COVID-19 vaccines were tested in large clinical trials to make sure they meet safety standards. Many people were recruited to participate in these trials to see how the vaccines offer protection to people of different ages, races, and ethnicities, as well as those with different medical conditions. Though the accelerated timeline for vaccine development was unprecedented, safety remains a top priority.
The vaccines are effective
There are currently two available vaccines. All three are considered quite effective. Additional COVID-19 vaccines remain in clinical trial phases.
Moderna and Pfizer: Based on clinical trials, both the Moderna and Pfizer vaccines have been shown to be extremely effective at preventing COVID-19 infection. Pfizer is 95% effective at preventing COVID-19 and Moderna is 94.1% effective. To date, trials for both vaccines are equally effective across multiple demographics including: age, gender, race, and ethnicity.
Johnson & Johnson: The Johnson & Johnson vaccine is 66% effective and research indicates that it may be even more effective against serious illness.The vaccine also showed 86 percent efficacy against severe forms of Covid-19 in the United States. It is important to keep in mind that in any given year, the flu shot is about 40%-60% effective and prevents hundreds or thousands of deaths and serious illnesses every year. When COVID-19 vaccines were being developed researchers hoped they would be at least 50% effective.
Moderna and Pfizer require two doses. Johnson & Johnson Requires only one
Moderna and Pfizer: The first shot, or dose, helps the immune system recognize the virus. The second shot allows the body to strengthen its immune response and build its protection against the virus. After your second shot it will take your body’s immune system up to two weeks to respond to the vaccine and offer protection from the virus.
The same vaccine brand must be used for both shots. For example, if a person received the Pfizer vaccine for their first dose, they must also receive Pfizer for their second dose.
Johnson & Johnson: The Johnson & Johnson vaccine uses a different method than Moderna and Pfizer to prepare the immune response, and is able to promote robust immune response with just one dose.
At this point in time we are unsure if any of the approved vaccines will require a yearly vaccine, or booster shot.
You will not get COVID-19 from any of the approved vaccines
The vaccines created byPfizer and Moderna are mRNA vaccines and do not contain any live, weakened, or dead virus.
Very few serious problems are reported after COVID-19 vaccination
Most people do not have serious problems after receiving a vaccine. Some people might experience temporary injection site soreness, fever, chills, fatigue, headache, and muscle pain after receiving the COVID-19 vaccines.
All of these are more likely after the 2nd dose, and should go away in 24 to 48 hours. If you experience any symptoms after vaccination, you may choose to take an over-the-counter fever reducer or pain reliever.
Most side effects are normal signs that your body is building protection. Historical information and on-going research shows us that long-term side effects are typically not a concern with vaccines. Severe and serious side effects of vaccines are rare and when they do occur, it is usually within 6 weeks of receiving a vaccine. Research related to the COVID-19 vaccines will continue, and the FDA and CDC are continuing to monitor safety to ensure long-term side effects are identified, should they arise. If an issue is identified, experts will take immediate action to determine the best course of action.
A negative COVID-19 test will not be required prior to vaccination
A negative test will not be required before receiving the vaccine. Though, if you were previously positive, you must complete your period of isolation and be asymptomatic before you can receive the vaccine.
COVID-19 vaccination is appropriate for those who previously tested positive for COVID-19
If you previously tested positive for COVID-19, you may still receive the vaccine, provided you have completed your period of isolation and are asymptomatic.
Reinfection with the COVID-19 virus is possible and experts do not yet know how long someone is protected from getting sick again after recovering from COVID-19. If you are able, receiving the vaccine is the best way to protect yourself.
While there is evidence from laboratory studies that show current vaccines may be less effective against some of the newly identified strains, the immune response is incredibly complex, so the vaccine is still expected to provide some degree of protection.
These new variants, including the Delta variant, seem to spread more easily and quickly than other variants, which may lead to more cases of COVID-19. An increase in the number of cases will put more strain on healthcare resources, lead to more hospitalizations, and potentially more deaths.
So far, studies suggest that the current authorized vaccines work on the circulating variants. Scientists will continue to study these and other variants.
At this time much remains unknown. However, it is normal and expected for mutations to occur in many types of viruses. For instance, we deal with mutations in the flu every year. Experts will continue to monitor SARS-CoV-2 variants and if necessary, the vaccine development process can accommodate changes, though we are not at that point right now.
As a reminder, even after receiving the vaccine, everyone should continue to wear a mask, maintain physical distancing, engage in good hand hygiene, and stay home when not feeling well.
COVID-19 vaccinations are required for all students, faculty, and staff coming to campus this fall semester
For additional information regarding the vaccination requirement for University of Maryland students, faculty, and staff, please visit the 4Maryland website.
We are here to support you as you have questions
The decision to receive a COVID-19 vaccine is yours to make. We encourage you to talk with your primary care physician, or schedule an appointment to talk with a University Health Center provider, as you have questions about your personal health and wellbeing. You may also decide to closely review the information here and from other reputable health care organizations. As more information becomes available we will continue to provide accurate, research-based information to help you make an informed decision about protecting yourself from COVID-19.
1. Received the Johnson & Johnson vaccine at least two months ago and are age 18 or older.
2. Received a second dose of either the Pfizer-BioNTech or the Moderna vaccine at least six months ago and:
- Are age 65 or older;
- Live in a long-term-care facility;
- Are age 18 or older and have an underlying medical condition that could put them at higher risk of severe COVID-19; or
- Are age 18 or older and work or live in a location that puts them at high risk of exposure to COVID-19.
For more information about COVID-19 boosters, click here.
Vaccines are readily available across the US. However, COVID-19 prevention strategies continue to remain an important part of slowing the spread of the virus. Continue washing and sanitizing your hands, practice physical distancing, stay home if you are not feeling well, and wear a face-covering if you are not fully vaccinated.