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Yes. The mRNA vaccines are especially safe: among the tens of thousands of people enrolled in the Phase III mRNA-Vaccine Clinical Trials, none have experienced severe adverse reactions. This is unheard of for vaccine clinical trials.
Vaccines are traditionally developed from one of several methods: (1) “live-attenuated” virus, made from virus that has been altered to decrease its virulence (harmful, infectious potential); (2) killed virus; (3) purified portions of virus, such as surface proteins. The mRNA vaccine contains none of those components, only the “message” used for our cells to produce a single protein to stimulate our immune system. These mRNA vaccines are the safest in vaccine history to date.
Learn more about how COVID-19 mRNA vaccines work.
No. mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept. This means the mRNA does not affect or interact with our DNA in any way. Instead, COVID-19 vaccines that use mRNA work with the body’s natural defenses to safely develop protection (immunity) to disease.
Learn more about how COVID-19 mRNA vaccines work.
No. None of the COVID-19 vaccines currently in development in the United States use the live virus that causes COVID-19. There are several different types of vaccines in development. The goal for each of them is to teach our immune systems how to recognize and fight the virus that causes COVID-19. Sometimes this process can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity. Learn more about how COVID-19 vaccines work.
It typically takes a few weeks for the body to build immunity after vaccination. This means it is possible a person could be infected with the virus that causes COVID-19 just before or after vaccination and get sick. This is because the vaccine has not had enough time to provide protection.
No. Vaccines currently in clinical trials in the United States won’t cause you to test positive on viral tests, which are used to see if you have a current infection.
If your body develops an immune response, which is the goal of vaccination, there is a possibility you may test positive on some antibody tests. Antibody tests indicate you had a previous infection and that you may have some level of protection against the virus. Experts are currently looking at how COVID-19 vaccination may affect antibody testing results.
Yes. While experts learn more about the protection provided by the COVID-19 vaccines under real-life conditions, it will be important for everyone to continue using all the tools available to us to help stop this pandemic, like covering your mouth and nose with a mask, washing hands often, and staying at least 6 feet away from others. Experts need to understand more about the protection that COVID-19 vaccines provide before deciding to change recommendations on steps people need to take that slow the spread of the COVID-19 virus. Getting a COVID-19 vaccine together with following CDC’s recommendations for how to protect yourself and others will offer the best protection from getting and spreading COVID-19.
For more information, visit considerations for wearing masks.
Yes, you should still get the COVID-19 vaccine, even if you have had COVID-19. There is not enough information currently available to say if or for how long after infection someone is protected from getting COVID-19 again; this is called natural immunity. Early evidence suggests natural immunity from COVID-19 may not last very long, but more studies are needed to better understand this.
The CDC has recommended that pregnant women and women planning to become pregnant may be offered the vaccine, in consultation with their health care provider.
After COVID-19 vaccination, you may have some side effects. This is a normal sign that your body is building protection. The side effects from COVID-19 vaccination may feel like flu and might even affect your ability to do daily activities, but they should go away in a few days. Your arm may be sore, red, or warm to the touch. You may experience a low-grade fever, headache, and just a general feeling of “not yourself”. These are signs that your immune system is doing exactly what it is supposed to, which is produce an immune response for you to have protection against this disease.
When you get your vaccine, you will get a link to get the “V-safe After Vaccination Health Checker” application for your phone. Through V-safe, you can quickly tell the CDC if you have any side effects after getting the COVID-19 vaccine. CDC may follow up by phone to get more information. V-safe will also remind you to get the second COVID-19 vaccine dose when needed.
The FDA has given full approval to the Pfizer vaccine for ages 16 years and older. In addition, Pfizer vaccine for ages 5-15, as well as Johnson & Johnson, and Moderna, have received emergency use authorization by the FDA. This means the vaccines have met the FDA’s rigorous scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization. Emergency use authorization allows a vaccine to become available prior to full approval in the case of public health emergencies.
The clinical trials for COVID-19 vaccines have involved tens of thousands of volunteers of different ages, races, and ethnicities. Clinical trials for vaccines compare outcomes (such as how many people get sick) between people who are vaccinated and people who are not. Because COVID-19 continues to be widespread, the vaccine clinical trials have been conducted more quickly than if the disease were less common. Results from these trials have shown that COVID-19 vaccines are effective. They have also shown no serious safety concerns after more than 8 weeks following vaccination. This is an important milestone, as it is unusual for adverse effects caused by vaccines to appear after this amount of time.