FREQUENTLY ASKED QUESTIONS
Yes. You should get the vaccine even if you have already had COVID-19. Some people have gotten COVID-19 more than once. The vaccine also offers more protection against reinfection than your body could develop on its own from already having COVID-19. You can get vaccinated as soon as you are out of your isolation period and are feeling better.
Information collected when you get the vaccine follows all HIPPA privacy requirements. The health department or medical provider will retain some information for dose tracking purposes. No information is shared with non-public health agencies.
The vaccine distributed at CDPH vaccination sites will be at no cost to the individual, regardless of whether they are uninsured or undocumented.
The Pfizer vaccine needs to be stored at an ultra-cold temperature and the Moderna vaccine needs to be stored at frozen temperature unless it will be used soon. Both will be defrosted before administering the shot. The Johnson & Johnson vaccine is stored at 36°F to 46°F (refrigerator temperatures).
The Pfizer-BioNTech and Moderna COVID-19 vaccines require two shots. For those vaccines, it is important to get both shots to gain the most protection. Before you leave the vaccination site, make an appointment to get the second shot 3-4 weeks after the first shot, depending on the vaccine. This is the best time to get your second shot if you can. The 2nd dose is just as effective if you get it up to 6 weeks after your first dose. Even after the 6 weeks, you can still complete your 2nd dose safely – scientists just aren’t sure if it is as effective as getting it within the 6 week time period.
The Johnson & Johnson COVID-19 vaccine just requires one shot, but the CDC has updated its recommendations for COVID-19 vaccines with a preference for people to receive an mRNA COVID-19 vaccine (Pfizer-BioNTech and Moderna), rather than the Johnson & Johnson vaccine. The Johnson & Johnson vaccine will continue to be available for those who are unable or unwilling to receive an mRNA vaccine. Additional information on the CDC's latest guidance is available here.
Until you are fully vaccinated (two weeks after your second dose of an mRNA vaccine or your J&J shot), you should wear a mask and practice social distancing.
Similar to the flu vaccine, it will take a few weeks after completing the COVID-19 vaccine before your body builds up the immune response to protect against COVID-19. If you receive a 2-dose vaccine, the full immune response is not completed until a few weeks after the 2nd dose. Even with the high efficacy of the vaccines, no vaccine is 100% protective. CDPH still recommends mask wearing, social distancing and washing your hands frequently, even if you have received the vaccine.
Receiving the vaccine does not increase your chances of spreading COVID-19. Getting the vaccine drastically decreases your risk of getting COVID-19, but it does not eliminate the risk. Therefore, you may still spread COVID-19 if you contract the virus after vaccination.
Persons should not be scheduled to receive the second dose earlier than recommended (i.e., 3 weeks [Pfizer-BioNTech] or 1 month [Moderna]).
However, second doses administered within a grace period of 4 days earlier than the recommended date for the second dose are still considered valid. Doses inadvertently administered earlier than the grace period should not be repeated.
The second dose should be administered as close to the recommended interval as possible.
However, if it is not feasible to adhere to the recommended interval and a delay in vaccination is unavoidable, the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines may be administered up to 6 weeks (42 days) after the first dose. There are currently limited data on efficacy of mRNA COVID-19 vaccines administered beyond this window. If the second dose is administered beyond these intervals, there is no need to restart the series.
Fully vaccinated refers to a person who has received their primary series of COVID-19 vaccines. People are considered fully vaccinated:
- 2 weeks after their second dose in a 2-dose series, such as the Pfizer or Moderna vaccines, or
- 2 weeks after a single-dose vaccine, such as Johnson & Johnson’s Janssen vaccine
If you don’t meet these requirements, regardless of your age, you are NOT fully vaccinated.
- "Up to date" means a person has received all recommended COVID-19 vaccines, including any booster dose(s) when eligible.
- "Fully vaccinated" means a person has received their primary series of COVID-19 vaccines.
The best time to get boosted is after 10 days without disease, or if asymptomatic, or after COVID symptoms are resolved (usually 10-14 days from the onset of symptoms).
The creation, purchase, or sale of vaccine cards by individuals is illegal and endangers public safety. Anyone with information regarding fraudulent COVID-19 vaccination cards can file a report by calling 1-800-CALL-FBI. Tips may also be submitted anonymously to tips.fbi.gov. Additional details are available at the FBI website.
The Centers for Disease Control and Prevention (CDC) recommends the COVID-19 vaccination for people who are pregnant, recently pregnant (including those who are lactating), who are trying to get pregnant now, or who might become pregnant in the future. CDC strongly recommends COVID-19 vaccination either before or during pregnancy because the benefits of vaccination outweigh known or potential risks.
The Centers for Disease Control and Prevention (CDC) recommends the COVID-19 vaccination for who are breastfeeding. COVID-19 vaccines cannot cause infection in anyone, including the mother or the baby, and the vaccines are effective at preventing COVID-19 in people who are breastfeeding. Recent reports have shown that breastfeeding people who have received mRNA COVID-19 vaccines have antibodies in their breastmilk, which could help protect their babies. More data are needed to determine what protection these antibodies may provide to the baby.
