The Hidden Health Costs of Hurricanes » Yale Climate Connection

In the weeks after Hurricanes Milton and Helen devastated the Southeast, photos of devastated communities are emerging.

We can easily see the damage caused by threats commonly associated with hurricanes and tropical storms: wind, waves, and flooding.

But the lingering health problems left in the wake of these storms are mostly invisible, harming people's well-being and increasing their risk of illness in insidious and silent waves. From the immediate risk of disruption to medical services to the slow worsening of pre-existing chronic conditions, these events can have devastating health impacts, and official death tolls are just the tip of the iceberg. New research shows that a given major hurricane could kill more than 7,000 people within 15 years of the storm receding.

But the good news is that recognizing the full range of health threats can help families, communities and health care systems prepare and recover long after landfall.

Direct Health Risks: Direct Injury and Contamination

When a hurricane strikes, the immediate risk of physical harm often dominates our attention.

Debris moved by wind or water can cause anything from minor cuts to severe trauma. Flooding can lead to drowning, and downed power lines and floodwaters pouring into homes can cause electric shocks.

Less obvious is that floodwaters can be mixed with dangerous pollutants: industrial chemicals, fossil fuels and sewage can turn the water into a toxic soup. Contact with contaminated water can cause skin injuries and infections, especially in people with open wounds. Exposure to floodwaters contaminated with human or animal feces also increases the risk of gastrointestinal illness.

Read: What should you do during a flood? Stay away from water.

Researchers used data from Hurricane Harvey in Texas in 2017 to compare emergency room visit rates in areas with low, moderate and high hurricane impact based on flood volume. They found that there were fewer emergency room visits on the day of the hurricane. This is not surprising since many people may not be able to leave their homes during a hurricane and many others may have been evacuated from their communities.

But soon after the disaster, they found higher rates of doctor visits for carbon monoxide poisoning in areas prone to flooding, which could be related to exposure to malfunctioning or damaged equipment or operating generators caused by flooding. They also found higher rates of drowning and hypothermia.

Short-term health impacts: hospitalization and health system risks

Health effects often change in the days or weeks after a hurricane.

The stagnant water left behind can become a breeding ground for mosquitoes, which can carry dengue fever, West Nile virus and other mosquito-borne diseases. Flooded homes can also lead to mold blooms that can lead to respiratory illnesses.

Other types of infections are also likely to surge. Data from the Florida Department of Health shows an increase in Vibrio vulnificus infections following recent hurricanes. These microorganisms, commonly known as flesh-eating bacteria, are often found in warm salt water and are especially dangerous for people with cuts or wounds. When hurricanes force seawater into freshwater canals and rivers, more people can come into close contact with the bacteria.

A study using Medicare data from 1999 to 2014 identified several trends in hospitalizations for patients over age 65. injuries, infectious diseases, and even some neurological disorders. On the other hand, data shows fewer people are being hospitalized for cancer. Although it is not clear why this is the case, it could be that pre-planned treatments were postponed due to damage to hospital infrastructure or appointment communication issues following major flooding.

Another study of 19 million premature births in the eastern United States from 1989 to 2002 found that pregnant women who experienced hurricanes had an increased risk of preterm birth. The risk is particularly high among already marginalized communities.

Hurricanes can also harm health by damaging critical healthcare infrastructure. Severe storms often disrupt hospitals and health systems in their path, causing power outages, denying access to clean water, contaminating equipment and medications, and forcing evacuations. Even if facilities remain open, damaged roads can prevent safe access to care.

In the aftermath of Hurricane Helene, the U.S. Department of Health and Human Services declared a public health emergency in the Southeast. With severe flooding in many parts of the region threatening to contaminate and damage hospitals, nursing homes, dialysis centers and other infrastructure, the department deployed more than 400 personnel to strengthen health care services and ensure the safety of these facilities.

In addition to causing damage to health infrastructure, storms can disrupt health care supply chains, leading to health impacts far away from the site of damage. Hurricane Helene severely damaged a facility in North Carolina that is a major supplier of intravenous fluids to the U.S. healthcare system, worsening a nationwide shortage of intravenous fluids that has been a major problem. The shortage has caused surgeries, dialysis and other types of health care to be delayed nationwide, even in places far from the hurricane's direct impact.

Long-term health effects: Chronic disease and mental health conditions

Chronic disease and mental health impacts can linger long after floodwaters recede.

A recent study by economists and public policy experts estimates that deaths in the days to weeks after a storm reflect only a fraction of the early deaths that occur long into the recovery process. When researchers looked at death data for the populations left behind, they found early deaths year after year—long after visible signs of hurricane damage may have disappeared. These are called indirect deaths – deaths caused by exacerbation of a chronic disease that, for example, could be avoided if the use of medical equipment that relies on electricity, such as oxygen for emphysema patients or frozen insulin for diabetics, had not been disrupted of. These impacts can last up to 15 years after the storm passes.

To come to this conclusion, the researchers analyzed data from 501 storms that hit the United States between 1930 and 2015. The analysis found that official death tolls in the weeks to months after the event significantly underestimated indirect deaths among hurricane survivors. Their modeling suggests that more than 7,000-11,000 annual deaths may be linked to each storm, a number that is 300 times higher than the official death toll.

The researchers speculate that the “excess” deaths they found may be due to worsening chronic disease management after a life-changing event, which may worsen heart disease or lead to chronic mental health challenges. They also point to social and economic factors that have significant downstream impacts on health. For example, in the decades following a major storm, regions that must invest in rebuilding damaged infrastructure may invest less in health support programs.

Evidence from surveys of survivors of Hurricane Maria in Puerto Rico in 2017 is consistent with the findings. Hurricane Maria was a Category 5 storm that caused severe damage to the island. The official death toll was 64, but subsequent studies, one of which collected extensive survey data from survivors, suggested that more than 4,600 additional deaths occurred after the storm, more than 70 times the official estimate.

Researchers found that many people spent extended periods of time without water and electricity, and many were unable to access basic medical services such as prescription refills. People living in regional areas are worse off than in city centres.

The invisible scars of mental health issues compound physical health risks. More than a decade after Hurricane Katrina devastated New Orleans, one in six survivors still exhibit symptoms consistent with post-traumatic stress disorder (PTSD). But even a diagnosis like post-traumatic stress disorder (PTSD) ignores broader mental health issues and emotional stress that may not meet the criteria for a specific diagnosis but may affect people's daily lives.

Preparing for the future: building resilience

As climate change-induced hurricanes become more intense, the impacts on health and healthcare systems will continue to be felt.

The trauma caused by a devastating hurricane can have ripple effects that span decades. For patients, without important medications or interventions, health conditions may deteriorate and recovery may be difficult.

It may be helpful to let your doctor know about being exposed to a major storm. For example, health providers have recognized that housing conditions, early childhood trauma, and transportation conditions can all have long-term effects on health. Health systems may need to begin to address exposure to climate hazards and provide additional support services to address the significant long-term health problems that may arise years after these destabilizing events.

Leveraging data on these impacts (short- and long-term), understanding which communities are at greater risk, and investing in strong health system infrastructure are critical to preparing for and minimizing widespread health risks.