Vaccine Basics

The FDA and CDC took some important action to simplify the vaccination schedule for most individuals and ensure further protection against COVID-19.

Scroll down to find out how you can best protect yourself and your loved ones against COVID-19.

COVID-19 Vaccine Information

COVID-19 Vaccine Guidance, May 2023

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Frequently Asked Questions

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Yes, it was created quickly – but scientists have been working on this technology for 10+ years. Scientists all over the world worked together and shared information to create the COVID-19 vaccines.

The COVID-19 vaccines were tested with tens of thousands of people to make sure they meet safety standards and protect adults of different races, ethnicities, and ages. Millions of people have already safely received one of the three COVID-19 vaccines available – Pfizer, Moderna, and Johnson & Johnson. Vaccine safety is continuously monitored.

Human trials were completed for an updated bivalent booster (original plus Omicron BA.1/BA.2) earlier this summer. These trials showed improved antibody response and no safety concerns, with the same side effect profile as earlier vaccines. That version of the Omicron bivalent vaccine was then better matched to the “spike” protein of BA.4/BA.5, similar to how flu vaccines are matched each year to the circulating flu strains.

First of all, you can’t get COVID-19 from the vaccine. But after you get the vaccine, you could have some side effects. These side effects include headaches, feeling tired, or having a stomachache. The most common side effect is feeling sore or swollen where you got the shot. These side effects are normal! They are signs that your body is building protection. These side effects may be unpleasant for 1-3 days, but they are not dangerous.

If you don’t have side effects, don’t worry – your body is still building protection. Some people just react differently.

Yes. You should get the vaccine even if you have already had COVID-19. Some people have gotten COVID-19 more than once. The vaccine also offers more protection against reinfection than your body could develop on its own from already having COVID-19.

While most people who get COVID-19 recover, some develop serious health issues that can affect them for a long time. By getting the vaccine, you lessen your risk of getting sick or being hospitalized with COVID-19. You also are helping to reduce spread of COVID-19.

In April 2023, the CDC amended the guidance on the COVID-19 vaccines to simplify the schedule for most individuals. This means if you have not yet received a COVID-19 vaccine, all you need is one dose of the bivalent vaccine. For individuals who have previously received a COVID-19 vaccine, please refer to graphic above to find out if you are up-to-date.

Yes. The COVID-19 vaccine is free to everyone, regardless of insurance or immigration status. When you go to get your vaccine, you might be asked for your insurance card or your Medicaid or Medicare information. Why? The place where you are getting the vaccine might charge a small fee to your insurance company or the government. This charge cannot be passed on to you. You cannot be denied a vaccine if you do not have insurance. If you don’t have insurance, Medicare, or Medicaid, just say so. You still get the vaccine for free. For some vaccine events, you might be asked to bring proof of residency, but government-issued ID is not required.

It's being called a "bivalent booster" because it's a mix of two versions of the vaccine — both boosting protection against original coronavirus strain as well as (newly) protecting against the BA.4 and BA.5 Omicron subvariants and potentially broadening the protection against future variants. Previous doses would have only protected against the original coronavirus strain.

Due to the effectiveness of the bivalent COVID-19 vaccine, the monovalent Moderna and Pfizer vaccines are no longer recommended for use.

Yes.  Alternatives to mRNA COVID- 19 vaccines remain available for people who cannot receive an mRNA vaccine. CDC’s recommendations for use of (monovalent) Novavax or Johnson & Johnson’s Janssen COVID-19 vaccines were not affected by the updated guidance.

CDPH recommends bringing your CDC vaccination card to your appointment.

You will get a new one. CDC recommends completing a second card and stapling the two cards together and both cards should be presented when vaccination history is required for travel, employment, or other purposes.

Only for those age 5 and up. Mix-and-match is not recommended for children under 5.


