COVID-19 Vaccine - General Information
Below are frequently asked questions related to COVID-19 vaccine general information. Click on another category to the left to see more FAQs.
For more information on coronavirus, visit uclahealth.org/coronavirus.
There are four COVID-19 vaccines either approved or authorized for emergency use by the FDA.
- The Pfizer-BioNTech vaccine has full FDA approval for people 12 and older. Additionally, it is authorized for emergency use in children ages 5 through 11 years old and 6 months through 4 years old.
- The Moderna vaccine has full FDA approval for people 18 and older. It is authorized for emergency use in people ages 6 months to 18 years.
- The Novavax COVID-19 Vaccine, Adjuvanted was given emergency use authorization by the FDA on July 13, 2022. This authorization is specifically for unvaccinated adults who are 18 and older. The CDC also recommended this vaccine for unvaccinated adults.
- The CDC now advises that in most situations, the Pfizer-BioNTech or Moderna COVID-19 vaccines are preferred over the Johnson & Johnson vaccine for both the initial vaccine series and booster dose due to the risk of serious adverse effects.
The CDC also recommends booster doses for everyone 6 months and older, if eligible. Additional booster doses are recommended for some patients.
All four vaccines are given as an injection into the muscle. The Pfizer primary vaccine series is given in two shots, three weeks apart. The Moderna primary vaccine series is given initially in two shots, four weeks apart. The Novavax vaccine is given in two shots, three weeks apart. The Johnson & Johnson vaccine is given as a single shot. If you receive a vaccine as part of a two-dose series, you must receive the same vaccine for both doses.
The authorized vaccines still offer significant protection against SARS-CoV-2, the virus that causes COVID-19. However, there are several SARS-CoV-2 variants that scientists are actively tracking, some of which have caused increased transmissibility and increased disease severity. In some cases, antibodies developed from previous infection or vaccination are less able to neutralize these variants and prevent infection.
Pfizer and Moderna released updated (bivalent) boosters in August 2022 that target omicron subvariants, including BA.4 and BA.5, as well as the original coronavirus strain. Two studies, including one from the CDC, found that the updated bivalent COVID-19 booster also works against the latest omicron subvariants XBB and XBB.1.5. The CDC recommends one bivalent COVID-19 booster dose for everyone 5 years and older, and for children 6 months to 4 years who completed the Moderna primary series.
The ingredients for the Pfizer-BioNTech COVID-19 vaccine, the Moderna COVID-19 vaccine, the Novavax COVID-19, adjuvanted vaccine and the Johnson & Johnson/Janssen vaccine are listed on the FDA website. None of the vaccines contain the live virus that causes COVID-19, eggs, preservatives or mercury.
The Pfizer and Moderna vaccines use the same mRNA technology, but contain different ingredients to protect the mRNA, maintain the pH, and stabilize the solution. The ingredients include:
- Messenger RNA (mRNA) – the active ingredient that causes your body to produce antibodies
- Lipids – these create the fatty shell that protects the mRNA as it is stored, administered and delivered to cells
- Salts, sugar and other compounds – to maintain the proper pH balance and stabilize the vaccine
The Novavax COVID-19, adjuvanted vaccine is a protein subunit vaccine. It contains pieces (proteins) of the virus that causes COVID-19 and another ingredient called an adjuvant. These components teach your immune system how to recognize and respond quickly if infected with the actual virus spike protein. The ingredients include:
- Protein – the SARS-CoV-2 recombinant spike protein that creates an immune response to help protect your body from getting infected with COVID-19 in the future
- Lipids - cholesterol and phosphatidylcholine, which help the spike protein enter cells
- Adjuvant – helps activate the cells in the immune system
- Salts, sugars and acids – to maintain the proper pH balance and stabilize the vaccine
The Johnson & Johnson vaccine uses what’s known as “viral vector” technology. This means a harmless cold virus, adenovirus 26 (Ad26), is engineered to contain the gene for the SARS-CoV-2 “spike” protein. It also contains salts, sugar and buffers to maintain the pH and stabilize the solution. The ingredients include:
- Recombinant, replication-incompetent adenovirus type 26 expressing the SARS-CoV-2 spike protein - the active ingredient that causes your body to produce antibodies
- Salts, sugar and other compounds - to maintain the pH balance and stabilize the vaccine. Full ingredient list: Citric acid monohydrate, trisodium citrate dihydrate, ethanol, 2-hydroxypropyl-β-cyclodextrin (HBCD), polysorbate-80, sodium chloride.
The CDC now advises that in most situations, the Pfizer-BioNTech or Moderna COVID-19 vaccines are preferred over the Johnson & Johnson vaccine for both the initial vaccine series and booster dose due to the risk of serious adverse effects.
The CDC has identified a plausible causal relationship between Johnson & Johnson/Janssen COVID-19 vaccine and blood clots with low platelets (thrombosis with thrombocytopenia syndrome, or TTS). TTS is a rare but serious adverse event that happens at a rate of about 3.83 cases per million Janssen doses. It has resulted in deaths.
Learn when to consider the Johnson & Johnson vaccine.
The Johnson & Johnson vaccine uses what’s known as "viral vector" technology. This means a harmless cold virus is engineered to contain the gene for the SARS-CoV-2 "spike" protein. Once someone gets this shot, their body mounts an immune response and produces antibodies that prevent them from a future severe COVID-19 infection.
The Johnson & Johnson vaccine does not need to be transported frozen like the two currently authorized vaccines. This means it is easier to store and distribute to smaller offices and outlying areas.
If you receive the Johnson & Johnson vaccine and experience any signs of a blood clot, including severe headaches, abdominal pain, leg pain or shortness of breath, contact your doctor or seek medical care immediately.
COVID-19 has killed more than one million people in the United States. This is significantly more deaths than other viruses that we routinely vaccinate against, such as influenza, which typically causes 12,000 to 52,000 deaths in the U.S. per year, according to the CDC.
In addition to the high death toll, COVID-19 can also cause other long-term complications. The COVID-19 vaccine saves lives and decreases the likelihood of long term COVID-related problems involving the brain, heart and lungs.
COVID-19 infections, hospitalizations and death rates are disproportionately higher in lower-income communities and communities of color. Vaccines are needed to stop the virus and prevent COVID-19’s devastating health, social and financial effects on lower-income communities of color.
It depends on the setting. Now that the Pfizer and Moderna vaccines have full FDA approval, it’s easier for schools, employers, and the military to mandate COVID-19 vaccination for students and employees. Check with your employer or school for more information.
Even in settings where the COVID-19 vaccine is not mandated, it is highly encouraged that anyone eligible receive the vaccine, as it is the best way to protect yourself and those around you.