Vaccines FAQ

Being vaccinated against COVID-19 helps the body develop a memory response to fight off the virus that causes COVID-19, without having to get the illness. COVID-19 vaccines also decrease the likelihood of severe illness or death if infection does occur. For more information, see Understanding How COVID-19 Vaccines Work (CDC).

The vaccines manufactured by Pfizer and Moderna are mRNA vaccines. mRNA vaccines contain material from SARS-CoV-2, the virus that causes COVID-19, which gives our cells instructions for how to make a harmless protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes (white blood cells) that will remember how to fight the virus that causes COVID-19 if we are infected in the future.

mRNA vaccines do not contain a live virus and do not carry a risk of causing disease in the vaccinated person. mRNA from the vaccine never enters the nucleus of the cell and does not affect or interact with a person’s DNA. For more information on mRNA vaccines, see Understanding and Explaining mRNA COVID-19 Vaccines (CDC).

The COVID-19 vaccine manufactured by Janssen (Johnson & Johnson) is a viral vector vaccine. Viral vector vaccines use a modified version of a different virus (the vector) to deliver important instructions to our cells. For COVID-19 viral vector vaccines, the vector (not the virus that causes COVID-19, but a different, harmless virus) will enter a cell in our body and then use the cell’s machinery to produce a harmless piece of the virus that causes COVID-19. This piece is known as a spike protein and it is only found on the surface of the virus that causes COVID-19.

The cell displays the spike protein on its surface, and our immune system recognizes it doesn’t belong there. This triggers our immune system to begin producing antibodies and activating other immune cells to fight off what it thinks is an infection. At the end of the process, our bodies have learned how to protect us against future infection with the virus that causes COVID-19. For more information, see Understanding Viral Vector COVID-19 Vaccines.

• birth year (not reported for people over 80 years old)
• sex
• the county where the vaccine is administered.

• No preservatives like thimerosal or mercury or any other preservatives.
• No antibiotics like sulfonamide or any other antibiotics.
• No medicines or therapeutics like ivermectin or any other medications.
• No human or animal tissues like aborted fetal cells, gelatin, or any materials from any animal.
• No food proteins like eggs or egg products, gluten, peanuts, tree nuts, nut products, or any nut byproducts (COVID-19 vaccines are not manufactured in facilities that produce food products).
• No metals like iron, nickel, cobalt, titanium, rare earth alloys, or any manufactured products like microelectronics, electrodes, carbon nanotubes or other nanostructures, or nanowire semiconductors.
• No latex. The vial stoppers used to hold the vaccine also do not contain latex.

Some people experience side effects after getting the COVID-19 vaccine. These side effects are common as the body builds cells to defend against COVID-19. They usually develop within 3 days of getting the vaccine and go away after a day or two. Side effects are more common after the second dose of a two-dose vaccine. 

Side effects in the arm where you got the vaccine may include: 

• Pain 
• Redness 
• Swelling 

Side effects throughout the rest of your body may include: 

• Tiredness 
• Headache 
• Muscle pain 
• Chills 
• Fever  
• Nausea 

There have been a few rare yet serious side  The CDC has determined that the benefits of getting vaccinated far outweigh the risks, and individuals can talk with their healthcare provider if they have questions about which vaccine is right for them.

Johnson & Johnson/J&J A rare but serious type of blood clot, called Thrombosis with Thrombocytopenia Syndrome (TTS), has occurred in a small number of people who have received the Johnson & Johnson COVID-19 vaccine. Cases of TTS have been reported in men and women of all ages with the highest rate in women between 30 and 49 years old (about 1 case per 100,000 doses). Eight (or 15%) of 54 people who have developed TTS have died. Symptoms usually begin within 2 weeks after vaccination.  You should seek immediate medical attention if you have any of the following symptoms after vaccination: shortness of breath; chest pain; leg swelling; persistent abdominal pain, severe headaches or blurred vision; easy bruising or tiny blood spots under the skin beyond the site of the injection.

An increased risk of TTS has not been seen with the mRNA vaccines, so the CDC now recommends that the Pfizer or Moderna vaccine is used in all eligible persons if possible, including for booster doses.

