Facts About COVID-19 and the Vaccines

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COVID-19

What is COVID-19 and why is vaccination so important?

COVID-19 is an infectious disease caused by the SARS-CoV-2 coronavirus.

There’s no way to know how COVID-19 will affect you. Most people have a mild case, but it can cause serious illness and death.

COVID-19 has killed more than 1,040,000 people in the United States, making it a leading cause of death.

Some people develop long COVID, where they have symptoms that last for weeks or months.

Getting a COVID-19 vaccine reduces the risk that you’ll:

  • Get seriously ill, require hospitalization, or die from COVID-19.
  • Spread the disease to others, putting their health and lives at risk.

The more COVID spreads, the more it can mutate, or change, creating variants. Highly contagious variants have caused nearly all COVID-19 infections in the United States for much of the pandemic. 

Vaccinating as many people as possible is the best way to reduce:

  • The spread of COVID.
  • The chance of future variants developing that may be more dangerous.

How can I protect myself and others from COVID until I get vaccinated?

If you’re not yet vaccinated, your best protection is to wear a well-fitting mask over your nose and mouth inside public places when the COVID risk to your community is high.

If you’re at higher risk of getting very sick from COVID, you can also protect yourself by:

  • Keeping at least 6 feet away from people who don’t live with you.
  • Avoiding crowds and poorly ventilated spaces.
  • Washing your hands often with soap and water for at least 20 seconds or using hand sanitizer with at least 60% alcohol if you don’t have soap and water.

Getting vaccinated

Who can get a COVID-19 vaccine and where can I get vaccinated?

Everyone ages 6 months and older in the United States should get a COVID-19 vaccine.

The vaccines are free for everyone—citizens and noncitizens alike, regardless of your immigration status.

You don’t need health insurance. And many vaccine providers don’t require any forms of ID.

Vaccines are available from pharmacies, doctors’ offices, community health centers, and many more locations. Most people live within 5 miles of a vaccination site.

You have 3 ways to find vaccines near you:

How are COVID-19 vaccines given?

The available COVID-19 vaccines are given as a shot in the upper part of your arm. Infants and toddlers may receive vaccines in their thighs.

The process is quick and practically painless, because the needle is very thin and the dose is small.

Which COVID vaccine can I get?

Everyone 6 months or older can get either the Pfizer-BioNTech or Moderna vaccine.

People 12 and older can also choose to get the Novavax vaccine.

Johnson & Johnson’s Janssen vaccine is available in limited situations for people ages 18 and older, such as for those who can’t get the other vaccines for health reasons.

How many vaccine doses do I need for the best protection?

The number of doses you need to stay up to date with your vaccines depends on your age and which vaccine you get.

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Vaccines and Doses Infographic

For males ages 12–39: You may benefit from waiting longer between the 1st and 2nd doses of your primary vaccination series. Talk to your health care or vaccine provider.

For vaccinated people 12 and older: Updated vaccines are available to help protect against Omicron.

It doesn’t matter which COVID vaccine you got for your primary vaccination series (Pfizer-BioNTech, Moderna, Novavax, or Johnson & Johnson’s Janssen) or how many boosters you’ve already gotten; get your updated vaccine 2 months after your last dose.

If you recently had COVID, you should wait 3 months from when you got sick to get your updated vaccine.

Teens 12–17 can get Pfizer-BioNTech’s updated vaccine.

People 18 and older can get either Pfizer-BioNTech's or Moderna’s updated vaccine.

For people with compromised immune systems: Because you’re less able to fight infections, you may need more than these recommended doses. Talk to your health care provider.

Vaccine safety

Are COVID-19 vaccines safe?

Yes. The COVID-19 vaccines available in the United States meet the FDA’s and CDC’s very high safety standards.

Hundreds of millions of people in the United States have safely received COVID-19 vaccines under the most intense safety monitoring in U.S. history.

Serious side effects and allergic reactions are extremely rare, occurring in only a small number of people.

There is no evidence that COVID-19 vaccines will cause long-term health problems, such as infertility or cancer.

All COVID-19 variants are greater threats to you than any risk from vaccine side effects.

COVID-19 can leave you with heart and lung damage and other conditions that require long-term treatment.

Vaccines are much safer paths to immunity than the disease itself.

If you’re allergic to any ingredients in the vaccines, your health care provider can help you decide if it’s safe for you to get one of the vaccines.

Are COVID-19 vaccines safe for children?

COVID-19 vaccines were rigorously tested in thousands of children before authorization by the FDA. They were shown to be safe and effective during the clinical trials.

Children had the same kinds of temporary side effects from vaccines as adults. Side effects during the clinical trials were usually mild and went away on their own in a few days.

For more on COVID-19 vaccines for children, see our Frequently Asked Questions From Parents/Guardians About COVID-19 and the Vaccines.

What safeguards are in place to make sure COVID-19 vaccines are safe?

Before the FDA makes vaccines available to the public:

  • Scientists must test the vaccines in medical studies, called clinical trials, with thousands of participants. These studies compare what happens to people who get the vaccine with people who don’t get the vaccine.
  • More than 100,000 volunteers from diverse populations took part in clinical trials for the available COVID vaccines.
  • FDA scientists review the data from the medical studies and inspect the places where the vaccines are made before they authorize or approve the vaccines for public use.

Even after vaccines are available to the public:

  • FDA and CDC scientists closely monitor how the vaccines are made and given, to identify any safety issues.
  • FDA and CDC scientists closely review any reports of side effects or reactions and share these facts with the public.

How can COVID-19 vaccines be safe? They were developed so fast.

