President Donald Trump’s campaign rallies have reportedly resulted in 30,000 COVID-19 cases that caused more than 700 deaths, according to a new study from Stanford University.

The article, titled “The Effects of Large Group Meetings on the Spread of COVID-19: The Case of Trump Rallies,” was released on Friday and examines 18 Trump rallies across the country that were held between June 20 and Sept. 22. While the Republican presidential ticket has held rallies since, the study excludes them from the analysis to allow at least four weeks of post-event data in order to track incremental infections over time.

“At least through September 2020, the degree of compliance with guidelines concerning the use of masks and social distancing was low, in part because the Trump campaign downplayed the risk of infection. This feature heightens the risk that a rally could become a ‘superspreader event,’” the study reads.

The authors, B. Douglas Bernheim, Nina Buchmann, Zach Freitas-Groff and Sebastián Otero, also note that compliance with precautions have improved in recent events and that they lack sufficient data to study its relationship to coronavirus outbreaks.

The study estimates that Trump’s campaign rallies increased subsequent coronavirus cases by more than 250 per 100,000 residents. The estimated 700 deaths are not limited to those who attended the event, because rally-goers who became COVID-19 positive could have spread the virus to a friend or family who died from it, the article states.

The writers, furthermore, take a closer look at two counties – Marathon County in Wisconsin and Winnebago County in Illinois — that were “highly impacted” by Trump rallies, according to their analysis. While testing did not immediately rise in both counties, Marathon county saw an increase in positive cases following the rally that continued to climb sharply for weeks. Meanwhile, Winnebago county’s rates doubled over the first four weeks and continued to increase.

These findings align with the study’s hypothesis, refuting that the increase in testing resulted in greater detection of positive cases that would have occurred without the rally.

In identifying coronavirus outbreaks tied to Trump campaign rallies, the researchers pulled data from the COVID-19 Data Repository maintained by the Center for Systems Science and Engineering at Johns Hopkins University. Information on COVID-related policies and country-level demographic and election data were obtained from the state departments of public health.

The article’s conclusion reiterates that its data analysis “strongly supports the warnings and recommendations of public health officials concerning the risk of COVID-19 transmission at large group gatherings,” especially when compliance with precautions is low. As the study states, “The communities in which Trump rallies took place paid a high price in terms of disease and death.”