Guillain-Barré Syndrome (GBS) has also occurred in a small number of people who have received the J & J vaccine. GBS is a rare nervous system disorder in which the immune system damages the body’s own nerve cells, usually after getting certain types of infections. This can cause muscle weakness, or in the most severe cases, paralysis. The highest risk has been observed in men ages 50-64 years with symptoms of GBS beginning within 42 days after vaccination. You should seek immediate medical attention if you have any of the following symptoms after vaccination: weakness or tingling sensations, especially in the legs or arms, that are worsening and spreading to other parts of the body; difficulty walking; difficulty with facial movements, including speaking, chewing or swallowing; double vision or inability to move the eyes; or difficulty with bladder control or bowel function.

The Food and Drug Administration (FDA) has looked and at the available data and determined that the benefits of this vaccine still outweigh the risks. Visit the CDC's overview of J & J vaccine safety to learn more. 

Pfizer/Moderna

Cases of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the sac around the heart) have been reported after getting an mRNA vaccine. These cases have been mostly in male teens and young adults within a week of getting the second dose of vaccine. Most of the individuals who received care responded well to medicine and rest and quickly felt better. As of December 10^th 2021, over 7 million doses of the Pfizer vaccine have been given to children ages 5 to 11, and the CDC has confirmed 8 cases of myocarditis in this age group, mostly after Dose 2. You should seek medical care right away if you have any of the following symptoms after vaccination: chest pain, shortness of breath; or feelings of having a fast-beating, fluttering or pounding heart.

The CDC, the American Heart Association, the American Academy of Pediatrics and others still recommend that anyone 12 and over get vaccinated as the benefits far outweigh the risks. You can also visit the CDC’s Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination webpage to learn more.

Yes. COVID-19 vaccination is recommended for all persons 5 years of age and over, including persons who are pregnant, breastfeeding, trying to become pregnant, or may become pregnant in the future. Pregnant and recently pregnant persons are more likely to get severely ill with COVID-19 compared to non-pregnant persons. In addition, pregnant people are at increased risk of pre-term birth (delivering a baby before 37 weeks).  

Getting a COVID-19 vaccine can help protect pregnant and/or breastfeeding persons from severe illness from COVID-19. 

• Evidence about the safety and effectiveness of COVID-19 vaccination during pregnancy has been growing. These data suggest that the benefits of receiving a COVID-19 vaccine outweigh any known or potential risks of vaccination during pregnancy. 
• There is currently no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems in women or men. 
• Recent reports have shown that breastfeeding persons who have received COVID-19 mRNA vaccines (Moderna and Pfizer) have antibodies in their breastmilk, which could help protect their babies. 

• V-safe app from the CDC is a smartphone-based, after-vaccination health checker for people who have received the COVID-19 vaccine. V-safe uses text messaging and surveys to check in with COVID-19 vaccine recipients after vaccination. Simply put, anyone with symptoms enters their information into V-Safe so that researchers can continue to study the safety of the vaccine on all populations.
• The Vaccine Adverse Event Reporting System (VAERS) is a national system used by the CDC and the FDA. This system collects reports from healthcare professionals, vaccine manufacturers, and the public regarding any adverse events that may happen after vaccination.
• National Healthcare Safety Network (NHSN) is an acute and long-term facility monitoring system that reports to the Vaccine Adverse Events Reporting System (VAERS).
• Vaccine Safety Datalink (VSD) is a network of nine healthcare organizations from across the US that conduct active surveillance and research. This system is used to aid in determining if possible side effects identified in the VAERS are actually related to the vaccine.
• Clinical Immunization Safety Assessment (CISA) Project is a collaboration between seven medical research institutions and the CDC. CISA provides consultation on a case by case basis, and conducts research about vaccine safety.

Please wait until your quarantine period is over before getting vaccinated or boosted. This helps reduce the risk of potentially spreading the virus that causes COVID-19 to others during the vaccination visit.

Please continue to follow all COVID-19 safety measures and quarantine guidance.

