(HealthDay News) — If you’ve suffered from tetanus — lockjaw — in the past, that doesn’t mean that you’re immune to it. You still should be vaccinated against the disease, according to the New York City Department of Health and Mental Hygiene.

Tetanus is a bacterial infection that causes painful muscle spasms. Due to widespread vaccine use, tetanus is rare in the United States, where it most often occurs in older people, farm workers and heroin users.

People contract tetanus when a wound becomes contaminated with Clostridium tetani bacteria, which is commonly found in soil contaminated with manure. Symptoms include a stiff jaw and neck, difficulty swallowing and rigid abdominal muscles.

Other symptoms include painful muscle spasms lasting for several minutes, fever, sweating and rapid heart rate.