Two scientific journals on Thursday retracted studies examining potential treatments for Covid-19, including one study that linked the anti-malaria drug hydroxychloroquine to a higher risk of death in Covid-19 patients, after researchers raised concerns over the data used for the studies.

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US rate of reported new coronavirus infections has ticked up since Memorial Day

The news comes as U.S. officials as of Friday morning reported 1,883,000 cases of Covid-19, the disease caused by the new coronavirus—up from 1,861,200 cases as of Thursday morning.

According to a CNBC analysis of Covid-19 data gathered by Johns Hopkins University, the average weekly rate of newly reported cases of new coronavirus infections in the United States has been rising slowly since Memorial Day. CNBC found that the weekly rate of newly reported infections in the country had reached a peak on April 10, at an average of 31,578 cases, before falling to an average of 20,600 newly reported infections on May 28. However, as of Wednesday, the weekly rate of newly reported infections from the new coronavirus has increased to an average of 21,763.

Experts say the growth rate of newly reported infections in the United States may be accelerating because, over the past few weeks, many states have reopened nonessential businesses and loosened social distancing measures intended to slow the new coronavirus' spread.

Jill Roberts of the University of South Florida College of Public Health, told Politico, "The cases today represent what occurred about two weeks ago. Memorial Day weekend is likely to blame for the increase in cases, both due to relaxation of social distancing measures and the holiday resulting in more people moving about."

However, officials have noted that, in some states, the increases in the rates of newly reported coronavirus infections could be tied to more robust testing for the virus.

As of Friday morning, officials had reported a total of 108,194 U.S. deaths linked to the new coronavirus—up from 107,171 deaths reported as of Thursday morning.

Scientific journals retract two studies on potential Covid-19 treatments

As the numbers of reported cases of new coronavirus infections and related deaths continue to rise throughout America, public health officials and researchers have been scrambling to develop a vaccine against the virus and find potential treatments for Covid-19.

One experimental treatment that researchers have been evaluating is the anti-malaria drug hydroxychloroquine. President Trump has widely touted the drug as a potential treatment for Covid-19, but health experts have noted that hydroxychloroquine hasn't been approved to treat the disease. In addition, experts have said the drug can cause patients to experience severe side effects, including serious heart rhythm problems.

Further, a study published last month in The Lancet found that hydroxychloroquine was linked with an increased risk of death among Covid-19 patients. But a few days after the study was published, more than 180 scientists and physicians from around the world called out inconsistencies in the data used for the study, as well as concerns over the method the researchers used to analyze the data.

The concerns prompted The Lancet on Friday to post a correction stating that the study had incorrectly reported the number of patients included in the study from Asia and Australia. In the correction, the research team behind the study updated the data from Australia and Asia and an appendix they had included in the study. The researchers said the data discrepancy did not affect the study's findings.

But Richard Horton, the editor of The Lancet, on Tuesday voiced concerns about the study's findings, as well. Horton in a tweet wrote, "Serious questions have been raised about the reliability of the findings reported in this paper."

Separately, Eric Rubin, the editor of the New England Journal of Medicine (NEJM), in an editorial published Tuesday expressed concerns over a different study that NEJM had published last month that found certain cardiovascular and blood-pressure drugs were safe to use in patients with Covid-19. That study involved the same data, which was compiled by Surgisphere, that was called into questions in the study published in The Lancet. Both studies also involved three of the same researchers. Rubin in the editorial wrote that "[s]ubstantive concerns ha[d] been raised about the quality of the information in [Surgisphere's] database," and NEJM "asked the authors to provide evidence that the data are reliable."

On Thursday, the researchers involved in the studies, along with the The Lancet and NEJM, retracted the studies. The researchers said they decided to retract the studies because they could not verify the data used to produce the studies' findings, in part because Surgisphere declined to share additional details on the data. Mandeep Mehra of Brigham and Women's Hospital and Harvard Medical School, who was the lead author of the studies, in a statement said, "It is now clear to me that in my hope to contribute to this research during a time of great need, I did not do enough to ensure that the data source was appropriate for this use." Mehra added, "Since we do not have the ability to verify the primary data or primary data source, I no longer have confidence in the origination and veracity of the data, nor the findings they have led to."

A spokesperson for Surgisphere has said the company cannot release details identifying the hospitals that reported the data used for the studies because of privacy agreements (Lovelace/Rattner, CNBC, 6/4; Canipe/Shumaker, Reuters, 6/2; Dixon, Politico, 6/4; Owens, "Vitals," Axios, 6/4; Hopkins/Gold, Wall Street Journal, 6/4; Rabin/Gabler, New York Times, 6/4; McGinley, Washington Post, 6/4; Herper/Joseph, STAT News, 6/2; Marchione, Associated Press, 6/2; Lancet retraction notice, 6/4; New York Times, 6/5).