The CDC does not recommend taking medications that treat fever and pain, such as acetaminophen or ibuprofen, before your vaccine to prevent side effects. These medicines might affect how well your body’s immune system responds to the vaccine. If you take these medications regularly for another health condition, talk to your healthcare provider before skipping any doses.

You can ask your healthcare provider about whether you can take these medications after vaccination for symptoms such as fever or arm pain. To soothe arm pain, the CDC also recommends applying a clean, cool, wet washcloth over the area where you feel discomfort and exercising your arm. If you experience fever, drink plenty of fluids and keep your body cool.

If you have COVID-19 or tested positive for SARS-CoV-2, you should wait to get your second dose until your symptoms have resolved (if you have symptoms) AND until you have finished your isolation period. Sometimes this will require rescheduling your second dose, but there is no need to retake the first dose.

Because vaccines are not 100% effective, the number of vaccine breakthrough infections will increase as the number of people who are fully vaccinated goes up. Fully vaccinated people with a vaccine breakthrough infection are less likely to develop serious illness than those who are unvaccinated and get COVID-19. Even when fully vaccinated people develop symptoms, they tend to be less severe symptoms than in unvaccinated people. This means they are much less likely to be hospitalized or die than people who are not vaccinated. However, people who get vaccine breakthrough infections can spread COVID-19 to others.

For information on booster doses, see Who should get a COVID-19 booster dose?
For California data, please visit Post-Vaccine COVID-19 Cases.
For national data, please visit COVID-19 Vaccine Breakthrough Case Investigation and Reporting.

Pfizer/BioNTech  

• 46,331 enrolled  

• 153 clinical sites in 39 United States  
• Racial/ethnic distribution:  

• 70% White  
• 13% Hispanic/Latino (>5.5k)  
• 10% African American/Black (>4k)  

• 6% Asian  
• 1% Native American  

• Age distribution:  

• 45% ages 56-85  

Moderna 

• 30,000 enrolled  
• 89 clinical sites in 32 United States  
• Racial/ethnic distribution: 

• 63% White  
• 20% Hispanic/Latino (6k)  

• 10% African American/Black (3k)  
• 4% Asian  
• 3% All others  

• Age distribution: 

• 39% ages 45-64  

• 25% ages 65+  

Janssen (Johnson & Johnson) 

• 43,783 enrolled 
• Racial/ethnic distribution: 

• 74% White 

• 15% Hispanic/Latino, 
• 13% Black/African American 
• 6% Asian 
• 1% American Indian/Alaska Native 

• Age distribution: 

• 66% ages 18-59 
• 34% ages 60+ 

If you would like to volunteer in a medical or non-medical role at one of the County’s vaccination sites, you must register online.

Non-medical volunteers: Please register with the California Health Corps here. Under Organization select “Alameda County Unit”. Under "Occupation" select "Non-Medical". You will be asked to submit to a brief background check.

Medical volunteers: Please complete both of the following registration forms.

Register with the California Health Corps here and be sure to sign up for the “Alameda County Unit.”

Sign up with Alameda Count through this electronic form. You will be asked to submit to a brief background check.

At this time, we are fortunate to have a large number of volunteer offers which may cause delays in our vetting system and background check process. We will process these as quickly as possible in anticipation of needing additional volunteers in the coming months as our vaccine allocation from the state increases. Thank you for your patience as this process ramps up.

In the coming months, we anticipate a need for vaccinators and logistical and administrative support. Dates and locations are not determined yet, but we do expect that one shift could be 8-12 hours long. There is no pay for volunteering. Modest meals will be provided, and volunteers could potentially receive the vaccine.

Thank you for your patience at this time. More information about volunteering can be found here.

• They are ages 12 and older and received their second dose of Pfizer at least 5 months ago or
• They are ages 18 and older and received their second dose of Moderna at least 5 months ago, or
• They are ages 5 and older, immunocompromised, and received their additional primary shot of Pfizer or Moderna at least 5 months ago, or
• They are ages 18 and older and received a first dose of Johnson & Johnson/J&J vaccine at least 2 months ago. Due to the risk of a rare (but serious) side effect of the J & J vaccine, the CDC recommends that individuals who received the J&J vaccine receive an mRNA (Pfizer or Moderna) booster dose. The J & J vaccine is still authorized by the FDA for those who prefer it or who are not able to receive the Pfizer or Moderna vaccine.

