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The Pfizer COVID-19 vaccine is now available for ages 12 and older. Click here to schedule an appointment.


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The Pfizer and Moderna COVID-19 vaccines currently available require two doses.

Here are six things you need to know about getting your second dose.

1. It is common for a vaccine to require two doses.

Several vaccines require multiple doses to receive maximum protection from a vaccine including many you received as a child such as diphtheria, tetanus, pertussis and measles. The first dose starts to build protection, and the second dose gives you the most protection the vaccine can offer. If you do not receive both doses of the currently available COVID-19 vaccines, you will not have the 95 percent effectiveness reported in the available data.

2. The timing of your second dose depends on which vaccine you received.

If you received the Pfizer vaccine, your second shot will be three weeks later (21 days). If you received the Moderna shot, your second shot will be four weeks later (28 days). You should try to get your second shot as close to 21 days or 28 days following the first shot (depending on which shot you received).

However, a second dose is considered by the Centers for Disease Control and Prevention (CDC) as “valid” if received one to four days before the recommended timing of a second dose.  In other words, if you receive the first dose of the Pfizer shot on Jan. 10, it is okay if you receive your second shot Jan. 27-30. It is also acceptable to receive the second dose later than the recommended time. So if you receive the first dose of the Pfizer shot on Jan. 10, it is okay if you cannot get your vaccine exactly 21 days later.

If you have a My UNC Chart account, you can find information about how to reschedule or cancel your appointment here.  If you do not have a My UNC Chart account, please call the location where you are scheduled at to reschedule or cancel your appointment.

3. You will make your appointment for your second dose of the vaccine at your first COVID-19 vaccine appointment.

UNC Health entities are receiving both Pfizer and Moderna vaccines. The brand of vaccine you receive will depend on what is given at the location where you receive your vaccine. You must receive the second dose from the same company (Pfizer or Moderna) as your first shot, so you must receive your second dose at the same location you receive your first vaccine.

If you need to change your appointment for your second dose, you can do so in My UNC Chart, or if you do not have a My UNC Chart account, please call (984) 215-5485.

4. Second doses have been reserved for those scheduled to receive them.

Although vaccine supplies are limited, UNC Health vaccine sites coordinate and work with our pharmacy to maintain the appropriate supply for each week for second doses. Please be rest assured, your second dose will be available when it is time for your appointment.

5. Side effects are more common with the second dose compared to the first dose.

Side effects can be more common after the second dose.  However, side effects are usually mild to moderate and last only one to three days. In the trials of these vaccines, most people had no reactions to either the first of second dose, other than soreness at the site of the injection. If you have pain or discomfort, talk to your doctor about taking an over-the-counter medicine, such as ibuprofen or acetaminophen.

6. It is important to continue following all safety guidelines after your second dose.

It takes time for your body to build up protections against COVID-19 after your vaccine. If you get a two-dose vaccine (Pfizer or Moderna), you are considered to be fully protected from COVID two weeks after your second dose. If you get a single-dose vaccine (Johnson & Johnson), you are considered fully protected two weeks after your vaccine.  The CDC has issued guidance for what people who are fully vaccinated can do. In general, fully vaccinated people can be indoors and outside without a mask, if they choose, except in certain places such as healthcare, childcare, and correctional facilities.

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