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COVID-19 Vaccines

Updated 10/13/21

What COVID-19 vaccines are available?

The FDA has authorized several COVID-19 vaccines for emergency use and does not recommend one type over another. As of October 1, 2021 more than 214 million Americans, or about 65% of the total U.S. population has received at least one dose. About 184 million people or 55% are fully vaccinated. 83% of people over the age 65 are fully vaccinated. The vaccines available include messenger RNA (mRNA) and viral vector/adenovirus vaccines, both of which use newe technology. Another more traditional protein subunit vaccine may be available soon.

What are messenger RNA (mRNA) vaccines?

Messenger RNA (mRNA) vaccines are available in the United States from Pfizer-BioNTech and Moderna. These vaccines use new technology for the development of mRNA that has been engineered in a lab. Tiny pieces of genetic code are delivered to body cells by a small enclosure made of fat. After the vaccination, when the mRNA delivery enters a cell, it provides the body with instructions for making the spike (S) protein found in the COVID-19 virus. The S protein stimulates the body to react with an immune response, fighting the actual virus if the body becomes infected. Cases of myocarditis and pericarditis in adolescents and young adults have been reported more often after getting the second doses of Pfizer-BioNTech or Moderna. Although they had generally high rates of effectiveness in initial studies, the efficacies have fluctuated in continuing research over time. The CDC recently recommended that some people who received mRNA vaccines get a booster shot against virus variants, such as Delta, that have emerged. The Pfizer-BioNTech but not the Moderna booster has been authorized by the FDA. See more information about boosters below. Visit the CDC website for more information about mRNA vaccines.

What are viral vector / adenovirus vaccines?

Another vaccine, available from Janssen/Johnson & Johnson, is based on new viral vector or adenovirus technology. This vaccine extracts genetic DNA material from the COVID-19 virus and uses a viral vector (an unrelated common virus that doesn’t replicate) as a shell to deliver it into body cells. After the vaccination, when the viral vector enters a cell, it provides instructions for making the spike (S) protein found in the COVID-19 virus. The S protein stimulates the body to react, creating defensive white blood cells and antibodies, which will fight the virus if the body becomes infected. While studies showed it had a 72% overall rate of effectiveness against the original virus, continuing research is still limited. The CDC recently recommended that some people who received the viral vector vaccine get a booster shot against virus variants, such as Delta, that have emerged, however, the booster has not yet been authorized by the FDA. See more information about boosters below. Visit the CDC website for more information about viral vector vaccines.

What are protein subunit vaccines?

A third type of vaccine, called a protein subunit vaccine is based on traditional science similar to the how protein-based flu vaccines are made. It uses a tiny piece of the coronavirus, the spike (S) protein, which has undergone a purification process. The vaccine includes a nanoparticle dose of the protein, along with a natural soapbark tree extraction that encourages immune cells to activate. Unlike mRNA or viral vector vaccines, the body isn’t required to make a protein since the protein is already in the dose. After the vaccination, when the body’s immune system recognizes an invading S protein, it creates a potent immune response, which will fight the virus if infected. The pharmaceutical company Novavax has developed this type of vaccine and in clinical trials, it had an over 90% rate of efficacy against the original virus and several variants. On October 1, 2021, it announced that it is applying for an Emergency Use Authorization with the FDA. Visit the NIH website for more information about protein subunit vaccines. Click here for Novavax clinical trial information.

Do I need to get a booster shot if I've been vaccinated?

Currently, the only booster shot that has been authorized by the FDA are for certain people who received the Pfizer-BioNTech vaccine. According to the CDC, people who received the Moderna or Janssen/Johnson & Johnson vaccine will need boosters but the FDA has not yet authorized them until more data on their effectiveness and safety is available. The booster must be from the same company that provided the original vaccine.

A small clinical trial showed that the Pfizer-BioNTech booster shot increased the immune response in trial participants. According to the CDC, it should improve protection against COVID-19 and the Delta variant. The following people are eligible to receive a booster if they completed their initial Pfizer-BioNTech vaccine series at least 6 months ago:

  • 65 years and older
  • Age 18+ who live in long-term care settings
  • Age 18+ who have underlying medical conditions. See Medical Conditions belwo for more information.
  • Age 18+ who work in high-risk settings. This currently includes people who work in the following professions:
    • Healthcare, firefighters, police, congregate care
    • Education
    • Food and agriculture
    • Manufacturing
    • Corrections
    • U.S. Postal Service
    • Public transit
    • Grocery stores
  • Age 18+ who live in high risk settings (e.g. group homes, schools, correctional facilities, homeless shelters)

Visit the CDC website for more information about the booster shot.

What is a breakthrough infection after being vaccinated?

According to the CDC, breakthrough infections happen in a small percentage of people who are fully vaccinated. Fully vaccinated people can become infected with variants, be infectious, and spread the virus to others. The CDC has updated their recommendations for fully vaccinated to:

  • Wear a mask in public indoor settings in areas of substantial or high transmission.
  • Choose to wear a mask regardless of level of transmission particularly if individual are at risk or have someone in their household at increased risk.

Get tested 3-5 days following a known exposure to someone with suspected or confirmed COVID-19 and wear a mask in public indoor settings for 14 days after exposure or until a negative test result.

Where do I get a vaccination or booster?

Residents may receive communication from their health care provider with information on how to receive the vaccine. To find locations that are administering free vaccines and for additional information, visit the Los Angeles County Vaccination page.

Where can I get up-to-date information?

The information on this page has been obtained from the Centers for Disease Control (CDC), the National Institutes of Health (NIAID), and the Los Angeles County Department of Public Health. You may check back here as we periodically update this information.

Our Resources page also has links to the Centers for Disease Control (CDC), Los Angeles County Department of Public Health, City of Los Angeles, and World Health Organization for up-to-date information locally, nationally and worldwide.

The information on this page is provided for general, informational purposes and not personalized medical advice. Please contact your health care provider for medical advice specific to your situation and/or regarding getting the vaccine or booster. If you are having a medical emergency please call 911.

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