The Moderna booster is half the dose of the original vaccine series. The Pfizer and J&J boosters are the same dose as the first dose(s).

In alignment with the CDPH, visit MYTurn.ca.gov to find a location near you. You can also check with your healthcare provider or local pharmacy to see if vaccination walk-ins or appointments are available. You can also find vaccination locations at Where to get a Vaccine in Alameda County.

Please note that you do not need a note from your healthcare provider to receive aCOVID-19 booster. If you are part of any of the groups eligible for a COVID-19 booster, you may self-attest and receive a booster.

The COVID-19 vaccines are working well to prevent severe illness, hospitalization, and death due to COVID-19. Cases by vaccination status can be viewed here: https://covid-19.acgov.org/data.page?#vax-status. However, public health experts are starting to see reduced protection over time, especially among populations such as older adults and those with underlying medical conditions, against mild and moderate disease.

No. It is a moral and public health imperative to ensure that all individuals residing in the United States have access to the vaccine. Alameda County and the Department of Homeland Security (DHS) encourage all individuals, regardless of immigration status, to receive the COVID-19 vaccine once eligible under local distribution guidelines. For more information, please see DHS Statement on Equal Access to COVID-19 Vaccines and Vaccine Distribution Sites.

There is no cost associated with getting vaccinated against COVID-19— regardless of insurance, immigration status, or vaccine phase.

• Photo Identification (ID). Your photo ID does not have to be government issued.
• Appointment Confirmation. If you have an appointment, print the confirmation, or provide it on your phone.
• Mask. Please remember to wear a mask and practice social distancing.

Yes. Vaccinating as many people as possible helps reduce viral spread and limits opportunities for the virus to evolve variants of concern in our communities.

Please continue to follow the prevention guidelines you’ve heard about since the pandemic started:  

• Wear a face covering
• Keep at least six feet of distance from anyone you don’t live with
• Wash your hands oftenStay home if sick
• Avoid gatherings

There are three vaccines that are currently being administered in Alameda County. The vaccinator will provide you with information about which vaccine you are receiving and, depending on which vaccine you receive, when to get your second dose.

• The Pfizer-BioNTech vaccine consists of two doses given 21 days apart.
• The Moderna vaccine consists of two doses given 28 days apart.
• The Johnson & Johnson vaccine consists of one dose.

• The recommended time between Dose 1 and Dose 2 is 3 weeks (21 days) for Pfizer and 4 weeks (28 days) for Moderna. If it is not possible to get the second dose on time, it may be given up to 6 weeks (42 days) after the first dose. It is strongly encouraged to get the second dose on time.
• Getting a second dose more than 4 days early is NOT recommended.
• A person is still considered fully vaccinated if the time between first and second doses is longer than recommended.

Please report any adverse events or reaction to the vaccine to the Vaccine Adverse Events Reporting System.

Please report any vaccine administration errors to the Vaccine Errors Reporting Program.

Under most circumstances, the different vaccines should not be mixed. For example, you should not receive your first dose with the Pfizer vaccine and get your second dose with Moderna or Johnson & Johnson. Your healthcare provider or someone at the vaccine clinic will let you know if you need to get a different vaccine as your second dose. If you received the Johnson & Johnson vaccine, you do NOT need a second dose.

If you got the Pfizer or Moderna vaccine as your first dose, please bring your COVID-19 vaccination record card with you to your second vaccination appointment. It is recommended that you make a backup copy of your COVID-19 vaccination record card, such as taking a picture of your vaccination card with your phone.   

Additionally, your first vaccine dose is recorded in the California Immunization Registry (CAIR). Therefore, at your second dosing appointment you can ask your vaccine administrator pull up your information on CAIR to ensure vaccine mixing does not occur.