 Yes, if a patient is eligible, both flu and COVID-19 vaccines can be administered at the same visit, as recommended by CDC and ACIP. In addition to flu vaccine, COVID-19 vaccine can be given with other vaccines as well, talk to your healthcare provider to learn more.

Yes. The CDC and the American College of Obstetricians and Gynecologists recommend that pregnant and recently pregnant people receive a bivalent mRNA COVID-19 vaccine booster dose following the completion of their last COVID-19 primary vaccine dose two months after their primary series dose or monovalent booster.


We understand that some people may be concerned about getting vaccinated. While these vaccines are being developed as quickly as possible, routine processes and procedures remain in place to ensure the safety of any vaccine that is authorized or approved for use. Safety is a top priority and no steps are skipped during the clinical trial process for COVID-19 vaccine. Vaccine safety checks are in-progress and will continue as long as a vaccine is available.

No steps are skipped during the clinical trial process for the COVID-19 vaccine

  • The FDA authorizes vaccines after they pass three phases of clinical trials
  • These clinical trials require thousands of people and months of data
  • The vaccine development is faster than normal because some steps are being done at the same time instead of one after another
  • When a vaccine trial is paused or cancelled, it is normal and means the safety checks are working
  • Vaccine recalls are rare. If a recall is issued, the FDA and CDC will let health officials and the media know immediately
  • After the vaccine is authorized, FDA and CDC will continue to monitor it using three federal safety systems that are already in place

Vaccine Safety Checks Are In Progress And Will Continue As Long As A Vaccine Is Available

Early Studies Have Shown The Vaccine Is Still Effective Against COVID-19 Variants

  • Evidence suggests that variants can spread more easily but there is no evidence that the new strain affects the sensitivity of diagnostic tests or that it causes more severe illness or increased risk of death
  • Data suggest current vaccines will be effective and safe in providing protection against the variant

Benefits of The COVID-19 Vaccine

  • Getting a COVID-19 vaccine has proven to protect you from severe outcomes - like hospitalization and death - due to COVID-19.
  • Getting vaccinated yourself also protects people around you, particularly people at increased risk for severe illness from COVID-19.

COVID-19 Vaccination Will Help Keep You Safe From COVID-19

COVID-19 Vaccination Is A Safer Way To Help Build Protection

  • COVID-19 can have serious, life-threatening complications, and there is no way to know how COVID-19 will affect you. And if you get sick, you could spread the disease to friends, family, and others around you.
  • Getting COVID-19 may offer some natural protection, known as immunity. But experts don’t know how long this protection lasts.
  • The risk of severe illness and death from COVID-19 far outweighs any benefits of natural immunity. COVID-19 vaccination will help protect you by creating an antibody response.
  • Together, COVID-19 vaccination and everyday preventative actions offer the best protection from COVID-19.
  • Wearing masks and social distancing help reduce your chance of being exposed to the virus or spreading it to others, but these measures are not enough. Vaccines will work with your immune system so it will be ready to fight the virus if you are exposed.

Vaccination Is An Important Tool to Help Manage The Spread of COVID-19

mRNA Vaccines: Two Vaccines Were Developed Using a New Vaccine Technology That Employs Messenger RNA (mRNA)

  • mRNA vaccines are being held to the same rigorous safety and effectiveness standards as all other types of vaccines in the United States. The only COVID-19 vaccines the Food and Drug Administration (FDA) will make available for use in the United States (by approval or emergency use authorization) are those that meet these standards.
  • mRNA vaccines cannot give someone COVID-19. They do not use the live virus that causes COVID-19.
  • mRNA vaccines do not affect or interact with our DNA in any way. mRNA never enters the nucleus of the cell, which is where our genetic material (DNA) is kept. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.

Vaccine History

Vaccinations have saved hundreds of millions of lives over the last century. Scientists have developed vaccines for Smallpox, Polio, Measles, Mumps, Rubella, Hepatitis, Meningitis and more. The WHO considers vaccine development one of the greatest global health achievements.

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