While fewer children have been sick with COVID-19 compared to adults, children can be infected with the virus that causes COVID-19, can get sick from COVID-19, and can spread the virus that causes COVID-19 to others. Getting vaccinated is the best way to protect your children and those around them from COVID-19.
The Pfizer COVID-19 vaccine is over 90 percent effective at preventing COVID-19 in children ages 5 through 17 years.
Clinical trials, with thousands of volunteers, showed the Pfizer COVID-19 vaccine to be safe and effective for children age 5 and up. As with all COVID-19 vaccines, every study, every phase, and every trial to determine the vaccine is safe for children was reviewed by the FDA and a vaccine safety group. The CDC continues to monitor the vaccine for safety. They have identified no concerns about long term impacts. There is no evidence that the vaccine impacts puberty or reproductive development in any way.
The Pfizer COVID-19 vaccine is the only vaccine approved for youths age 5-17.
No. The COVID-19 vaccines were created quickly, but scientists have been working on this technology for 10+ years. Scientists all over the world worked together and shared information – in a way that has never been seen before – to address the COVID-19 crisis and create these vaccines.
The vaccine studies, including those for youth, had thousands of volunteers and showed that the Pfizer COVID-19 vaccine is safe and effective for those age 5 and up. The CDC continues to monitor the vaccine for safety.
Since April 2021, there have been less than one thousand confirmed reports of cases of inflammation of the heart – called myocarditis and pericarditis – happening after mRNA COVID-19 vaccination for people under 30. These reports are rare given the hundreds of millions of vaccine doses administered.
CDC and its partners are actively monitoring these reports, by reviewing data and medical records, to learn more about what happened and to see if there is any relationship to COVID-19 vaccination. Most patients who received care responded well treatment and rest and quickly felt better. Cases of myocarditis or pericarditis have been predominantly in males age 12-29 years. Symptoms (including chest pain, pressure, heart palpitations, and difficulty breathing after exercise or when lying down) typically develop within a few days after receipt of the second dose of vaccine.
CDC continues to recommend COVID-19 vaccination for everyone 5 years of age and older, given the greater risk of COVID-19 illness and related, possibly severe complications. Talk to your healthcare provider if you have concerns about myocarditis.
The CDC continues to monitor the COVID-19 vaccine for safety. They have identified no concerns about long term impacts. There is no evidence that the vaccine impacts puberty or reproductive development in any way.
Vaccines prevent disease by helping your body form a “memory” of it, so if you were ever exposed to the virus, your body would know how to fight it.
Things to know about the Pfizer mRNA vaccine:
- mRNA vaccines do not use the live virus that causes COVID-19. They CANNOT give someone COVID-19.
- mRNA vaccines DO NOT affect or interact with our DNA in any way.
We get it. Getting a shot is no fun. However, the protecting your child and the people around them from COVID-19 is worth it.
There may be some temporary side effects, like soreness at the injection site, feeling tired, or having a headache. All are signs that the body is building protection for COVID-19.
Dr. Arwady, Commissioner of the Chicago Department of Public Health, answers a frequently asked COVID question of the day.
There is no possibility that you can get COVID-19 from any of the COVID-19 vaccines.
ThePfizer and Moderna vaccines use mRNA to train the body to respond to the COVID virus without using any live virus. The mRNA used in these vaccines is code for a protein that is specific to the COVID-19 virus but does not cause any harm to you. Watch this Behind the Science video for more information.
The Johnson & Johnson vaccine uses an inactive, non-replicating vector virus that teaches your body how to fight off COVID-19. Watch this Behind the Science video for more information.
Yes. Nearly 255 million people in the United States have received at least one dose of a COVID-19 vaccine. Pfizer, Moderna, and J&J COVID-19 vaccines have undergone the most intensive safety monitoring in U.S. history. You cannot get COVID-19 from any COVID-19 vaccine. You may have some side effects after COVID-19 vaccination, but they should go away in a few days. No long-term side effects have been detected. There is no evidence that COVID-19 vaccines impact puberty or reproductive development in any way.
The CDC has updated its recommendations for COVID-19 vaccines, with a preference for people to receive an mRNA COVID-19 vaccine (Pfizer-BioNTech and Moderna). The CDC’s statement is available here. According to the CDC and the ACIP (Advisory Committee on Immunization Practices), due to both higher vaccine effectiveness of mRNA vaccines and some rare adverse events associated with the Johnson & Johnson vaccine, the risk/benefit analysis makes the mRNA vaccines a better choice than the J&J vaccine. The Johnson & Johnson vaccine is still available for those who are unable or unwilling to receive an mRNA vaccine, and adverse side effects are rare.