Alameda County’s indoor masking Health Officer Order No. 21-06 includes all workplaces and all indoor settings. Regardless of vaccination status, all persons in Alameda County are required to wear a face covering when indoors and in any workplace setting. For detailed information, please see Health Officer Order No. 21-06 Use of Face Coverings Indoors & In Workplaces FAQ (acgov.org)

Yes. If you have symptoms, you should get tested immediately and isolate if your test is positive. If you have been exposed to someone with COVID-19, you should get tested 5 to 7 days after the exposure and isolate if your test is positive. The vaccine does not affect the results of COVID-19 diagnostic tests, such as PCR or antigen tests. Anyone with symptoms of COVID-19 should be tested even if they were recently vaccinated.

Yes, please continue to follow the prevention guidelines you’ve heard about since the pandemic started, and please remember to get your second and/or booster dose:

1. Wear a face covering when you are with people you don't live with
2. Keep at least six feet of distance from anyone you don’t live with
3. Wash your hands often
4. Stay home if you are sick
5. Avoid gatherings with people you don't live with

The vaccine will protect you from developing severe illness, but it may not stop you from spreading COVID-19 to others if you become infected. Until we get enough people vaccinated to protect our entire community, it is critical that everyone—even those who have been vaccinated—continue to follow other COVID-19 prevention guidance, such as wearing masks. It is also important to get tested if you experience symptoms of COVID-19 or are exposed to someone who has COVID-19 and isolate if your test is positive.

• Been receiving active cancer treatment for tumors or cancers of the blood
• Received an organ transplant and are taking medicine to suppress the immune system
• Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
• Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
• Advanced or untreated HIV infection
• Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

Each vaccine dose for children ages 5-11 is less than the vaccine dose for those ages 12 and older. Children ages 5-11 will receive a lower dose vaccine (1/3 of the dose for adults and teens) and will receive the vaccine with a smaller needle. The two doses should be given 21 days apart just like in teens and adults.

Clinical trials demonstrated that the COVID-19 vaccine is safe and effective in children and teens ages 5 and older. On October 29^th, the U.S. Food and Drug Administration (FDA) extended the Emergency Use Authorization to include children ages 5 to 11, following a thorough review of data from their advisory committee. The CDC’s Advisory Committee on Immunization Practices and Western States Scientific Safety Review Workgroup also reviewed the data and supported the Emergency Use Authorization. Learn more about the process of developing, authorizing, and approving COVID-19 vaccines.

The science is clear: the benefits of COVID-19 vaccination outweigh the known and potential risks. Get a COVID-19 vaccine for children ages 5 and older as soon as you can.

After getting a COVID-19 vaccine, children and youth may have some side effects, such as:

• Sore arm
• Feeling tired for a day or two
• Muscle aches or headache
• Low grade fever
• Chills
• Upset stomach

Most side effects are mild and will go away in a few days. Side effects can be more intense after the second shot than the first.  Side effects happen as the body is building protection against the virus, but they should go away in a few days. If side effects do not improve, contact your child’s healthcare provider. 

COVID-19 infection and Multisystem Inflammatory Syndrome in Children (MIS-C) cause myocarditis at higher rates than the COVID-19 vaccine. Vaccinating children and teenagers protects them from COVID-associated complications, including myocarditis.

There have been cases of myocarditis (heart inflammation) and pericarditis (inflammation of the sac around the heart) among youth after getting an mRNA vaccine like Pfizer. These have been mostly in male teens and young adults within a few days of getting the second dose of vaccine. Most of the youth who received care responded well to medicine and rest and quickly felt better. As of December 10^th 2021, over 7 million doses of the Pfizer vaccine have been given to children ages 5 to 11, and  the CDC has confirmed 8 cases of myocarditis in this age group, mostly after Dose 2. The CDC and its partners are actively monitoring reports of myocarditis and pericarditis, by reviewing data and medical records, to learn more. Safety monitoring systems are in place to collect information if more cases are detected. 

Children and teens should seek medical attention right away if they have any of the following symptoms after receiving the COVID-19 vaccine:  

• Chest pain  

• Shortness of breath  
• Feelings of having a fast-beating, fluttering, or pounding heart. 

