After extensive testing, three COVID-19 vaccinations have been approved by the FDA for public use:

• Moderna, Johnson & Johnson, and Pfizer/BioNTech.
• Moderna, Johnson & Johnson, and Pfizer are U.S. companies.

• Two new vaccines–AstraZeneca/Oxford and Novavax–are expected to be available by the spring if they successfully complete their testing and safety reviews.

• All Americans will have the option to get vaccinated by May 2021

Getting immunized against COVID-19 will keep most people from getting sick. Even in a rare case where one does catch the virus, the vaccine will likely prevent you from becoming seriously ill. Protecting yourself also protects the people around you, like those at increased risk of severe illness from COVID-19 or those who can’t get vaccinated — like infants, or people with weakened immune systems from things like chemotherapy for cancer. We are still learning how the vaccine affects whether people can still transmit COVID-19 to others. It may be possible that a vaccinated person can still carry the virus and infect others, even if that person does not appear to be sick. That’s why, until enough Americans are vaccinated to fight off COVID-19, we will need to keep wearing masks, stay 6 feet apart from people we don’t live with, avoid crowds, and wash our hands frequently.

Based on decades of understanding immune response and how vaccines work. Thousands of volunteers participated in clinical trials that started that spring, making sure we can trust the vaccines to be safe and effective. Based on the results, the U.S. Food and Drug Administration (FDA) has authorized multiple vaccines for public use in December 2020 and a third in February 2021. The vaccines met the agency’s rigorous and science-based standards for quality, safety, and effectiveness. COVID-19 is a new virus requiring new vaccines, but vaccines have been saving lives and protecting us for centuries. Now, medical experts believe COVID-19 vaccines can help us move forward in our everyday lives.

Every vaccine must go through rigorous testing and inspection to ensure it is safe. Vaccines for COVID-19 followed a 3-phase process where there are several stages before FDA authorization: Phase 1: The vaccine is tested in a small number of generally healthy adults, usually between 20 and 80 people. It’s evaluated for safety, dosage, and any side effects. Experts also look at what type of immune response is created. Phase 2: If there are no safety concerns from Phase I studies, the vaccine is given in various dosages to hundreds of adults who may have a variety of health issues and come from different backgrounds to make sure it is safe. These studies provide additional safety information on common short-term side effects and risks, examine the relationship between the dose given and the immune response, and may provide initial information regarding the effectiveness of the vaccine. Phase 3: Experts broaden the study to include thousands of adults, from a variety of ages and backgrounds. They see how many people who got the vaccine were protected from the disease, compared to those who received a placebo.

Researchers made sure that the trials included adults of diverse backgrounds, races, ethnicities, and geographic areas. They collaborated with faith leaders, community organizations, and health clinics to reach volunteers from many different walks of life across the United States. Medical experts and doctors want to make sure the vaccines work safely and effectively for as many people as possible. People may respond differently to vaccines based on factors like age, gender, and health conditions — so it is important to have a diverse group of participants in clinical trials. COVID-19 has hit hard in the Black and Hispanic communities. Historically, these populations haven’t always been included in clinical research, but with COVID-19 vaccines researchers made sure volunteers included people of color, as well as people over the age of 65 who are at higher risk of complications from the virus.

Pregnant women who get infected with COVID-19 disease are more likely to have severe disease. Pregnant women are recommended to receive COVID-19 vaccine, but you should consult with your primary care physician to ensure it’s the right choice for you.

Immunization against COVID-19 will help protect you for the near future, but it’s still not clear how long the protection will last. We will have a clearer picture of how long immunity lasts in years to come when we have collected more data. Both natural immunity and immunity from the vaccine are important ways to fight COVID-19 that experts are trying to learn more about, and places like the CDC will keep the public informed as new evidence becomes available.

It’s normal to experience some mild discomfort following a vaccine. This means it’s working and creating an immune response in your body. You may feel soreness or experience some swelling in your arm. You may also feel tired, have a headache, fever, or chills.

These symptoms do not mean you have COVID-19 — it’s not possible to get COVID-19 from the vaccine. These symptoms may impact your daily activities, but they shouldn’t last more than 2-3 days. If they continue or get worse, call your doctor, nurse, or clinic. Even if you have these types of effects after your first shot, it’s important to make sure you get the second one, unless a vaccination provider or your doctor tells you not to get a second shot. Ask your doctor if you have questions.

Your body takes time to build immunity. You may not be fully protected against COVID-19 until 1-2 weeks after your second shot. In most cases, discomfort from fever or pain is normal. Contact your doctor or healthcare provider:

• If the redness or tenderness where you got the shot increases after 24 hours
• If your symptoms are worrying you or do not seem to be going away after a few days
• If you get a COVID-19 vaccine and you think you might be having a severe allergic reaction after leaving the vaccination site, seek immediate medical care by calling 911. Learn more about COVID-19 vaccines and rare severe allergic reactions.

The CDC and FDA have recommended the use of Johnson & Johnson’s Janssen (J&J/Janssen) COVID-19 Vaccine resume in the United States, effective April 23, 2021. The FDA has determined that the available data show that the vaccine’s known and potential benefits outweigh its known and potential risks in individuals 18 years of age and older.

