Note: Information about the COVID-19 vaccine is changing rapidly. As we learn more, we will update the following Frequently Asked Questions with new information.
Vaccines train the body’s immune system to recognize and fight viruses and bacteria. When the body is exposed again to a virus after being vaccinated against it, the body is immediately ready to fight the illness. Vaccines currently save millions of lives every year by preventing diseases like diphtheria, tetanus, pertussis, measles and influenza.
Getting a vaccine approved by the Food and Drug Administration (FDA) is a rigorous one, to ensure both safety and efficacy. The FDA must determine, based on substantial evidence and clinical data, that the vaccine is effective for immunizing people against the SARS-COV-2 virus and that its benefits outweigh its risks when used as intended. The FDA has approved the Pfizer vaccine for distribution to individuals ages 16 years and older the Moderna vaccine for individuals ages 18 and older. Read more about the FDA’s approval process.
During a public health emergency, the FDA can issue an EUA to allow the use of unapproved medical products (or unapproved uses of approved medical products) to diagnose, treat or prevent serious or life-threatening diseases. Certain safety, efficacy and other criteria must be met using the best available evidence.
A virus can spread very quickly throughout a community infecting many people. However, if enough people get vaccinated, germs cannot spread from person to person as quickly and the vast majority of people will not get sick. This is what is known as herd immunity. Herd immunity protects everyone, especially those people who cannot receive a vaccine for one reason or another, those who do not have a strong immune response to vaccines, and those with serious allergies or weakened immune systems.
The vaccine developed by Pfizer has been approved by the FDA for people ages 16 years and older, and is available for children ages 6 months to 15 under Emergency Use Authorization (EUA) by the FDA. The vaccine developed by Moderna has been approved by the FDA for people ages 18 and older, and is also available for children ages 6 months to 17 under EUA. The Johnson & Johnson vaccine has been granted EUA by the FDA for people ages 18 and older.
Although three vaccines are available in the United States at this time, more are in development.
Each vaccine will undergo the same stringent FDA review process before it receives full approval or Emergency Use Authorization (EUA). As of now, the Pfizer and Moderna vaccines have been fully approved, which means the FDA has determined, based on substantial evidence and clinical data, that both vaccines are effective for immunizing people ages 16 and older (Pfizer) and 18 and older (Moderna) against the SARS-CoV-2 virus and that its benefits outweigh its risks when used as intended. The Johnson & Johnson vaccine has received EUA for people ages 18 and older, which means the FDA has determined that, based on the best available evidence, the vaccine is safe and effective in preventing a COVID-19 infection. The Pfizer vaccine is available for children ages 6 months to 15 under a EUA and the Moderna vaccine is available for children ages 6 months to 17 years under EUA.
Notably, in Dec. 2021, the CDC issued a preferential recommendation for the use of the mRNA COVID-19 vaccines currently available in the U.S. (Pfizer and Moderna) over the Johnson & Johnson vaccine, citing rare but serious side effects.
Before any vaccine is widely distributed to the public, it is tested in clinical trials on tens of thousands of people to determine its safety and efficacy. While development and authorization of the COVID-19 vaccines were accelerated through global collaboration and the urgency to end the pandemic, this does not mean that safety corners were cut; the vaccines went through the same stringent testing process that other vaccines go through before public dissemination.
The FDA – which is globally respected for its scientific standards of vaccine safety, effectiveness and quality – has fully approved the Pfizer vaccine for use in preventing COVID-19 in people ages 16 and older and the Moderna vaccine in people ages 18 and older. This means the FDA has determined, based on substantial evidence and clinical data, that both vaccines are effective for immunizing people against the SARS-CoV-2 virus and that its benefits outweigh its risks when used as intended.
In addition, the Johnson & Johnson vaccine has undergone a stringent review process and received Emergency Use Authorization (EUA) from the FDA. This means the FDA has determined, based on the best available evidence, that the vaccine is safe and effective in preventing a COVID-19 infection. The Pfizer vaccine continues to be administered under an EUA to children ages 5 to 15.