For more information, please visit the CDC website.

There are systems in place to monitor for adverse events and side effects of the vaccine in real-time, including:

• Enroll in the V-safe app from CDC. Parents and guardians can enroll children and youth ages 5 years and older in V-safe and complete health check-ins on their behalf after they have been vaccinated for COVID-19. Anyone 16 and over can enroll themselves. V-safe is a smartphone-based, after-vaccination health checker for people who have received the COVID-19 vaccine. V-safe uses text messaging and surveys to check in with COVID-19 vaccine recipients after vaccination. Simply put, anyone with symptoms enters their information into V-Safe so that researchers can continue to study the safety of the vaccine on all populations. 
• The Vaccine Adverse Event Reporting System (VAERS) is a national system used by the CDC and the FDA. This system collects reports from healthcare professionals, vaccine manufacturers, and the public regarding any adverse events that may happen after vaccination.
• National Healthcare Safety Network (NHSN) is an acute and long-term facility monitoring system that reports to the Vaccine Adverse Events Reporting System (VAERS).
• Vaccine Safety Datalink (VSD) is a network of nine healthcare organizations from across the US that conduct active surveillance and research. This system is used to aid in determining if possible side effects identified in VAERS are actually related to the vaccine.

• Clinical Immunization Safety Assessment (CISA) Project is a collaboration between seven medical research institutions and the CDC. CISA provides consultation on a case by case basis, and conducts research about vaccine safety.
• Learn more about how the safety of the COVID-19 vaccine is ensured.

• Get very sick from COVID-19, including requiring hospitalization. Children with underlying medical conditions are at higher risk for severe illness, but one-third of children and teens who are hospitalized have NO underlying medical conditions
• Develop serious complications like multisystem inflammatory syndrome (MIS-C)—a condition where different body parts become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs.
• Develop post-COVID complications, also called "long COVID".
• Spread COVID-19 to others, including vulnerable members of their family.

Vaccine doses are given by a child’s age, not their weight, because that’s how they were studied during clinical trials. The smaller dose was effective in all children, regardless of body mass index (BMI). Some children may be 11-years-old when they get their first dose and 12 at the time of their second dose. They should receive a dose based on their age on the day of vaccination.

Yes! COVID-19 vaccines and other vaccines can be given at the same time. If your child has missed recent vaccinations due to the pandemic, now is a great time to get caught up. Talk to your healthcare provider if you have questions about your child getting multiple vaccines at once.

Children ages 5-11 need consent from a parent or legal guardian, and should be accompanied by a parent, legal guardian or qualified relative (ages 18 and older) to and from the vaccination site. A qualified relative is defined as a spouse, parent, stepparent, brother, sister, stepbrother, stepsister, half-brother, half-sister, uncle, aunt, niece, nephew, first cousin, or any person denoted by the prefix “grand” or “great,” or the spouse of any of the persons listed in this definition.

Youth ages 12 and older need consent from a parent or legal guardian, but they do not need to be accompanied by an adult to the vaccination site.

You may read the full CDPH Pfizer Vaccine Minor Vaccination Guidance online or a summary of the guidance below. The ACPHD Pfizer Minor Consent Guidance is available on this website under “Resources.” 

Per the California Department of Public Health Pfizer Vaccine Minor Consent Guidance, anyone younger than 18 years (a “minor”) must have a parent or legal guardian consent on their behalf prior to receiving the Pfizer COVID-19 vaccine. A Relative Caregiver (e.g. someone who is 18 years or older and lives with the minor such as a grandparent, aunt, uncle, or cousin) may provide consent after completing a Caregiver Affidavit Form. 

An emancipated minor may consent for himself/herself/themselves. 

Unaccompanied minors* may consent to their own medical care if all of the following conditions are satisfied: 

(1) The minor is 15 years of age or older. 

(2) The minor is living separate and apart from the minor's parents or guardian, whether with or without the consent of a parent or guardian and regardless of the duration of the separate residence. 

(3) The minor is managing their own financial affairs, regardless of the source of the minor's income. 

