Safety and Effectiveness

Vaccine FAQs Index>>

How effective are the vaccines?
Updated 3/11/21

In clinical trials, all three COVID-19 vaccines authorized for use in the United States – Pfizer, Moderna and Johnson & Johnson (J&J) – are nearly 100% effective in preventing hospitalization and/or death from COVID-19. This is the benchmark public health experts are focused on, as it means they all save lives. For the Pfizer and Moderna vaccines, full protection is achieved two weeks after the second dose. For the J&J single-dose vaccine, full protection is achieved 28 days after your shot.

Will a recipient of the vaccine need to receive one or multiple doses?
Updated 03/11/21

The number of doses needed will depend on which vaccine you receive. s. For two-dose vaccines, it is critical that individuals receive BOTH doses of the same vaccine to fully benefit from the vaccine. For one-dose vaccines, individuals will only need to receive a single shot. As a reminder, all three FDA authorized COVID-19 vaccines are nearly 100% effective at preventing hospitalization and/or death from COVID-19.

Do I need to complete the vaccine series in order to achieve immuno-protection?
Updated 3/11/21

At this time, data are inadequate to indicate that the initial dose of two-dose vaccines provides protection. Immuno-protection is achieved two weeks after the second dose is administered. Both the Pfizer and Moderna vaccines are similarly effective in preventing symptomatic COVID-19 following the second dose and within the timeframe as indicated. It is not yet known whether the Pfizer and Moderna vaccines prevent asymptomatic infection, nor if people can still transmit COVID-19 after vaccination.

The Johnson & Johnson (J&J) vaccine is a single-dose vaccine. Immuno-protection is achieved 28 days after receiving your shot. While the J&J vaccine demonstrated protection against asymptomatic COVID-19 in a small number of individuals in the clinical trial, more data are needed to help us understand how the vaccines impact transmission.

Regardless of where you are in the vaccination process, it is critical to maintain good PPE and social distancing practices for the duration of the pandemic, as the vaccines have not widely demonstrated that they prevent transmission and even those with immunity could still carry and transmit the virus to those who are not vaccinated.

For two-dose vaccines, do I need to receive both doses?
Updated 03/11/21

Yes. The Pfizer and Moderna vaccines are a two-dose series and require both doses before you are considered fully vaccinated. Protection against COVID-19 is not immediate and immuno-protection is achieved two weeks after the second dose.

If I receive a two-dose vaccine, is there any benefit to shortening the interval between the first and second doses?
Updated 03/11/21

No. The appropriate interval recommended for the specific vaccine must be followed to elicit the most robust immune response. While a longer interval does not hurt, a shorter interval may be detrimental to achieving the desired level of immunity.

Can the Johnson & Johnson vaccine be used to complete my vaccination series if I received the Pfizer or Moderna vaccine for my first shot?
Updated 3/11/21

No, there are no data to support using the Janssen (Johnson & Johnson) vaccine for your second shot if you received a two-dose vaccine for your first shot. It is important that your second shot be with the same vaccine as your first shot.

Will I need the vaccine every year?
Updated 12/12/20

At this time, we do not have enough data to determine whether the COVID-19 vaccine will need to be administered annually. Vaccine manufacturers are continuing to study and monitor patients, so we expect that over time, we will learn more about whether COVID-19 vaccines will require annual shots like the flu shot.

Can someone still transmit COVID-19 after being vaccinated?
Updated 3/11/21

While transmission in vaccinated persons is still being studied, there is emerging evidence to suggest that fully vaccinated individuals are less likely to transmit COVID-19 to others. At this time, to minimize the risk of transmission to vulnerable, unvaccinated individuals, particularly those at risk for severe illness and poor outcomes, it is critical that you maintain social distancing practices and continue to use PPE in public and in the health care workplace.

If you are vaccinated and still contract COVID-19, would your symptoms be less severe?­­
Updated 3/11/21

At this time, there are no data available for individuals who have been vaccinated and are subsequently infected with COVID-19. While the Pfizer, Moderna and Johnson & Johnson vaccines are almost 100% effective at preventing hospitalization and/or death from COVID-19, additional studies are ongoing in all individuals who received the vaccine. If an individual gets COVID-19 after being vaccinated, clinical trial data suggests that severe COVID-19 may be reduced, but not all symptoms of COVID-19 would be eliminated. Over time, we expect to learn more about how COVID-19 could present in individuals who have received the vaccine, and whether the severity of symptoms is lower as a result of the vaccine.

We do not currently have enough data to determine whether the COVID-19 vaccine will need to be administered annually. Vaccine manufacturers are continuing to study and monitor patients, so we expect that over time, we will learn more about whether COVID-19 vaccines will require annual shots like the flu shot.

Will UMMS be adjusting the PPE or Infection Prevention policies and guidelines for those who have been vaccinated?
Updated 3/11/21

We are actively reviewing our PPE and other Infection Prevention policies and in the coming weeks, we will provide revised guidance based on individual and UMMS workforce COVID-19 vaccination status, as well as the current state of COVID-19 cases in our community. For the safety of our team members, patients and care partners, while in UMMS facilities, at this time team members should continue to follow UMMS infection prevention guidance, including our universal masking policy.

For two-dose vaccines, is there an exact window of time in which I have to receive the first and second doses?
Updated 03/11/21

Two-dose vaccines were studied using specific windows of time – the Pfizer vaccine doses were studied at 21 days apart, while the Moderna vaccine doses were studied at 28 days apart. It is critical that recipients do not receive the second vaccine dose prior to the 21- or 28-day timeframe following the first dose. However, it is possible to receive the second dose after the designated 21- or 28-day time frame and still reach maximum immunity. While the CDC recommends getting the second dose as close as possible to the recommended timeframe, the second dose may be given up to six weeks (42 days) after the first dose.