The scientific and medical community is committed to continuing to evaluate all available evidence to improve understanding of these vaccines’ safety. After clinical data revealed a very rare but serious side effect experienced by some individuals after receiving the Johnson & Johnson vaccine, the CDC issued a preferential recommendation for the use of the mRNA COVID-19 vaccines (Pfizer and Moderna) over the Johnson & Johnson vaccine in Dec. 2021.
It is a common misconception that vaccines prevent someone from contracting the virus. Vaccines train the body’s immune system to recognize and fight viruses and bacteria. When the body is exposed to a virus after being vaccinated against it, the body is immediately ready to fight the illness. Because the body is able to respond more quickly, you are less likely to experience symptoms of the illness, especially severe and life-threatening ones. Based on clinical trials and observations following the administration of more than hundreds of millions of doses, we know the COVID-19 vaccines are extremely effective in preventing severe illness, hospitalization and death from the virus – including new strains such as the delta variant.
At this time, there is not enough data about the vaccines to know how long they will provide protection from COVID-19.
Yes. While doctors do not yet know how long you will be protected after having COVID-19, they do know it is possible to contract the virus again. Getting vaccinated protects you from suffering severe illness, hospitalization and death from COVID-19. In addition, preliminary data show that natural antibodies from a previous COVID-19 infection do not provide as much protection as the vaccines do against more contagious and aggressive strains of the virus.
No. None of the vaccines currently available use a live version of the virus, so a person who receives any of these vaccines cannot contract COVID-19 from the vaccination.
Side effects may vary depending on which vaccine you receive, but common side effects include fatigue, headache, muscle and joint pain, swollen lymph nodes and pain at the injection site, which is generally the upper arm. Before you receive your vaccine, specific information about your vaccine’s anticipated side effects will be provided to you.
Individuals 18 years of age or older are eligible to receive the Pfizer, Moderna and Johnson & Johnson COVID-19 vaccines. Children 6 months to 17 years of age are eligible to receive the Pfizer and Moderna vaccines.
Additional information about the vaccines can be found in the FDA's fact sheets for the Pfizer vaccine, Moderna vaccine and Johnson & Johnson vaccine. You may find general information about the COVID-19 vaccine on the FDA’s website.
In Dec. 2021, the CDC issued a preferential recommendation of the mRNA COVID-19 vaccines currently available in the U.S. (Pfizer and Moderna) over the Johnson & Johnson vaccine, citing rare but serious side effects. The decision was based on additional data showing 54 cases of blood clotting, more specifically a condition known as thrombosis with thrombocytopenia syndrome, or TTS, after the Johnson & Johnson vaccine. This condition has also been documented after the AstraZeneca vaccine (not authorized in the U.S.), which, like Johnson & Johnson, uses a genetically modified cold virus (instead of mRNA) to carry instructions for making the spike protein mimicking the one on the SARS-CoV-2 virus.
Of those 54 cases, 9 people died. Notably, more than 14 million doses of the Johnson & Johnson vaccine have been given in the U.S. as of Aug. 31, 2021, so this remains a very rare side effect, occurring at a reported rate of 3.83 per 1 million doses (with the death rate of .57 per 1 million doses). Rates of TTS were highest among females ages 30 to 39. (Data from December 2021)
While the chance of developing blood clots, Guillain-Barre Syndrome or any other adverse reaction from the Johnson & Johnson COVID-19 vaccine is extremely rare, individuals should contact their health care provider if they develop serious symptoms in the days and weeks after being vaccinated. Symptoms of blood clots may include headache, blurred vision, fainting or loss of consciousness, loss of control over movement in part of the body, abdominal pain, shortness of breath, leg pain/swelling and seizures. Symptoms of Guillain-Barre Syndrome may include varying degrees of weakness or tingling sensations starting in the legs and hands, loss of reflexes and an inability to walk, climb stairs or maintain steadiness when walking.
While the chance of developing blood clots, Guillain-Barre Syndrome or any other adverse reaction from the Johnson & Johnson COVID-19 vaccine is extremely rare, individuals should contact their health care provider if they develop serious symptoms in the days and weeks after being vaccinated. Symptoms of blood clots may include headache, blurred vision, fainting or loss of consciousness, loss of control over movement in part of the body, abdominal pain, shortness of breath, leg pain/swelling and seizures. Symptoms of Guillain-Barre Syndrome may include varying degrees of weakness or tingling sensations starting in the legs and hands, loss of reflexes and an inability to walk, climb stairs or maintain steadiness when walking.
