Vaccination is a safe and effective way to prevent disease. Vaccines save millions of lives each year. When we get vaccinated, we aren’t just protecting ourselves, but also those around us.

When a person gets vaccinated, they are less likely to get a disease or pass the germ on to other people. When more people get vaccinated there are fewer people left for a germ to infect so it is harder for the germ to spread. This is called community immunity or “herd immunity.” Herd immunity is important because it protects people who can’t get the vaccine, for example, because they are too young or are very sick.

Vaccines work by preparing the body’s immune system to recognize and fight off germs. They reduce your risk of getting a disease by working with your body’s natural defenses to build protection.When you get a vaccine, your immune system responds. It:

• Detects the invading germ, such as a virus or bacteria.
• Makes antibodies. Antibodies are proteins produced naturally by the immune system to fight disease.
• Remembers the disease and how to fight it. If you are exposed to the germ after getting the vaccine, your immune system can quickly destroy it before you become sick.

Our immune systems are designed to remember. After we get one or more doses of a vaccine, we are protected against the disease for a period of time. This is what makes vaccines so effective. Instead of treating a disease after it happens, vaccines can prevent us from getting sick in the first place.

No. None of the COVID-19 vaccines being developed in the United States have the virus that causes COVID-19 in them. Sometimes people get a fever or feel tired for a day or so after getting a vaccine. These symptoms are normal and are a sign that the body is building immunity. You can learn more about how COVID-19 vaccines work at this CDC website.

It usually takes a few weeks for the body to build immunity after vaccination. If a person got infected with the virus that causes COVID-19 just before or just after they got a shot they could still get COVID-19. This is because the vaccine has not had enough time to provide protection.

No. Vaccines won’t cause you to test positive on a viral test (like the swab test) that looks for current COVID-19 infection. You may test positive on some antibody tests. This is because one of the ways that vaccines work is to teach your body to make antibodies.

See the public health testing webpage to learn more about COVID-19 tests.

Around the world over 50 COVID-19 vaccines are being tested in humans. Only a few vaccines are being studied in volunteers in large-scale (phase 3) clinical trials in the United States to see how well they work. See the guidance on clinical and vaccine trials to learn more about phase 3 studies.

Most of the COVID-19 vaccines that are being tested are given in two doses a few weeks apart. It is important to get the same kind of vaccine for both shots.

No. Your doctor or pharmacy may charge a fee for giving the vaccine, but it should be covered by public and private insurance companies. People without health insurance can get COVID-19 vaccines at no cost. There are no out-of-pocket payments.

There won’t be enough for everyone right away. Plans have been made to spread these limited vaccines in a fair, ethical, and transparent way. Healthcare workers and people living in long-term care facilities (such as nursing homes) will be offered the vaccine first. The goal is for everyone to be able to easily get a COVID-19 vaccination as soon as large quantities are available; this may take a few months.

We need to do as much as we can to stop the pandemic. Vaccines boost your immune system so it will be ready to fight the virus if you are exposed. Other steps, like masks and social distancing, help lower your chance of being exposed to or spreading the virus. Together, these tools offer the best protection from COVID-19.

Yes, you do need the vaccine even if you have had COVID-19. We don’t yet know how long you are protected after you have had COVID-19, so it is important to have the vaccine to strengthen your immunity.

Yes! It is likely that the viruses that cause influenza (flu) and COVID-19 will both be spreading this winter. A flu shot only protects you from the flu, but at least it means you won’t run the risk of getting flu and COVID-19 at the same time. This can keep you from having a more severe illness. Getting a flu vaccine now is more important than ever. If you are likely to get the COVID-19 vaccine soon, ask your doctor about the best time to get the flu shot. This is because the two vaccines may have to be given several weeks apart.

You should cover your mouth and nose with a face covering when around others, avoid close contact with people who are sick, practice physical distancing, and wash your hands often. See guidance for reducing your risk. You should continue to do this even after you get a vaccine.