Child giving her teddy bear a shot

COVID-19 Vaccine Frequently Asked Questions

How do vaccines work?

Vaccines trigger the body’s natural response to fight illnesses.  Vaccines work by training the immune system to be ready to recognize viruses or bacteria when they enter the body. Then, if a person is exposed to that virus or bacteria, their immune system knows how to respond. The COVID-19 vaccines protect people from getting seriously ill and requiring hospitalization. If a vaccinated person gets COVID-19, they usually have mild symptoms.

Are COVID-19 vaccines safe?

Yes. The United States Food and Drug Administration (FDA) works to make sure that all vaccines are as safe and effective as possible through careful testing.  All vaccines must meet strict safety standards before being released to the public. Approval is only given if the vaccine is shown to be safe and the reviewers conclude that the benefits outweigh any potential risks.  Over 600 million people of different ages and races have received COVID-19 vaccines and boosters.  These vaccines are safe and are regularly monitored by the FDA and U.S. Centers for Disease Control and Prevention (CDC).

What are in the COVID-19 vaccines?

The Moderna and Pfizer vaccines have mRNA, genetic material that our cells use to make spike proteins. Then our bodies respond by making antibodies. The mRNA COVID-19 vaccines do not have preservatives, which is why they must stay frozen until they are ready to use. Novavax is a protein-based vaccine. Novavax stimulates an immune response using a technique that is well-known and established. It is similar to other common vaccines you may have had such as seasonal flu, pertussis, and hepatitis B.  Vaccines may also have lipids, salts, sugars, acids, and acid stabilizers to help keep them stable to deliver the active ingredients. Vaccines do not contain ingredients that are poisonous or harmful.  

New updated monovalent Pfizer-BioNTech and Moderna COVID-19 vaccines were approved on September 12, 2023 in the United States. These new vaccines are expected to work better against the variants spreading now. They work against the XBB lineage of the Omicron variant. 

Who can get a COVID-19 vaccine?

The CDC recommends COVID-19 vaccines for everyone aged 6 months and older.

What COVID-19 vaccines are available?

•    The FDA has given approval for the Pfizer and Moderna vaccines for people 6 months and older.
•    The FDA has given approval for the Novavax COVID-19 vaccine for people 12 years and older. Novavax offers an alternative to the mRNA vaccines for people who cannot or prefer not to get an mRNA vaccine.
•    The Johnson & Johnson (J&J/Janssen) COVID-19 vaccine is no longer avaialble in the United States.

Are the COVID-19 vaccines effective?

Yes. The vaccines produce a strong immune response in adults and young children and protect against severe disease. While certain virus variants that cause COVID-19 spread easily and may lead to breakthrough cases,  vaccines continue to protect people from becoming very sick, being hospitalized, or dying from COVID-19. Even with new variants, getting vaccinated is a safe and reliable way to protect yourself from COVID-19.  Scientists will continue to monitor these variants.

When are people considered “up-to-date” on their COVID-19 vaccines? 

Consult with a health care provider about your/your child’s vaccine status, and check the most up-to-date CDC guidance. As of September 12, 2023, the CDC recommends: 

  • Everyone aged 5 years and older get 1 dose of the updated Monovalent Pfizer-BioNTech or Moderna COVID-19 vaccine at least 2 months after their last dose 
  • Check with your health care provider for children 6 months to 4 years of age since the number of doses may be different depending on their age and type of vaccine, Pfizer-BioNTech or Moderna COVID-19 vaccine 
  • Check with your health care provider if you are a person who is moderately or severely immunocompromised. You may need additional COVID-19 vaccines. 
  • See the complete schedule at the California Department of Public Health, Immunization Branch 

COVID-19 vaccine recommendations will be updated as needed. 

How long do COVID-19 vaccines protect people?

The COVID-19 vaccines offer the best protection against getting sick with COVID-19 in the months following the shot. Two weeks after getting the vaccine, the risk of getting sick is low, and the risk gradually goes up over the first six months. However, the vaccine provides protection against severe disease, hospitalization, and death.

Are there side effects?

There can be side effects. The most common side effect is pain in the arm where people get the vaccine. Some people also have one or more of these symptoms: tiredness, headache, muscle pain, chills, joint pain, and fever. Another side effect is swollen lymph nodes in the neck or under the arm where the vaccine was given. These are all signs of the body’s immune system working.  

