A man receives a COVID-19 vaccine in his upper arm

COVID-19 Vaccines


COVID-19 vaccines are now being administered to people throughout the United States. Public health officials hope much of the nation will be inoculated this year to stop the coronavirus spread. Here are answers to some frequently asked questions.

  • What vaccines are available?
  • Multiple vaccines have been authorized for use in the United States. The first was developed by the pharmaceutical firms Pfizer and BioNTech, and it consists of two shots, given three weeks apart. The second available vaccine, Moderna, was developed by a Massachusetts biotechnology company in partnership with the National Institute of Allergy and Infectious Diseases. It consists of two shots, given 28 days apart.

    U.S. regulators have approved a third vaccine, this one made by Janssen Pharmaceuticals Companies of Johnson & Johnson. It requires only a single shot and is easy to use, ship and store. Like the Pfizer and Moderna vaccines, it was proven safe and effective in extensive clinical trials. The nation’s leading medical experts urge people to take whichever coronavirus vaccine is available to them.

  • How do they work?
  • The Pfizer and Moderna vaccines employ messenger RNA technology, which has been approved by the Food and Drug Administration (FDA) for human use. The vaccines contain molecular instructions that prompt your cells to create a protein in response to a protein on the surface of the coronavirus. In that way, the vaccines prepare your immune system to ward off the virus if it should try to invade your healthy cells.

    The Johnson & Johnson vaccine works differently. It uses a harmless cold virus to deliver a gene that helps your body’s immune system recognize and respond to the coronavirus.

  • The vaccines were developed very quickly. Are they safe?
  • COVID-19 vaccines were developed in record time for explainable reasons. Modern scientific tools are much faster than older technology, and scientists around the world worked together to develop a vaccine to fight the global pandemic. The vaccines were tested in large, randomized clinical trials with tens of thousands of people of different ages, races and ethnicities, some with various medical conditions, which allowed researchers to quickly gather data and answer key questions about safety and protection. 

    All of the vaccines passed rigorous safety reviews by the FDA. The benefits of the vaccines were determined to far outweigh the harms associated with acquiring a COVID-19 infection. The Centers for Disease Control and Prevention (CDC) have several systems in place to ensure safety and to continue to collect information on people’s experiences with the vaccine.
  • Will I suffer side effects?
  • Most people do not have serious problems after being vaccinated. Your arm may be sore, red or warm to the touch where the shot was given. Some people report flu-like symptoms, such as fever, chills and headaches, especially after the second vaccine. These side effects are normal signs that your immune system is building up protection from the disease. If symptoms increase after 24-48 hours, contact your healthcare provider.
  •  Do some people have allergic reactions to the shot?
  • Allergic reactions to vaccinations can occur. The most serious reaction is anaphylactic, which is severe and very rare. Possible symptoms of anaphylaxis include a skin rash, nausea, vomiting, difficulty breathing and shock, generally within minutes of receiving the vaccine. Anaphylaxis can be quickly reversed with an intramuscular injection, such as epinephrine. People who have had previous severe allergic reactions to other types of vaccines should talk to a medical professional before getting the COVID-19 vaccine.
  •  Will I still need to wear a mask and avoid close contact with others after I am fully vaccinated?
  • No, fully vaccinated people can resume activities without wearing a mask or physically distancing, except where required by federal, state, local, tribal, or territorial laws, rules, and regulations, including local business and workplace guidance. Fully vaccinated means it has been two weeks since your second Pfizer or Moderna shot or two weeks after receiving the single Johnson & Johnson shot.
  •  How much will the vaccine cost?
  • The federal government is providing the vaccine at no charge to people living in the United States. However, your vaccination provider may bill your insurance company, Medicaid, or Medicare for an administration fee.
  • Who has access to the data provided when people get vaccinated? 
  • The California Department of Public Health is responsible for monitoring vaccine use, and they have a data-use agreement with the CDC. According to the agreement, California will not share information that would allow the federal government to identify an individual based on the information they are given. Information provided will include a person’s birth year, sex, and county where the vaccine was administered. Vaccine eligibility is not based on residency or immigration status.
  • Can employers ask about workers’ vaccination status or require workers to be vaccinated?
  • Yes, employers can ask workers for their vaccination status. It is not a violation of HIPPA or privacy laws. Employers can also require all workers to be vaccinated, so long as they comply with ADA & Title VII. They cannot discriminate against people who cannot be vaccinated due to religious beliefs or medical conditions. (source)
  • Do employers need to track which employees are vaccinated and which are not?
  • If an employer changes their workplace safety procedures based on vaccination status or requires workers to be vaccinated, vaccination status must be documented. The employer must record the vaccination status for any employee not wearing a face covering indoors and this record must be kept confidential.

    Acceptable options include any one of the following:

    - Employees provide proof of vaccination (vaccine card, image of vaccine card or health care document showing vaccination status) and employer maintains a copy.
    - Employees provide proof of vaccination. The employer maintains a record of the employees who presented proof, but not the vaccine record itself.
    - Employees self-attest to vaccination status and employer maintains a record of who self-attests.

    Nothing in the revised ETS prevents an employer from requiring all employees to wear a face covering instead of having a documentation process. (source)

  • Who can receive vaccine boosters?
  • As of 9/24/2021, CDPH recommends that certain individuals who received both shots of the Pfizer-BioNTech COVID-19 vaccine should receive the Pfizer-BioNTech COVID-19 booster vaccine six months or later after their second shot.
    People who should receive a booster include:
    - Age 65 years and older
    - Long-term care residents
    - Age 50 through 64 years with underlying medical conditions or at increased risk of social inequities (including communities of color and others at risk of inequities)

    People who may consider receiving a booster include:
    - Age 18 through 49 years with underlying medical conditions
    - Age 18 through 64 who are at increased risk of exposure to COVID-19 due to their occupation (e.g. healthcare workers, teachers, food and agriculture workers, and others)

    Note: As of 10/1/2021, boosters for those who received the Moderna or Johnson & Johnson vaccines are not yet recommended, but under development.

More COVID-19 vaccine information in multiple languages is available from the Centers for Disease Control and Prevention.