We have some friends who have chosen not to vaccinate their kids. We have gotten our child all of the vaccines recommended by their pediatrician. What are the risks of my kid interacting with their kid?
—JS
The individual child risk is low, especially for an older kid. By the time a child is 4, they will have had a full complement of vaccines. These vaccines are extremely protective. The measles vaccine, for example, is 99% effective after two doses. Pertussis, chickenpox, and polio are all similar.

This question becomes a bit more complicated if there are younger siblings, if your child is too young to be fully vaccinated, or if there is a lot of interaction with elderly people or those who are in other ways seriously immunocompromised. In some cases, like measles, vaccination is sterilizing. This means that a vaccinated child cannot get the disease but also cannot spread it.
Other vaccines do not work like this. Pertussis vaccination does a good job of protecting the vaccinated person, but it is still possible for them to spread the virus. This is less likely than if they were not vaccinated, but it can happen.
This is to say: there should be added caution if there are people who surround your child who might not be as well protected. But just from the individual child standpoint, the concern is minimal.
Community Guidelines
Log in
Could you describe the greater risks for babies and toddlers? My daughter is now 12mo and is up to date but my friends daughter is 3 months younger and they don’t want to fully vaccinate, specifically HepB
If your child’s immune system is intact, she should be protected against Hepatitis B by virtue of the completed series of Hepatitis B vaccines that she has had. However, your friend might be able to understand, if you “deep canvass” her, that the Hepatitis B virus can live in dried blood for weeks. Therefore, if there is dried blood, even microscopic, around the environment, her daughter is susceptible and is also capable of infecting others through the blood and body fluid pathway. If she has other friends who are unvaccinated, this is a real concern (and sometimes unvaccinated people flock together). And, if you do “deep canvass” her, you can also bring up the fact that the Hepatitis B vaccine is actually the first vaccine that was developed that prevents cancer. That’s right – since the Hepatitis B virus causes a form of liver cancer, preventing the virus prevents that form of cancer. The United States has made good progress against this virus by vaccinating babies; when we were only vaccinating “high risk” individuals, we were not able to reduce the prevalence of this disease. Kudos to you for being part of the solution and vaccinating your child!
Is Hepatitis B the only vaccine that your friend is avoiding?
Wow, thank you so much for this response! I did not know that the hepatitis B vaccine prevents cancer. I think the other vaccines she is avoiding are: Flu, RSV, and COVID. I believe it has something to do with politics around vaccines.