Researchers at the Pereleman School of Medicine, University of Pennsylvania, in the United States, tested the effectiveness of the drug – which has been advocated, among others, by Jair Bolsonaro – in health workers, one of the groups with great potential for contagion.
The conclusion was that the rates of infection with the new coronavirus were the same among those taking hydroxychloroquine and placebo.
It was also observed that contagion levels were low among participants, which the researchers attributed to the effectiveness of other preventive measures, such as social distance, the use of personal equipment and correct hand hygiene.
“This work is the first randomized test of the prophylactic effect of hydroxychloroquine,” explained the researcher and lead author of the study, Benjamin Abella.
“Although hydroxychloroquine is effective in treating diseases like lupus and malaria, we saw no difference that led us to recommend its prescription as a preventive drug for Covid-19 to frontline workers,” he added.
Altogether, a group of 125 doctors, nurses, assistants, technicians, among others, took a daily dose of 600 milligrams of hydroxychloroquine, over two months, to verify the effectiveness in preventing infection with the new coronavirus.
Between April 9 and July 14, half of those tested took the drug, while the other unknowingly received an equivalent placebo (a cellulose pill).
The participants also underwent electrocardiograms, given the possibility that hydroxychloroquine could cause problems in the heart rhythm of patients due to Covid-19 in serious condition.
At the end of the study, 6.3% of participants who took the drug were infected with the new coronavirus. Among those who took placebo, 6.6% were infected with the pathogen.
In addition, no differentiation in the heart rate of the volunteers was detected, which indicated that hydroxychloroquine, in addition to not having a preventive effect, is also not harmful, although it causes side effects, such as diarrhea.
“The differences we saw were insignificant. And those who contracted the virus, whether or not they were taking hydroxychloroquine, were all asymptomatic or had very mild symptoms,” said Ravi Amaravadi, a researcher at the Abramson Cancer Center and co-author of the study.