COVID-19 may be a new disease, but vaccines aren’t new.

Scientists were able to quickly develop safe, effective COVID-19 vaccines by applying many years of vaccine experience and advances in technology.

Also, the National Institutes of Health had been working on a coronavirus vaccine before the pandemic and was able to use that experience in developing a COVID-19 vaccine.

Importantly, no one has cut any corners or skipped any steps that affect vaccine safety in the development, testing, authorization, and approval of COVID-19 vaccines.

Are COVID-19 vaccines approved by the FDA?

The FDA has authorized multiple COVID vaccines for emergency use. They were authorized for use only after scientists concluded they meet the FDA’s very high standards for safety and effectiveness.

The FDA has fully approved the following vaccines after thoroughly evaluating additional data on their safety and effectiveness and inspecting where and how they’re made:

  • The Pfizer-BioNTech COVID vaccine for people ages 12 and older.
  • The Moderna COVID vaccine for people ages 18 and older.

Will the shot make me sick?

You can’t get COVID-19 from the vaccines because they don’t contain the virus that causes the disease.

Your arm might feel sore after you get your shot. You might also experience flu-like symptoms, such as fever, headaches, body aches, and tiredness.

These are normal signs that your immune system is responding to the vaccine. Although these side effects may be unpleasant, you’re not actually sick. And they last a few days at most.

What are the more serious side effects of COVID-19 vaccines?

Serious side effects from any vaccine, including the COVID-19 vaccines, are very rare.

It’s also highly unlikely that the vaccines will cause any long-term health problems, such as cancer.

A very small proportion (not even 0.0001%) of vaccinated people have experienced the following in the hours and days after vaccination with one or more of the vaccines:

  • Anaphylaxis—an allergic reaction that, if it happens, is likely to occur within minutes of vaccination. Vaccination sites are prepared to handle any rare cases of anaphylaxis that occur.
  • Myocarditis and pericarditis—two kinds of heart inflammation that, if they happen, are likely to occur within several days of vaccination.
  • Guillain-Barré syndrome—a rare autoimmune disorder that, if it happens, is likely to occur within the first couple of weeks after vaccination.
  • Thrombosis with thrombocytopenia syndrome—an extremely rare blood-clotting condition that, if it happens, is likely to occur within the first couple of weeks after vaccination.

If any of these unlikely reactions happen, health care providers know how to treat them.

The fact that we know of these extremely rare cases shows that the FDA and CDC’s vaccine safety monitoring systems work and catch even the rarest reactions.

Are COVID-19 vaccines safe for people who are pregnant, want to become pregnant, or are breastfeeding?

Yes. Getting a COVID-19 vaccine can protect you against severe illness from COVID-19 and help keep your baby safe.

COVID-19 can be a dangerous disease during pregnancy and increases the risk of preterm birth. It might increase risks for other adverse pregnancy outcomes.

Vaccination against COVID-19 does not lead to complications during pregnancy.

There’s also no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems in women or men.

And there’s no reason to put off getting vaccinated if you’re on your period.

CDC recommends COVID-19 vaccination as soon as possible for all people who are pregnant, trying to become pregnant, wanting to become pregnant someday, or breastfeeding.

What’s in COVID-19 vaccines?

The active ingredient in the Pfizer-BioNTech and Moderna vaccines is a molecule with instructions for your cells to create the coronavirus spike protein. The active ingredients in the Novavax vaccine are copies of the coronavirus spike protein and an extract from the soapbark tree.

How do COVID-19 vaccines work?

The COVID vaccines available in the United States either directly introduce your immune system to the spike protein found on the surface of the coronavirus or give your cells the instructions to make the spike protein.

Your immune system sees the spike protein as an invading germ and reacts by creating cells that will be ready to identify and attack the coronavirus if you’re exposed to it. But the vaccines don’t contain the coronavirus, so you can’t get COVID from them.

Once your immune system is introduced to the spike protein, your body breaks down the vaccine ingredients and gets rid of them.

At no point do the vaccines change or interact with your DNA.
 

Vaccine effectiveness

How effective are COVID-19 vaccines?

All available COVID-19 vaccines are very effective.

They are highly effective against severe illness, hospitalization, and death due to COVID-19.

Why should I get vaccinated if I can still get infected with COVID-19?

Your chance of getting COVID if you’re unvaccinated is much higher than if you’ve gotten all recommended doses of a COVID vaccine. You’re also much more likely to get seriously ill from COVID if you’re unvaccinated.

If you’re up to date with your COVID vaccines and the virus enters your body (infects you), your immune system will quickly recognize the virus and will work to keep it from doing real harm.

That’s why most people who get infected with COVID despite being up to date with their vaccines have no symptoms or only mild-to-moderate illness.

Most people getting severely ill, needing hospitalization, and dying from COVID are unvaccinated.

Will COVID-19 vaccines prevent me from infecting others?

COVID-19 vaccines reduce the likelihood that you’ll get and be able to spread COVID-19.

But if you’re infected with a very contagious variant, you can spread the virus to others, whether you’re vaccinated or not.

That’s why both vaccinated and unvaccinated people should wear well-fitting masks inside public places when the COVID risk to your community is high.

Do I need to get a COVID-19 vaccine if I’ve already had COVID-19?

Yes. People can get COVID-19 more than once, although it’s not common. Being vaccinated after having COVID-19 strengthens your immunity to give you better protection.

Also, people who are vaccinated have a lower risk of spreading the virus to others. This is very important because of the risks to unvaccinated people from highly contagious variants.