The Pfizer, Moderna, and Johnson & Johnson vaccines have completed multiple stages of clinical trials and were given emergency use authorization (EUA) by the U.S. Food and Drug Administration (FDA). The Pfizer vaccine has been approved for those 5 and older, and the Moderna and J&J vaccines for those 18 and older. The CDC, along with the FDA and other federal partners, will use established safety systems to conduct heightened safety monitoring of COVID-19 vaccines. Additional safety measures include active surveillance using text messaging and web surveys from CDC and enhanced passive surveillance through other data sources from healthcare facilities.
Public health officials will continue to monitor the safety and side effects of the COVID-19 vaccines, and will take appropriate actions to determine if recommendations for vaccine use should change thereafter.
If you received the Johnson & Johnson vaccine more than 3 weeks ago, you should have no concern about side effects. You should, however, look to get an mRNA vaccine booster 2 months after your J&J vaccine.
If you received the Johnson & Johnson vaccine within the last 3 weeks, however, and you experience symptoms such as severe headache, abdominal pain, leg pain or weakness, or shortness of breath, you should contact your health provider right away. Risks for severe outcomes are higher in women from 30-49 years old, but additional data collected over the past 6 months has revealed that the risk was higher than initially thought for men and women in all age groups.
You can find the ingredient lists of all vaccines on their websites. None of the vaccines contain the live virus that causes COVID-19. Instead, these vaccines contain “instructions” from the virus so that your body can learn how to create the proteins needed to fight it.
Data suggest current vaccines will be effective and safe in providing protection against COVID-19 variants.
Having some side effects isn't necessarily a bad thing. Vaccinations may cause mild COVID-19-like symptoms, but this is a sign your immune system is responding to the vaccine. The vaccine does not contain a live virus and cannot give you COVID-19. The most common side effects are fever, chills, tiredness, or headache. At the injection site, you may experience pain, redness or swelling. Although these side effects may be unpleasant for 1-3 days, they are not dangerous. People with history of significant allergic reactions to vaccines, food, or medicine should consult with their doctor before receiving the vaccine.
The Johnson & Johnson vaccine, however, has recently been associated with some rare adverse effects; if you have received the J&J vaccine within the past 3 weeks and experience symptoms such as severe headache, abdominal pain, leg pain or weakness, or shortness of breath, you should contact your healthcare provider right away. Risks for severe outcomes are higher in women 30-49, but are present for both men and women in all age groups as well.
Both the Pfizer and Moderna vaccines are about 90-95% effective at preventing illness from COVID-19.
The Johnson & Johnson's overall efficacy against symptomatic COVID-19 infection was around 66%. This vaccine was 93% effective at preventing hospitalization from COVID-19 infection in the trials.
In an emergency, like a pandemic, it may not be possible to have all the evidence that the FDA would usually have before approving a drug, device, or a test. When there is a declared emergency, the FDA can allow the use of a product, like a vaccine, before full approval by issuing an Emergency Use Authorization or EUA.
After the requisite determination and declaration have been issued, and after feasible and appropriate consultations, FDA may issue an EUA only if FDA concludes that the following four statutory criteria for issuance have been met.
- Serious or Life-Threatening Disease or Condition
- Evidence of Effectiveness
- Risk-Benefit Analysis
- No Alternatives
More information on EUA is available on the FDA website.
The COVID-19 vaccine was developed through the Health and Human Services’ Operation Warp Speed. No safety measures were cut in its design, testing or manufacturing. A focus was placed on early manufacturing and the use of new technologies so as soon as the vaccine was deemed safe by the appropriate agencies, distribution could begin. More information about Operation Warp Speed is on the HHS' website.
Pfizer’s clinical trial enrolled 43,000+ participants with 42% globally having racially and ethnically diverse backgrounds. Moderna’s 30,000 trial included participants from minority communities, including 6,000 Hispanic and 3,000 Black participants. AstraZeneca’s initial trial data included participants from Brazil and the United Kingdom while the company continues to conduct trials in South Africa, Kenya, Latin America, Japan, Russia and the United States.
The Johnson & Johonson vaccine trial enrolled over 40,000 clinical participants; 17% identified as Black and 45% identified as Hispanic or Latino.
You can tell the CDC if you have any side effects after getting the COVID-19 vaccine through their website v-safe. V-safe is a smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after you receive a COVID-19 vaccination. Depending on your answers, someone from CDC may call to check on you and get more information. And, v-safe will remind you to get your second COVID-19 vaccine dose if you need one. Your participation in CDC’s v–safe makes a difference — it helps keep COVID-19 vaccines safe.
The Centers for Disease Control and Prevention (CDC) recommends urgent action to increase Coronavirus Disease 2019 (COVID-19) vaccination among people who are pregnant, recently pregnant (including those who are lactating), who are trying to become pregnant now, or who might become pregnant in the future. CDC strongly recommends COVID-19 vaccination either before or during pregnancy because the benefits of vaccination outweigh known or potential risks.