Do flu shots have formaldehyde in them?

Yes, some flu shots contain formaldehyde, but only in trace amounts. Formaldehyde is a colorless gas with a strong odor that is used as a preservative in many vaccines, including flu shots. It helps to kill bacteria and viruses and prevent them from growing in the vaccine.

The amount of formaldehyde in flu shots is very small, typically around 0.01%. This is much lower than the amount of formaldehyde that people are exposed to in everyday life, such as from car exhaust, cigarette smoke, and household cleaners.

Formaldehyde is considered safe when used in small amounts, and there is no evidence that it causes any health problems when used in flu shots. However, some people may be allergic to formaldehyde, so it is important to talk to a doctor before getting a flu shot if you have any concerns.