Mild to moderate headaches and muscle aches are common in the first three days after vaccination and don’t require emergency care.

If you received the Janssen/Johnson & Johnson vaccine within the last three weeks and are experiencing any unexplained new severe symptoms, seek emergency care. Possible symptoms include:

• Shortness of breath
• Stomach pain
• Severe headache
• New neurological symptoms
• Leg pain or swelling
• Severe backache
• Unexpected bruising
• Tiny red spots on the skin

Women younger than 50 years old especially should be aware of the rare risk of blood clots with low platelets after vaccination, and that other COVID-19 vaccines are available where this risk has not been seen.

If you have an underlying medical condition, you can receive the FDA-authorized COVID-19 vaccines. In fact, vaccination is especially important for adults of any age with certain underlying medical conditions, like diabetes and high blood pressure, because they are at increased risk for severe illness from COVID-19. Ask your doctor if you have specific questions.

If you have an autoimmune condition, you may receive an mRNA COVID-19 vaccine (Pfizer or Moderna). However, you should consult with your doctor, nurse, or other health providers to discuss whether to get a COVID-19 vaccine.

When we get a vaccine, it activates our immune response. This helps our bodies learn to fight off the virus without the danger of an actual infection. If we are exposed to the virus in the future, our immune system “remembers” how to fight it. Some COVID-19 vaccines use messenger RNA, or mRNA. mRNA vaccines do not contain a live virus — they give our bodies “instructions” for how to make and fight the harmless spike-shaped proteins that will protect against a COVID-19 infection. While these vaccines use new technology, researchers have been studying them for decades.

Medical experts do not know exactly what percentage of people would need to get vaccinated to achieve herd immunity to COVID-19. Herd immunity is a term used to describe when enough people have protection — either from previous infection or vaccination — that it is unlikely a virus or bacteria can spread and cause disease. As a result, everyone within the community is protected even if some people don’t have any protection themselves. The percentage of people who need to have protection in order to achieve herd immunity varies by disease.

Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune.

There are two main paths to herd immunity for COVID-19 — infection, and vaccines.

Unlike natural infection, when people pass a virus on to one another, vaccines create immunity without causing illness or resulting complications. Using the concept of herd immunity, vaccines have successfully controlled contagious diseases such as smallpox, polio, diphtheria, rubella, and many others.

Many teams of medical experts around the world have helped in the search for a safe and effective COVID-19 vaccine — including many of the leading doctors here in the United States. Having multiple vaccines in development and production is crucial so that vaccination programs can be rolled out in many different countries at the same time, reaching as many people as possible. Hundreds of millions of vaccine doses have already been distributed and hundreds of millions more are in production. New vaccine candidates are also in development which may provide more options, as well as additional quantities for the American people.

State and local governments will ultimately decide when each group gets access to vaccines based on the local supply. That way, communities can set the priorities that work for them. The federal government does not mandate vaccines or set the rules for each community. As more vaccines are produced over the first half of 2021, more people will be able to get vaccinated based on recommendations from the Advisory Committee on Immunization Practices (ACIP) and the CDC. If you have questions, make sure you talk to your doctor. Some people — like pregnant women or people with certain severe allergies — might be told to wait to get a specific vaccine once it’s available. Your doctor should be able to tell you when and where you can get your shots. It might be at a hospital, the doctor’s office, a pharmacy, or a drive-thru clinic.

If you’ve had COVID-19 in the past 90 days, talk to your doctor about when you should get vaccinated. People who have already had COVID-19 should still eventually get vaccinated to ensure they are protected. Over the next few months, with more and more people getting vaccinated, we will find out more about how the vaccines protect people who have already had COVID-19. COVID-19 vaccination should be offered to you regardless of whether you already had COVID-19 infection. You should not be required to have an antibody test before you are vaccinated. However, anyone currently infected with COVID-19 should wait to get vaccinated until after their illness has resolved and after they have met the criteria to discontinue isolation.

New variants of the virus that causes COVID-19 illness have emerged. Current data suggest that COVID-19 vaccines used in the United States should work against these variants. For this reason, COVID-19 vaccines are an essential tool to protect people against COVID-19, including against new variants. CDC recommends getting vaccinated as soon as a vaccine is available to you.

According to the latest CDC guidance, fully vaccinated Americans do not need to wear a mask indoors or outdoors in most situations.

The agency was not specific about masking in some settings, including schools. And even fully vaccinated people are still told to cover their faces when visiting health care facilities, while flying or taking public transit, and in congregate settings such as homeless shelters, as well as prisons or jails.

Continuing to wear a mask helps protect others while we learn more about how COVID-19 spreads. It also helps protect people who are not able to get vaccinated — such as pregnant women or young children.

We need to work together to get to the end of this pandemic. While trial data suggests authorized COVID-19 vaccines are highly effective, we will only manage the pandemic if enough people take them. Vaccine manufacturers are producing and distributing millions of doses of the vaccines and all 50 states have announced when they plan to open up coronavirus vaccinations to everyone eligible under US Food and Drug Administration emergency use authorizations — if they haven’t done so already. Until enough people have been immunized against COVID-19, we should continue wearing masks, staying 6 feet apart from people we don’t live with, avoiding crowds, and washing our hands.