QUESTION

I’m 59 years old and don’t remember when I got my last tetanus shot. My doctor said I should get one. Can’t I just ask for the shot if I step on a rusty nail?

ANSWER

The vaccination guidelines for tetanus vary by country, and there are some misconceptions about the way that people can become infected. Tetanus is a serious bacterial infection that can be life-threatening if not treated promptly. The bacteria that cause tetanus, a condition commonly known as “lockjaw,” are typically transmitted via soil, dust or manure. Rusty nails are widely believed to cause tetanus, but that is somewhat misleading—rust itself does not necessarily carry the bacteria, but it’s long been assumed that any sharp object that’s rusty could have been exposed to dirt, dust or manure, for example, that contains the bacteria that cause tetanus.

In the US, the current recommendation by the Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts that advises the CDC on vaccination guidelines, is for adults to be revaccinated for tetanus every 10 years throughout adulthood. In other countries, such as the UK, there is no recommendation for adult booster vaccination against tetanus once a person has completed his/her childhood vaccination series because they are considered to be immune for life. The 2019 guidelines published by the World Health Organization (WHO) state that people have lifelong protection once they have received six doses beginning in childhood.

Researchers at Oregon Health & Science University analyzed whether adults need to receive a tetanus booster, which is commonly combined with a booster for the bacterial infection diphtheria, every 10 years. The study, which was published in Clinical Infectious Diseases, involved 546 adults and found that protective levels of circulating antibodies could be maintained for at least 30 years. Based on this finding, the researchers concluded that a simpler adult vaccination schedule—getting the shot at age 30 and again at age 60—would be effective after the childhood vaccine series is completed. An age-based system makes sense because most people don’t remember when they received their last tetanus shot, nor do they recall how many shots they received in the past.

If you don’t remember when you received your last tetanus shot (or if you don’t know whether you received the full childhood series), you should get a booster. While it is true that a booster dose may be given at the time you’re exposed to the bacteria as part of treatment to prevent severe disease, the vaccine works best when given before exposure, since this allows the immune system more time to develop protective levels of antibodies.

Even though tetanus is rare in the US (averaging about 29 cases per year), the majority of reported illnesses occur in people who did not receive the full childhood vaccination regimen or failed to complete their booster shots in adulthood. Side effects from the shot are rare, but may include fever and/or redness or swelling at the injection site. If you have any questions or concerns about your health or vaccination history, it is always a good idea to consult your doctor.