People caught up in the tragedy of Hurricane Harvey face uncertainty and stress. But one thing most of them don’t have to worry about right now is whether they need a tetanus shot.
Scattered social media posts from Texas have invoked the importance of tetanus shots for those who have been wading through floodwaters; a U.S. congressman urged residents to start considering whether they needed to get booster shots.
Those suggestions are based on the widespread belief that contact with floodwaters increases a person’s risk of contracting tetanus, a potentially fatal infection.
That, health experts say, is simply untrue.
“It’s this old wives’ tale. It’s a myth,” Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, told STAT.
Osterholm expressed concern that public health authorities in the affected parts of Texas and Louisiana — and in places taking evacuees from the flood zone — would try to mount mass tetanus vaccination efforts.
Doing so would divert resources that are needed elsewhere and unnecessarily alarm people who are already engulfed in a highly stressful situation, Osterholm said.
The Centers for Disease Control and Prevention does not recommend tetanus shots for people who have been in floodwaters. “Exposure to flood waters does not increase the risk of tetanus, and tetanus immunization campaigns are not needed,” the CDC website states.
Still, the perception that flooding increases the risk of tetanus is widespread.
Dr. Kathleen Schrank, a professor of emergency medicine at the University of Miami, said people do get panicky about tetanus shots after natural disasters, even though the concern is generally unwarranted.
“The idea of vaccinating the whole population or putting out any kind of suggestion to the public to come in for a tetanus shot should not be done,” she said.
Schrank recalled that after Hurricane Andrew, which walloped Miami 25 years ago — the anniversary was last Thursday — the demand for tetanus shots swamped the health care system.
“People think of it themselves and suddenly get very panicked about it,” she said. “So they go seek care for it and that overwhelms the local clinic or urgent care centers or health departments at a time when they need to be focused on much more likely threats.”
The widespread belief may stem from the fact that being in floodwaters — which can be full of debris and too murky to see through — does increase a person’s risk of experiencing a puncture wound.
Taking part in the cleanup operations that follow these disasters also carries increased risk of puncture wounds.
Both the CDC and the Occupational Health and Safety Administration recommend that workers involved in flood cleanups ensure that their tetanus vaccination status is up to date.
Tetanus is caused by Clostridium tetani, a spore-forming bacterium that is found in soil. When those spores enter the body — often through a puncture wound — the bacteria start to produce toxins that can cause serious health problems.
The toxins induce painful muscle contractions, especially in the jaw and neck. The term “lockjaw” actually refers to tetanus infection.
The fatality rate is high — the CDC says one or two out of every 10 cases is fatal.
But tetanus infections are rare; the U.S. averages only about 30 cases a year. That’s largely due to the fact that there is an effective tetanus vaccine. Vaccine protection, however, requires booster shots every 10 years.
People often forget when they were last vaccinated and when they are due for a tetanus booster. In decades past, the concern that people caught up in flooding might have let their tetanus protection lapse led to recommendations to vaccinate after floods and hurricanes, Osterholm said. But that didn’t always happen and yet there were no surges in tetanus cases after these natural disasters.
“As we looked at this more closely, in fact, even though punctures surely can occur, there’s absolutely no evidence that people are at more risk,” he said.
In addition to straining resources, trying to vaccinate large numbers of people could impede response and recovery efforts. Tetanus shots can hurt; sore arms are common for a couple of days after vaccination.
Osterholm recalled the response to a 1997 flood in Minnesota in which he urged public health responders to stop mass tetanus vaccination efforts. “We had people sand bagging,” he said. “And the next day their arm would hurt so much they almost couldn’t sand bag.”
Schrank said people in the flood zone who are concerned about tetanus should make a mental note to check their vaccination status within the next year and get a booster shot if they are due.
But she also cautioned that people who do sustain wounds during the flooding and its aftermath should get care if they need it.
“If you do develop a wound in your skin that develops an infection, yes, by all means go get medical care for it. Because there might be a need for antibiotics,” she said.
“Somebody needs to look at it and determine if it’s an actual infection or not. I don’t want to see people ignore [real] things. But the tetanus need is going to be minimal.”