Yes. The preferential recommendation still allows individuals to receive the Johnson & Johnson vaccine, including if they are unable to or uncomfortable getting an mRNA vaccine. Following this guidance from the CDC, Memorial Hermann recommends the Pfizer and Moderna COVID-19 vaccines over the Johnson & Johnson vaccine for those who meet vaccine eligibility. Moving forward, we will follow the below guidelines from the CDC:
No. The COVID-19 vaccines do not affect DNA. The vaccines train the body’s immune system to recognize and fight the virus.
No. You do not have to show proof of residency to get a COVID-19 vaccine, and you do not need a Social Security number.
Yes. To ensure we have accurate information for your vaccine record, we will ask for your photo ID. Any of the following forms of identification will be acceptable as photo ID:
Yes. The Centers for Disease Control and Prevention (CDC) has recommended that pregnant women get a COVID-19 vaccine after research showed that the vaccine does not pose additional risks for mothers or babies. In addition, the CDC has stated the vaccines pose no risk for breastfeeding women or their babies. In fact, studies have shown that the COVID-19 vaccine provides protection to infants through breast milk.
If you are pregnant or breastfeeding, we encourage you to have a conversation with your health care provider to help you decide. In addition, according to the CDC, the mRNA vaccines currently available in the U.S. (Pfizer and Moderna) are recommended over the Johnson & Johnson vaccine, citing rare but serious side effects.
You do not need to take action to make sure your vaccination is registered. Memorial Hermann will report all vaccinations to ImmTrac2, the statewide immunization registry. That record will contain the details of your vaccination – the brand of vaccine you received, for instance, and when you receive the second dose – and it can be accessed later by medical professionals.
The U.S. Food and Drug Administration (FDA), which is globally respected for its scientific standards of vaccine safety, effectiveness and quality, most recently authorized the emergency use of two COVID-19 vaccines in children ages 6 months and older. The Pfizer-BioNTech COVID-19 vaccine has been authorized for the prevention of COVID-19 in children ages 6 months to 4 years old, and the Moderna COVID-19 vaccine has been authorized for the prevention of COVID-19 in children ages 6 months to 5 years old. The FDA evaluated data from approximately 2,970 pediatric study participants for the Pfizer-BioNTech vaccine and approximately 4,700 for the Moderna COVID-19 vaccine to ensure that each vaccine is safe for this age group. Additionally, both vaccines have been authorized for children through age 17. Based on this research, the American Academy of Pediatrics recommends that all eligible children receive the COVID-19 vaccine as soon as possible.
Keep in mind, low risk is not no risk. While most children with COVID-19 have mild symptoms or have no symptoms at all, severe illness and death have been reported in children under the age of 1 as well as in children with underlying health conditions. Vaccines are helpful in preventing illness and disease, and the COVID-19 vaccine is no different. Getting vaccinated protects children from developing severe complications from COVID-19 and may reduce the chance they could spread the infection to other more vulnerable family members and friends. The effectiveness of the vaccines for children ages 6 months to 4 years–which have most recently received emergency use authorization–has been found to be similar to that in the older age groups.
While doctors do not know yet how long we are protected after having COVID-19, they do know it is possible to contract the virus again—and early research is showing that natural immunity may not be as effective as vaccines in protecting against new strains of the virus. The CDC recommends vaccination even for those who were previously infected, especially as more infectious COVID-19 variants develop.
Although less likely, it is possible for vaccinated individuals to contract COVID-19 and spread it to others. This combined with more transmissible COVID-19 variants—which account for the majority of current cases in the U.S.—puts children at risk of getting sick with the virus and spreading it to others, particularly while in close contact with other children.
As with other vaccines, children may feel tired or have a sore arm, low-grade fever and other flu-like symptoms following COVID-19 vaccination. However, these symptoms are typically mild and go away within 48 hours.