These side effects usually clear up within a day or two. Keep in mind, the side effects from the vaccine are generally much milder than getting COVID-19. A very small number of the many people vaccinated have had more serious side effects such as a severe allergic reaction but this is rare. Talk to your health care provider if you or your child have had a severe allergic reaction to other vaccines or ingredients. 

Should people who have already had COVID-19 get the vaccine?

Yes, you should get a COVID-19 vaccine even if you already had COVID-19.

  • People who have had COVID-19 may have some immunity, but this immunity can vary depending on how mild or severe the illness was and their age. The immunity also decreases over time.  
  • Getting the vaccine is a safer way to build immunity against COVID-19 and its variants than getting sick with the COVID-19 virus. 
  • The vaccine will help your body have a stronger response if you get COVID-19 again. 
  • People with COVID-19 should wait until they are no longer infected, and check with their health care provider before getting the vaccine. 
Do people still need to wear a mask after they've had the vaccine?

It depends on your personal risk and your community levels of COVID-19. Follow public health recommendations for wearing a mask.  This is especially important if:
•    local COVID-19 hospital admissions levels are high, or
•    your child care program is experiencing a COVID-19 outbreak, or
•    you are at risk for severe disease or are immunocompromised.
Follow CDC website guidelines for masking if you test positive, you are exposed, or you have symptoms.

Where can people get COVID-19 vaccines?

This will vary by county. You can get a vaccine from local pharmacies like CVS or Walgreens, from your health care provider, or from your public health clinic.  Your local health department or school district may also be holding vaccination clinics. Check with your local public health department or primary care provider about where the vaccine is available in your location. Parents or legal guardians need to provide signed consent for their child to receive the vaccine. Check this local website for vaccine locations and information: 

What does the vaccine cost?

Most health care plans a provide the vaccine free of charge. Individuals without coverage may use the CDC Bridge Access or the Vaccines for Children program to receive free vaccines. 

How do I talk to my child about getting the COVID-19 vaccine? 

It’s important for children to understand that the vaccine is meant to keep them healthy and safe.  

  • Be honest that the shot may hurt a bit and that the child might feel tired after they get the shot.  
  • Explain that getting the shot will protect others as well.  
  • Allow children to express their concerns and ask questions.  
  • On the day your child gets vaccinated, bring a comfort object, such as a favorite toy.  
If COVID-19 is less severe in children than adults, why should my child get vaccinated? 

Even though children experience less severe COVID-19 than adults, vaccination will protect your child in the following ways: 

  • They are less likely to get sick with COVID-19.  Not getting sick is even more important for children with underlying health conditions. 
  • They are less likely to get severe illness, be hospitalized, get multisystem inflammatory syndrome (MIS-C), or die if they get COVID-19. 
  • They are less likely to miss school because of being infected with COVID-19. 
  • They are less likely to spread COVID-19 to more vulnerable family, friends, teachers, and classmates. 
  • Your family will be able to travel more freely with less worry about getting COVID-19. 
  • It will be safer for your child to attend important educational, cultural, and social activities and family events. 
  • Getting vaccinated can help stop new variants from emerging 
Will my child be required to get the vaccine for child care entry?  

Each state's government decides which vaccines are required for school or child care entry. At this time, there is no state-wide California requirement for COVID-19 vaccination for child care entry. 

Is the vaccine required for child care workers?

Not always.  Some employers require vaccination for their workers. Getting vaccinated helps protect you and the children under your care. 

Is the vaccine recommended for pregnant people?

Yes. The COVID-19 vaccination is recommended for pregnant people. The CDC recommends that all people who are pregnant, breastfeeding, trying to get pregnant, or might become pregnant in the future be vaccinated for COVID-19.

Pregnant people are more likely to get severely ill if they get COVID-19, compared with non-pregnant people. People who contract COVID-19 while pregnant also face a higher risk of having a preterm birth. Getting a COVID-19 vaccine during pregnancy can also help protect the baby from COVID-19. Pregnant people should talk to their health care providers about getting the vaccine.

Where can I find more information?  

Contact your medical provider if you have any questions about vaccines. 

Centers for Disease Control and Prevention (2023) Stay Up to Date with Vaccines at  

Centers for Disease Control and Prevention (2023) COVID-19 Clinical Guidance at and  

California For All (2023) Vaccines at  

Updated October 2023, UCSF California Childcare Health Program

This article was made possible with funding from the Heising-Simons Foundation.