Vaccination Frequently Asked Questions

What are the benefits of getting the vaccine?
Getting a COVID-19 vaccine can help protect you by creating an antibody response in your body without having to become sick with COVID-19. The vaccine does not give you the virus. A COVID-19 vaccine might prevent you from getting COVID-19. Or, if you get COVID-19, the vaccine might keep you from becoming seriously ill or from developing serious complications.

What COVID-19 vaccines have been approved and how do they work?
The FDA has given emergency use authorization to the Pfizer/BioNTech COVID-19 vaccine. Data has shown that the vaccine starts working soon after the first dose and has an efficacy rate of 95% seven days after the second dose. This means that about 95% of people who get the vaccine are protected from becoming seriously ill with the virus. This vaccine is approved for people age 12 and older. It requires two injections given 21 days apart.

The FDA has given emergency use authorization to the Moderna COVID-19 vaccine. Data has shown that the vaccine has an efficacy rate of 94.1%. This vaccine is approved for people age 18 and older. This vaccine requires two injections given 28 days apart.

The FDA has given emergency use authorization to the Janssen (Johnson & Johnson) vaccine. Data has shown that the vaccine has an efficacy rate of 66.3%. The FDA amended the emergency use authorization to include information about a very rare and serious type of blood clot in people who receive the vaccine. This vaccine is approved for people age 18 and older. This vaccine requires only one injection.

Coronaviruses have a spike-like structure on their surface called an S protein. COVID-19 mRNA vaccines give cells instructions for how to make a harmless piece of an S protein. After vaccination, cells begin making the protein pieces and displaying them on cell surfaces. Your immune system will recognize that the protein doesn't belong there and begin building an immune response and making antibodies.

Are the new COVID-19 vaccines safe?
Because these vaccines have such great interest, the time it took to enroll patients was extremely fast. However, the follow up was as thorough as it is for any vaccine and we now have months of data on patients who received the vaccine or placebo. This data has compared the incidence of side effects between patients who received the vaccine and placebo. Incidence of side effects other than injection site reaction is no different.

What are the possible side effects?
A COVID-19 vaccine can cause mild side effects after the first or second dose, including:

  • Pain, redness or swelling where the shot was given

  • Fever

  • Fatigue

  • Headache

  • Muscle pain

  • Chills

  • Joint pain

You'll likely be monitored for 15 minutes after getting a COVID-19 vaccine to see if you have an immediate severe reaction. Most mild side effects happen within the first three days after vaccination and typically last only one to two days.

The COVID-19 vaccine may cause side effects similar to signs and symptoms of COVID-19. If you’ve been exposed to COVID-19 and you develop symptoms more than three days after getting vaccinated, or the symptoms last more than two days, self-isolate and get tested. It is possible to contract the virus after receiving the first vaccination since antibody protection isn’t at the highest until after the 2nd dose. Wearing a mask, washing your hands and watching your distance are still recommended after being fully vaccinated.

Can I get a COVID-19 vaccine if I have a history of allergic reactions?
If you have a history of severe allergic reactions not related to vaccines or injectable medications, you may still get a COVID-19 vaccine. You should be monitored for 30 minutes after getting the vaccine.

If you’ve had an immediate allergic reaction to other vaccines or injectable medications, ask your doctor if you should get a COVID-19 vaccine. If you’ve ever had an immediate allergic reaction to any ingredient in the Pfizer or Moderna COVID-19 vaccine, the Centers for Disease Control and Prevention recommends not getting that specific vaccine. Also, people who are allergic to polysorbate should not get an mRNA COVID-19 vaccine.

If you have an immediate allergic reaction after getting the first dose of a COVID-19 vaccine, do not get the second dose.

Can pregnant or breastfeeding women get the COVID-19 vaccine?
There is no research on the safety of COVID-19 vaccines in pregnant or breastfeeding women. However, if you are pregnant or breastfeeding and part of a group recommended to get a COVID-19 vaccine, you may choose to get the vaccine. Talk to your health care provider about the risks and benefits.

Is there anyone who should not get a COVID-19 vaccine?
There is no COVID-19 vaccine yet for children under age 16.

COVID-19 vaccination might not be recommended for people with certain health conditions. Talk to your doctor if you have questions about getting the vaccine.

Should I get the COVID-19 vaccine even if I've already had COVID-19?
It's recommended that people who have already had COVID-19 get a COVID-19 vaccine. If you’ve had COVID-19, you might delay vaccination until 90 days after your diagnosis. Reinfection with the virus that causes COVID-19 is uncommon in the 90 days after you are first infected.

What should I do once I’m vaccinated?
Experts want to learn more about the protection that a COVID-19 vaccine provides and how long immunity lasts before changing safety recommendations. The Centers for Disease Control and Prevention recommends still following these precautions for avoiding infection with the COVID-19 virus:

  • Avoid close contact. This means avoiding close contact (within about 6 feet, or 2 meters) with anyone who is sick or has symptoms. Also, keep distance between yourself and others. This is especially important if you have a higher risk of serious illness.

  • Wear cloth face coverings in public places. Cloth face coverings offer extra protection in places such as the grocery store, where it's difficult to avoid close contact with others. Surgical masks may be used if available. N95 respirators should be reserved for health care providers.

  • Practice good hygiene. Wash your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitizer that contains at least 60% alcohol. Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue. Avoid touching your eyes, nose and mouth. Avoid sharing dishes, glasses, bedding and other household items if you're sick. Clean and disinfect high-touch surfaces daily.

  • Stay home if you're sick. Stay home from work, school and public areas if you're sick, unless you're going to get medical care. Avoid public transportation, taxis and ride-sharing if you're sick.

If you have a chronic medical condition and may have a higher risk of serious illness, check with your doctor about other ways to protect yourself.

This information is published courtesy of the County of San Diego, the Centers for Disease Control and Prevention (CDC) and the Mayo Clinic. Palomar Health is part of The Mayo Clinic Care Network, a collection of hospitals and health care systems that have come together with Mayo Clinic with a purpose of improving care for the patients they collectively serve. LEARN MORE

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