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New study sheds light on death toll from Hurricane Maria in Puerto Rico

The official government count of the number of people killed when Hurricane Maria pummeled Puerto Rico last year stands at 64. But researchers say the true number of deaths may actually be much higher. A new analysis puts the figure at 1,139. While that's many times the official figure, it is not as high as another study that came out earlier this year.

The researchers used official government death records in their study, according to a paper on the findings published Thursday in the Journal of the American Medical Association, a peer-reviewed medical journal. The findings took into account people who died from both the hurricane's immediate impact and its secondary effects during the months after it barreled into Puerto Rico in September.

"If we have a better idea of the damage that Hurricane Maria actually did, then maybe we can use that experience to inform and reshape protocols, policies and emergency management protocols," Alexis Raúl Santos, an assistant professor of human development and family studies at Penn State, said in a news release on the findings. 

The news release says this study is different from other estimates that used data from surveys or government agencies, "which may not be reliable." A Harvard University study released in May said the hurricane was likely responsible for more than 4,600 deaths, a figure that was based on results of a door-to-door survey of 3,299 randomly selected homes across the island.

The new study points out that the official death toll only counts people who have a "hurricane-related" cause of death on their death certificate, and does not account for "indirect deaths," such as people who died from infectious disease outbreaks, lack of access to medical care, or outages of water and electricity.

To arrive at their estimate, the researchers looked at official government death records to determine how many people died from any cause between January 2010 through December of last year in Puerto Rico. Figures from before Maria hit were then used to determine "the average expected deaths for each month." When that data was compared to the number of people who died from late September through December 2017 — the months after Maria hit — researchers found that about 1,139 more people died than would have been expected in that time period.

The researchers called their estimate of 1,139 deaths conservative.

The study notes, however, that its primary limitation "is that the specific cause of each individual death is not known; thus only an aggregate number of deaths in excess of historical variation can be estimated."