According to the Centers for Disease Control and Prevention (CDC), there is no evidence that any vaccine, including the COVID-19 vaccine, impacts development or fertility.
Yes. Children with food allergies can safely get the COVID-19 vaccine. Unlike the flu shot, the COVID-19 vaccine does not contain food products such as egg proteins. If your child is allergic to polyethylene glycol (PEG), or has experienced a severe allergic reaction to other injectable treatments, please consult with a doctor.
Federal health officials—including those with the American Academy of Pediatrics—have advised that heart inflammation (myocarditis and pericarditis) is an extremely rare side effect of the COVID-19 vaccine. Importantly, for the young people who do experience this side effect, most cases are mild and individuals recover often on their own or with minimal treatment. Myocarditis and pericarditis are much more common in individuals who contract COVID-19, and the risks to the heart from COVID-19 infection can be more severe.
Yes, according to the CDC, the COVID-19 vaccine may be given simultaneously with other vaccines. Extensive experience with non-COVID-19 vaccines has shown that the ability of a vaccine to create an immune response and potential side effects are generally similar when vaccines are administered simultaneously as when they are administered alone.
The FDA has authorized a three-dose series of the Pfizer-BioNTech COVID-19 vaccine for children 6 months to 4 years of age. The first two doses should be administered 21 days apart with a third dose administered at least 8 weeks after the second dose. The FDA has also authorized a two-dose series of the Moderna COVID-19 vaccine for children 6 months to 5 years of age, with the first and second doses given one month apart. For children ages 5 years and older, the FDA has authorized a two-dose series of the Pfizer-BioNTech COVID-19 vaccine, and each dose should be administered 21 days apart. In addition, the FDA has authorized a two-dose series of the Moderna vaccine for children 6 years and older, administered 28 days apart. Eligible children are encouraged to get their first dose as soon as possible.
Memorial Hermann is pleased to offer free COVID-19 vaccinations. The COVID-19 vaccine is being offered by appointment only to new and established patients ages 6 months and older at a number of Children’s Memorial Hermann Pediatrics locations and Memorial Hermann-affiliated pediatrician practices. Parents should call their pediatrician’s office to schedule a COVID-19 vaccination appointment. Please note, minors (individuals 6 months through 17 years of age) will be required to have an adult accompany them to their vaccination appointment.
In line with guidance from the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC), Memorial Hermann is offering COVID-19 vaccine booster shots to all eligible members of our community ages 5 and older.
Please pay careful attention to the eligibility guidelines below:
Individuals should speak with their physician to determine whether a booster shot or additional/third dose of the COVID-19 vaccine is recommended for them and, if so, which one.
According to the CDC, individuals with moderately to severely compromised immune systems include those who have:
According to the CDC, individuals 18 and older may choose the type of vaccine they receive as a booster, and it does not matter which vaccine they received for their initial series. Some may have a preference for the vaccine type that they originally received and others may prefer to get a different booster. In most situations, the Pfizer or Moderna mRNA COVID-19 vaccines are preferred over the Johnson & Johnson COVID-19 vaccine for primary and booster vaccination. Individuals ages 12 to 17 who received a Pfizer COVID-19 vaccine may receive only a Pfizer booster shot at this time.
The COVID-19 vaccine is widely accessible across the Greater Houston area. Eligible members of the community are encouraged to visit their local retail pharmacy or primary care physician for COVID-19 vaccination.
Yes. Individuals who qualify for a booster shot or additional/third dose may receive their vaccination at Memorial Hermann regardless of where they received their initial vaccine series.
Please have a photo ID with you, as well as your COVID-19 vaccination card to verify the appropriate timing of your vaccination. No additional documentation is required.
Please note that minors will be required to have an adult accompany them to receive their vaccination. Minors do not have to show ID to receive the vaccine, but their parents/legal representatives do.
While not currently available for children ages 6 months through 4 years old, the FDA and CDC has granted approval for children ages 5 and older to receive a booster dose of Pfizer/BioNTech's COVID-19 vaccine. The booster shot is available for kids who received their second dose of the COVID-19 vaccine at least five months ago.
Still have questions about the COVID-19 vaccine? Fill out the form below to contact a representative from our Nurse Health Line.