well underway, and a third option, from manufacturer Johnson & Johnson, has now received FDA emergency authorization and is making its way to vaccine hubs around the country.

Spend a few minutes with an HSC expert to get answers to some of the top vaccine questions people are asking this week. Here, HSC epidemiologist Diana Cervantes, DrPH, MPH, Assistant Professor with the HSC School of Health and Director of the MPH Epidemiology Program, weighs in.

Q: What’s safe after the first dose? Do I need a second vaccine?
A: Dr. Cervantes: “Both the Pfizer and Moderna vaccines require two doses, plus a 10 to 14-day time period after your second vaccine, for the highest amount of protection. Once you get your first shot, you will be scheduled for your second one within 21-28 days, depending on which vaccine you received. The provider where you received your first dose will keep you updated and manage your appointment for the following dose. It’s highly recommended that you complete both doses for Moderna and Pfizer. The new Johnson & Johnson vaccine is administered as a single dose. While efficacy varies among the three vaccines, they are all considered extremely safe and important in helping us beat the coronavirus.”

Q: What should I know before my first vaccine?
A: Dr. Cervantes: “To maximize your protection, the CDC recommends that you not receive any other immunizations at least 14 days before or 14 days after your COVID vaccine, unless otherwise determined by your healthcare provider. It’s also best to hold off on taking pain relievers like Advil, Tylenol and others prior to your vaccine. Taking them afterward as needed is generally considered fine, but definitely discuss this with your healthcare provider.”

Q: Can I choose my vaccine?
A: Dr. Cervantes: “Not likely. The vaccine you receive will depend on availability, timing and location. They have all been shown to help protect you from the severe outcomes of getting infected with the virus, like hospitalization.”

Q: Does it matter if my doses are from two different manufacturers?
A: Dr. Cervantes: “It does matter. As studies to determine the efficacy of the vaccine did not interchange between manufacturers, we cannot really say how much protection the vaccine may offer if the doses differ by vaccine type (Moderna vs. Pfizer). The CDC also recommends that you receive your second COVID vaccination at the same place, with the same provider, where you received your first dose. You’ll be given a vaccination card at your first visit, indicating which type you’ve been given.”

Q: Are there side effects?
A: Dr. Cervantes: “As with any vaccine, there could be side effects. You might experience fever, chills, tiredness, headache or soreness on the arm where you received your shot, which are all normal signs that your body is building protection. Many people have reported no side effects or only a mild reaction so far. Others have reported a little more response with the second Moderna dose. Serious side effects, though, are extremely rare.

If you experience any symptoms such as cough or shortness of breath days after your appointment, this is likely not due to the vaccine, but you may have COVID-19 or another respiratory infection that started before you were vaccinated and aware. If you experience any type of respiratory symptom, be sure to contact your doctor. You cannot get COVID infection from the vaccine as it does not contain the virus, only instructions for your body to create a small part of the virus to stimulate your immune response.”

Q: Is there protection between doses?
A: Dr. Cervantes: “The first may give you some protection, but it’s the second dose that really enhances that protection.”

Q: Once I complete both shots, am I home free?
A: Dr. Cervantes: “In certain situations in which transmission of the virus is low, such as indoor visits with others who are fully vaccinated (at least 14 days after their last required dose), or when visiting limited family members who are generally healthy but are not vaccinated, masks and physical distancing may not be necessary. But, as with all other vaccines, the COVID vaccines do not offer 100% protection. We are still learning a lot about how well the vaccines protect you from being able to spread the virus to others if you get a very mild infection. So, at this point until we learn more, it’s definitely recommended to keep the mask and continue physical distancing in high risk settings or situations such as healthcare facilities or around those at high risk for severe illness or hospitalization. Wearing masks, avoiding crowded indoor spaces and staying 6 feet apart from people outside your immediate household are still considered important tools in helping us beat this pandemic. So don’t make major changes to your behavior yet, and continue to follow CDC and public health guidance.”

Q: Do I need a shot if I’ve already had COVID?
A: Dr. Cervantes: “Yes, as reinfection is definitely possible. If you’ve recently tested positive or been exposed to someone who has the virus, however, you should not go to a vaccine site until your isolation or quarantine period has passed, to avoid exposing others.”

Q: What if I have certain allergies?
A:
Dr. Cervantes: “You will be asked about this and advised by your vaccine provider, so be sure to let them know … and don’t be afraid to ask questions if you’re concerned.”

Q: What happens after my vaccination?
A:
Dr. Cervantes: “For the first 15-30 minutes afterward, you’ll be asked to wait in an area accessible to healthcare providers to ensure you’re safe and don’t experience a serious reaction. This is required by the CDC at all vaccination sites and helps protect you. You’ll be given guidance on any follow up needed and what to do if you experience any concerning symptoms once you get home.”

Q: How do I sign up?
A: Dr. Cervantes: “The Texas Department of State Health Services website provides details on vaccine allocations and a full list of providers across the state.”

Q: Anything else I should know?
A: Dr. Cervantes: “It’s been a long year, but the good news is that we are getting closer every day in the battle against COVID-19. The COVID vaccines are a safe and highly effective defense against the disease. If you have access to a vaccine and you’re eligible, you should definitely get it.”