*Unaccompanied minors are defined in U.S. law as children who cross our borders and (1) have no lawful immigration status in the U.S., (2) have not attained 18 years of age, and (3) have no parent or legal guardian in the U.S. or no parent or legal guardian in the U.S. who is available to provide for their care and physical custody. 

The process for developing and authorizing vaccines is well established. No steps were skipped in developing the COVID-19 vaccines, including in the clinical trials for children and youth ages 5-11 and 12-17. However, some of the steps were performed at the same time, thus speeding up the process.

No. COVID-19 vaccines do not interact with or change your DNA in any way. 

The vaccine manufactured by Pfizer is an mRNA vaccine. mRNA vaccines do not contain a live virus and do not carry the risk of causing an infection in the vaccinated person. mRNA from the vaccine never enters the nucleus of the cell and does not affect or interact with a person’s DNA. 

Some people who menstruate have noticed changes in their menstrual cycle around the time they got their COVID-19 vaccine. However, people can experience health issues following vaccination that would have happened even if they did not get vaccinated. There is currently no research suggesting that that any of the COVID-19 vaccines affect menses or the onset of puberty. However, both stress and illness can cause irregular menstrual cycles, and in the first few years after people get their periods, it’s not uncommon for their cycles to be irregular. Using an additional method of birth control may be important for some after vaccination. 

According to the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, there is no evidence that COVID-19 vaccines can affect the ability to get pregnant. While fertility was not specifically studied in the clinical trials of the vaccine, no loss of fertility has been reported among trial participants or among the millions who have received the vaccines since their authorization. In addition, no signs of infertility appeared in animal studies. 

Clinical trials of Pfizer COVID-19 vaccine were found to be safe and effective in protecting against severe illness, hospitalization, and death in children and youth ages 5-11 and 12-15.

Pfizer Clinical Trial Participant Summary, Children and Youth ages 5-11 

Pfizer’s  Vaccination was nearly 91% effective in preventing COVID-19 infection among children ages 5-11 years .

In the original enrollment group of 2,268 children:

• All participants were based in the United States
• Sex distribution:
  • 47% female
  • 53% male
• Racial/Ethnic distribution
  • 79% white
  • 21% Hispanic or Latino
  • 6% Asian
  • 6% Black or African American
  • 1% American Indian or Alaska Native
  • <1% Native Hawaiian or other Pacific Islander

Pfizer’s clinical trials for those ages 12 to 15 enrolled 2,260 children and youth in the United States. None of the youth who received the vaccine developed COVID-19.

Pfizer Clinical Trial Participant Summary, Children and Youth ages 12-15

• 2,260 enrolled, all based in the United States. 
• Sex distribution: 
  • 49% Female 
  • 51% Male 
• Racial/ethnic distribution: 
  • 86% White 
  • 12% Hispanic or Latino 
  • 6% Asian 
  • 5% Black or African American 
  • <1% American Indian or Alaska Native
  • <1 % Native Hawaiian or Pacific Islander, no participants in the Placebo

Similar to adults, those ages 5-17 will be fully vaccinated two weeks after receiving the second dose of the COVID-19 vaccine. The COVID-19 vaccine will help protect children and teenagers from severe illness, hospitalization and death from COVID-19.

Masks are one of the most effective safety measures to prevent in-school transmission of COVID-19. Indoor masking is required in K-12 schools by CDPH, regardless of vaccination status. In Alameda County, there is an  indoor masking requirement when indoors and in workplaces.

Vaccinated children and youth who have been exposed to someone with COVID-19 do not need to quarantine, as long as they remain symptom-free. However, they should get tested 5 to 7 days after exposure.

For detailed information, please see K-12 Guidance 2021-22 School Year (ca.gov)

The COVID-19 vaccine is free for all Alameda County residents, regardless of their immigration or health insurance status.

Check with your child’s healthcare provider about whether they offer COVID-19 vaccination. Alameda County parents and legal guardians can also schedule appointments for young people in their families 5 years of age and older to receive the Pfizer COVID-19 vaccine using the statewide and county booking system.

Make an appointment with an Alameda County site: AlCoVax Signup or call 510-208-4VAX