Vaccination FAQs
What research supports that vaccines are safe?
An overwhelming number of studies by today's leading organizations and top scientists have shown that today's vaccines are safe and effective at preventing disease and infection. See the Children's Hospital of Philadelphia for more details on supporting research.
What organizations agree that vaccines are safe?
The New York State Department of Health, along with the American Academy of Pediatrics, the American Medical Association, the American Academy of Family Physicians, the National Association for Pediatric Nurse Practitioners, the Children's Hospital of Philadelphia, the Gates Foundation, the Infectious Diseases Society of America, the Canadian National Advisory Committee on Immunization, the Department of Health of the United Kingdom and many other reliable organizations around the world all agree vaccines are safe and save lives.
Is thimerosal safe?
Yes. Thimerosal is a vaccine preservative that prevents contamination of vaccines by germs. It has been well-studied and has not been shown to cause harm. Today, thimerosal is not used in any routine childhood vaccines, except for some multidose flu vaccines. Even for flu shots, thimerosal-free options are widely available. And even with the seasonal flu vaccine, thimerosal-free versions are available. Because of public concerns, most vaccines in the United States are now made without thimerosal.
How can flu vaccines come out so fast and still be safe?
Most Vaccines take 10-15 years of research, development, and testing before they are approved by the U.S. Food and Drug Administration (FDA). The flu vaccine is different, but not because the process is rushed. Each year, the manufacturing process for the flu vaccine stays the same. The only thing that changes each year is the antigen, the part of the vaccine that teaches your immune system what the flu virus looks like. Scientists worldwide track flu viruses year-round. Based on this global surveillance, experts predict which strains are most likely to spread in the upcoming seasons. The antigen is updated to match those strains, but the rest of the vaccine remains unchanged. The College of Physicians of Philadelphia provides a comprehensive explanation on how vaccines are developed (historyofvaccines.org) and are rigorously validated.
Because the process is the same every year and has been used safely for decades, manufacturers can update the flu vaccine quickly without skipping any safety steps. Flu vaccines still go through quality checks and must meet FDA safety standards every season.
If you're a parent with questions, the AAP offers information specific to childhood vaccines (aap.org). If you want to learn more about how vaccines are developed and tested, the College of Physicians of Philadelphia offers easy-to-understand information at historyofvaccines.org.
Why are there so many more vaccines today compared to when I was a kid? (cdc.gov)
As science and medicine continue to evolve, so does our ability -- and public health responsibility -- to prevent disease. Some of these advancements have led to new vaccines. The current U.S. vaccination schedule for children between birth and 6 years old recommends immunizations against at least 16 diseases that can cause serious health problems and even death. Although this number may seem high, it's essential to know that each disease can quickly reappear if vaccination rates drop. As vaccine development methods have become more sophisticated, the number of antigens in vaccines has decreased, even as more vaccines are added to the schedule
How are vaccines made and tested?
The development and evaluation of vaccines are among the most sophisticated medical processes in the world. Vaccine development is highly regulated, requiring years of research and testing before it's licensed for public use. The vaccine is first tested in the laboratory; if successful and effective, it is then tested in several clinical trials involving groups of volunteers. The plant where the vaccine is manufactured, as well as the process used to make it, is also inspected. Even after the U.S. Food and Drug Administration has approved a vaccine, the vaccine continues to be analyzed regularly, and there are international systems in place to track outcomes. For more information, see Vaccine Science: Process of Vaccine Development (Children's Hospital of Philadelphia.)
What are the side effects of vaccinations?
The most common side effects are:
- a low-grade fever
- mild body aches
- swelling, redness, or soreness at the injection site.
These reactions are normal and indicate that the vaccine is working and that the body is building protection. In very rare cases, a person could have an allergic reaction and should seek medical attention. This only happens to one in 1 million people.
It's also important to know that the flu vaccine cannot give you the flu. The viruses in the flu shot are either inactivated (killed) or made from only a tiny piece of the virus that cannot cause infection. For more information, see: Vaccine Adverse Events: Separating Myth From Reality (AAFP.)
Where can I get my child vaccinated?
Visit your child's pediatrician for personalized care and to get the appropriate vaccines. The New York State Vaccines for Children Program also provides vaccines at no cost to eligible residents; visit our Vaccines for Children Program page, email nyvfc@health.ny.gov or call 800-543-7468 for more information. You can also receive vaccinations at your local county health department.
Do vaccines cause autism?
No. Vaccines do not cause autism. This has been studied very carefully for many years, and large, well-designed medical studies have found no link between vaccines and autism.
Does my child really need a flu vaccine every year?
Yes. It is recommended that everyone aged 6 months or older receive a seasonal flu vaccine annually. Children are particularly at risk for contracting the flu because of the time they spend at school and play. Getting vaccinated is even more critical if your child has a chronic condition, like asthma or diabetes, that makes them more prone to being infected and can make their chronic condition worse. Nearly 20,000 children under age five are hospitalized in the United States every year due to flu-related complications, and many of these cases result in death. Avoid the possibility of this happening to your child.
How bad is it to delay the recommended vaccine?
The more you delay, the more you increase your risk of exposure to a long list of severe, potentially crippling, or deadly diseases. There are many consequences to delaying or not following the vaccination schedules recommended by the New York State Department of Health and the American Academy of Pediatrics. To find out more, see The Harm of Delaying or Skipping.
What does it mean if my child has a fever after getting vaccinated?
A mild fever that goes away in a day or two is not uncommon. Mild fever is actually a sign that the vaccine is working. However, if the fever persists, or increases in temperature, or if your child is exhibiting other symptoms that the nurse or pediatrician did not mention, seek medical attention promptly.
Does my child really need to get vaccinated against diseases that no longer exist?
Yes. Infectious diseases, by nature, spread quickly among those who are not protected. Even if the disease is considered rare or under control, it can still reemerge. We've seen this before, in the recent U.S. mumps, measles, and whooping cough outbreaks following drops in vaccination rates, which resulted in severe health consequences for many patients as well as a public health scare.
