New Estimate Puts Hurricane Maria Deaths in Puerto Rico over 5,000

The first estimate of deaths caused by Hurricane Maria’s landfall in Puerto Rico was 64. There were, at that point, just 64 confirmed deaths in the U.S. territory.

Later, as communication with rural areas was restored, that number grew. Deaths from contaminated water, deaths of individuals in Intensive Care units which had no electricity to keep essential equipment running, and deaths attributed to simple lack of health care brought estimates up to 1,000.

A new study published in the New England Journal of Medicine reports a much higher number: 4,645 or more.

Researchers surveyed 3,299 randomly-chosen households across Puerto Rico.

Excess deaths

One method of estimating hurricane-related deaths is the “excess deaths” method. Researchers compared the number of deaths directly after Hurricane Maria with the number of deaths for the same time period in the previous year. The normal death rate, taken from records in 2016, was 62% lower than the death rate in 2017.

This indirect means of tracking deaths is necessary because official death counts in Puerto Rico rely on the Institute of Forensic Sciences. Victims must be taken to San Juan, or a medical examiner must examine the victims by traveling to their location. In many cases, this was not possible, and hurricane victims were not certified.

Following the hurricane, transportation and communication continued to be problematic. Identifying cause of death was also difficult. Examiners often had no way to determine the medical care involved, or the connection with Hurricane Maria.

Researchers asked surveyed households about displacement and infrastructure loss as well as cause of death.

Lack of health care

One of the difficulties in coming up with accurate numbers is in definition. Someone who was swept out to sea during the hurricane certainly died from the hurricane. However, someone who died because electricity was not restored to a dialysis machine is not as clearly a victim of the hurricane in the traditional sense.

Researchers in the new study, which was largely funded by the Harvard T.H. Chan School of Public Health, were able to determine when deaths were the result of inadequate health care caused by the devastation of the hurricane and the slow recovery efforts.

Definitions from the the Centers for Disease Control and Prevention, which is the organization primarily in charge of tracking death rates in the United States, say that “deaths can be directly attributed to a tropical cyclone if they are caused by forces related to the event, such as flying debris, or if they are caused by unsafe or unhealthy conditions resulting in injury, illness, or loss of necessary medical services.”

Researchers had the medical knowledge to be able to pinpoint cases involving “unsafe or unhealthy conditions” as well as those caused by “loss of necessary medical services.”

“Representative community-based sampling remains one of the more robust and persuasive approaches to quantifying the effect of disasters and can effectively capture deaths indirectly attributed to disasters,” researchers concluded. “Despite the limitations and biases associated with data reported by participants, surveys can provide an independent estimate of mortality that does not rely on death-certificate data.”


Interviewers visited an evenly-distributed, randomly chosen groups of houses in all the municipalities in Puerto Rico. 93.4% of households agreed to be interviewed and completed the survey. When a house was empty, or if residents refused to be interviewed, interviewers used a random number generator to choose a replacement house among all visible households.

This method is much more in-depth than previous attempts to identify casualties of the hurricane. Since remote areas were included, the level of lack of electricity, passable roads, safe drinking water, and telecommunication were higher than news reports from San Juan and other major population centers.

Nonetheless, lack of access to health care was found across the island. “Considerable disruptions to medical services were reported,” researchers noted. 14.4% of households were unable to get prescription medicines, 9.5% couldn’t use respiratory treatment equipment because they didn’t have electricity, and 8.6% couldn’t get medical care because their local medical facilities were closed.

Other problems included doctors leaving and an inability to reach 911. One third of deaths reported by those surveyed were caused by a lack of medical care.

“These numbers will serve as an important independent comparison to official statistics from death-registry data, which are currently being reevaluated, “the authors concluded, “and underscore the inattention of the U.S. government to the frail infrastructure of Puerto Rico.”


"Excess Deaths" in Puerto Rico - Puerto Rico Report

[…] Later estimates extrapolated from data collected by interviewers. Harvard researchers included deaths caused by a lack of medical care following the hurricane, including those individuals who needed treatment that required electricity and were not able to get it. They also included deaths from contaminated water, since the hurricane made drinkable water scarce in many areas. The possible total estimated by this means ranged from 793 to 8498. While the researchers set their estimate in the middle of the range, at nearly 5,000, this number is widely considered too large and too uncertain. […]

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