In December 2020, the Food and Drug Administration (FDA) issued emergency use authorization (EUA) for two COVID-19 vaccines, one manufactured by Pfizer-BioNTech (age 16 and up) and another by Moderna (age 18 and up). EUA is an authorization process used by the FDA if there is an emergency and enough evidence that the vaccine will be safe and helpful. Vaccines authorized for EUA still need to meet the FDA's rigorous standards for safety, effectiveness and quality. Several other vaccines are also in development.
At this time, the COVID-19 vaccines are in limited supply so it will be administered in phases. The CDC and state and local health departments have determined that those at the highest risk should get vaccinated first.
Phase one of vaccinations will focus on healthcare workers, first responders and residents of long-term care facilities. Phase two includes other essential workers, people with chronic health conditions, and people over age 65. Phase three will focus on ensuring everyone in the general public has equal access to the vaccine.
It is estimated that the general public may be able to start receiving the vaccine in the spring/summer of 2021.
Vaccines work with your immune system so your body will be ready to fight the virus if you are exposed. The COVID-19 vaccine helps your body develop proteins called antibodies that make you less susceptible to the disease.
The Pfizer-BioNtech and Moderna mRNA 1273 are mRNA vaccines. They contain the portion of mRNA that encodes the spike protein, the button on the surface of the SARS-CoV2 virus. It is not a live virus, cannot replicate itself and is quickly destroyed in the cell shortly after translation. Once the spike protein is translated by the mRNA, an immune response is elicited, resulting in production of antibodies against the spike protein. When the SARS-CoV2 spike protein is bound up by antibodies, it cannot attach to and infect human cells.
Yes, COVID-19 vaccines in the U.S. are authorized after meeting rigorous scientific standards for safety. The first authorized COVID-19 vaccine, manufactured by Pfizer-BioNTech, was studied in more than 40,000 people, to ensure they meet safety standards. The FDA will continue to monitor the safety and effectiveness of authorized vaccines through ongoing clinical trials and vaccination data.
For the most recently available vaccines, yes. Both the Pfizer-BioNTech and Moderna vaccines require two shots. The interval between shots for the Pfizer vaccine is 21 days and for the Moderna vaccine, it's 28 days.
The first shot starts building protection and the second shot strengthens the immune response. Both doses are necessary in order to ensure the vaccine’s effectiveness. The vaccines are not interchangeable, so individuals should complete the second dose with the same vaccine.
Currently, two vaccines, Pfizer-BioNTech and Moderna, are authorized and recommended to prevent COVID-19. At this point, one COVID-19 vaccine is not recommended over the other as both show similar efficacy.
One difference is in how the vaccines are stored. While both vaccines need to be kept cold, the Moderna vaccine must be stored at a temperature of a regular refrigerator freezer and can be used within 30 days after thawing, while the Pfizer vaccine requires special ultra-cold freezers and must be used with five days after thawing.
As with other vaccines, it is normal to experience some pain, redness or swelling at the injection site, fatigue, headache, muscle aches, or low-grade fever following the vaccination, which should go away on their own in a day or two. This does not mean that the vaccine has given you COVID-19. These symptoms are typical reactions to most vaccines and are a sign that your immune system is doing exactly what it is supposed to do — building up protection to the disease.
No. The vaccines contain a portion of mRNA, but not live virus. After the spike protein is produced, the mRNA is degraded. A normal immune response can lead to low grade fever or achiness, but this is not harmful. The full benefit of immunity won’t occur until a couple weeks after your second dose (booster dose). The risk of getting infected from someone who is infectious won’t diminish right away after vaccination.
According to the CDC, while rare, anaphylactic reactions have been reported following vaccination with mRNA COVID-19 vaccines. Individuals with a history of an immediate allergic reaction (of any severity) to an mRNA COVID-19 vaccine or any of its components might be at greater risk for anaphylaxis upon re-exposure to either mRNA COVID-19 vaccine.
These individuals should be evaluated by an allergist-immunologist to determine if they can safely receive the vaccine. Individuals with a history of an immediate allergic reaction of any severity to a vaccine or injectable therapy, and individuals with a history of anaphylaxis due to any cause, should be observed for 30 minutes following vaccination with mRNA COVID-19 vaccines. All other individuals should be observed for 15 minutes. Allergic reactions not related to vaccines, such as food or environmental allergies, are not a contraindication or precaution to vaccination with either mRNA COVID-19 vaccine.
Those who receive the two-dose vaccine will develop maximum immunity several weeks after the second dose. It normally takes about 2-3 weeks for cellular immunity to develop and several weeks for full antibody development.
No, you should continue to wear a mask after receiving the vaccine. The Pfizer-BioNTech and Moderna vaccines were around 95% effective in trials for preventing symptomatic and severe COVID-19. We don’t, however, know the vaccine’s effect on asymptomatic infection or transmission of the virus. It will be several months before the overall risk of exposure is low because so many others have been immunized. Until most of the population is vaccinated, wearing masks, distancing and handwashing are the only tools we have to stop the spread of COVID-19.
The best defense against COVID-19 is to continue following safety precautions. Cover your mouth and nose with a face mask when around others, avoid close contact with people who are sick, stay at least 6 feet away from people outside of your household, avoid crowds and wash your hands often and thoroughly. Get more information about steps you can take to protect yourself and others from COVID-19 here.
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