I have been hearing about different COVID-19 variants lately. What does this mean and how many variants have been discovered so far?
Updated 3/11/21

Viruses mutate when they replicate their RNA (or genetic makeup) in the host’s cells. A variant is simply a different version of the virus that we can identify by sequencing the virus’s genome. Sometimes, new variant strains disappear, but occasionally they can become more established than the original strain. That is what seems to be happening with a few of the new COVID-19 variants, which is why they have been getting attention in the news.

Right now, researchers are tracking three COVID-19 variants:

  • The UK variant (B.1.1.7) spreads more easily and faster than others. Currently, there is no evidence that it causes more severe illness or increased risk of death. This variant is now circulating in over 30 states and has been detected in several cases in Maryland.
  • The Brazil variant (P.1), recently detected in Minnesota, contains a set of mutations that may affect its ability to be blocked by therapeutic antibodies approved for human use.
  • The South African variant (B.1.251) shares some mutations with the UK variant. This was first identified in the U.S. in South Carolina and has recently been identified in Maryland.

Will the current COVID-19 vaccines protect against new strains of COVID-19?
Updated 3/4/21

At this time there is no evidence to suggest that these or any other strains of the COVID-19 virus are resistant to the current COVID-19 vaccines. The current vaccines provoke a powerful immune response that allows them to remain highly protective, even if there is a drop in antibody strength. Additionally, the antibodies are not the only part of the vaccines that makes them effective. There are also T cells and memory B cells and non-neutralizing antibodies that are activated by the vaccine. The FDA is formally investigating the matter and experts are still learning about these new variants, so we expect that over time we will get additional information and if necessary, future COVID-19 vaccines may need to be tweaked, not unlike what happens with the flu vaccine. mRNA vaccines like the COVID-19 vaccines can be reformulated much faster than other vaccines. Pfizer and Moderna are already developing booster vaccines, if one is needed, to ensure continued protection against these COVID-19 strains in the future.

Some of the Johnson & Johnson clinical trials were conducted in South Africa and Brazil at a time when new variant strains were emerging. The data show that the vaccine offered good protection to participants in these locations, including 100% effectiveness in preventing hospitalization and/or death.

Do I need to do anything differently to protect myself against these new strains of COVID-19?
Updated 3/11/21

Our measures and tools against COVID-19 remain the same regardless of the variant. These include getting vaccinated as soon as you are able, continuing to use masks and avoiding large gatherings. While the CDC has issued new guidelines for people who are fully vaccinated, those who are fully vaccinated must continue to take appropriate precautions when in public or when around unvaccinated people who are at increased risk of severe COVID-19.

Can I travel safely after receiving the vaccine? Can I travel without quarantining after I get the vaccine?
Updated 12/21/20

Given that we do not currently know if or to what extent the COVID-19 vaccines prevent infection or viral transmission, UMMS will not be making any adjustments to any of our Infection Prevention guidelines or policies. At this time, all UMMS employees must continue to follow all recommendations for travel restrictions and post-travel quarantine as recommended. This applies to all individuals regardless of whether you have received one or both doses of the vaccine.

Are children eligible for the COVID-19 vaccination?
Updated 3/11/21

Children will not be vaccinated until additional studies are done. The Pfizer vaccine is authorized for use in people 16 years of age and older. The Moderna and Johnson & Johnson vaccines are authorized for use in adults ages 18 and older.

Can the COVID-19 vaccine cause HIV?
Updated 12/18/20

No, the COVID-19 vaccine cannot cause HIV. A vaccine candidate being jointly developed in Australia by the University of Queensland and CSL Limited recently stopped clinical trials for their COVID-19 vaccine because it generated HIV antibodies in early-stage recipients, resulting in false-positive HIV test results. To be clear, it is scientifically impossible for this vaccine to cause HIV infection; the clinical trials in Australia were stopped because of an issue of interference with HIV diagnostic tests. This issue is not related to the Pfizer or Moderna vaccines, or any other COVID-19 vaccines in development.

The good news is, this reinforces that all COVID-19 vaccines are adhering to the same rigorous process as any other vaccine, and scientists are not skipping any procedures in developing these vaccines.

Are COVID-19 viral vector vaccines safe?
Updated 3/4/21

Yes. As with any other vaccine, viral vector vaccines for COVID-19 are rigorously tested and evaluated to confirm that they are safe. The FDA and CDC will only authorize COVID-19 vaccines for use if they meet the necessary standards. Viral vector vaccines cannot give you COVID-19.

Is it safe for immunocompromised individuals to get the Janssen (Johnson & Johnson) vaccine?
Updated 3/4/21

Yes. While immunocompromised individuals were not specifically included in the Phase 3 clinical trials, the Janssen (Johnson & Johnson) COVID-19 vaccine is considered safe for immunocompromised persons as long as there are no contraindications. As with any vaccine, these individuals should talk to their doctor prior to vaccination and continue to follow all current infection prevention guidance to protect themselves and others following vaccination.

Is it safe for people ages 60 and older with comorbidities to get the Janssen (Johnson & Johnson) vaccine?
Updated 3/4/21

Yes, the Janssen (Johnson & Johnson) vaccine is safe for people ages 60 and older who have underlying medical conditions. Data from the clinical trials show that the potential benefits of the vaccine outweigh any known and potential risks. The vaccine demonstrated similar safety in efficacy in persons with comorbidities, including those that put individuals at higher risk for severe COVID-19, compared to those who did not have comorbidities.

Vaccine FAQs Index>>

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