Treatment with the antiparasitic drug ivermectin could help reduce viral load and speed up recovery in patients with mild-to-moderate COVID-19, suggest results from a Spanish study.
The small pilot study was led by the University of Navarra Clinic and the Barcelona Institute for Global Health and sought to test whether claims about benefits of ivermectin for treating SARS-CoV-2 were scientifically valid.
While this study requires validation in a bigger patient group, the initial results suggest that one dose of ivermectin given to mild COVID-19 patients reduced viral load and the duration of symptoms such as cough and loss of smell and taste.
Although vaccines are now being rolled out to combat SARS-CoV-2 infection, the virus is now so widespread that it will take time for these interventions to have a significant impact. Effective treatments that can help reduce spread or help those infected get back to their normal lives more quickly are needed.
Ivermectin is widely used around the world to treat parasitic infections caused by worms, headlice, and other organisms. It is an effective antiparasitic treatment, but can cause side effects such as fever, itching, and skin rash, particularly at higher doses.
Largely unvalidated claims early in the pandemic led to it being widely used in those infected with SARS-CoV-2 in South America. Ivermectin is known to reduce replication of the virus at relatively high doses in the lab, but while there are now a number of ongoing studies testing the drug in COVID-19 patients, there is still a lack of properly conducted randomized controlled trial data for clinicians to refer to.
With this in mind, Carlos Chaccour, M.D., Ph.D., a researcher at ISGlobal and physician at the University of Navarra Clinic, and colleagues decided to carry out a randomized controlled pilot trial to assess the efficacy of ivermectin in mild COVID-19 patients.
Overall, 24 people were recruited to take part in the trial after reporting to the Clínica Universidad de Navarra with symptoms of fever or cough, who subsequently had a confirmed diagnosis of mild COVID-19, between July 31, 2020 and September 11, 2020. The results of the trial are described in the journal EClinicalMedicine.
Patients were randomly assigned to receive 400 mcg/kg ivermectin or placebo. The primary outcome measure of the trial was assessment of whether SARS-CoV-2 infection was still detectable 7 days after treatment with ivermectin. Patient recovery was also followed up in both groups to assess the impact of treatment on symptoms.
While treatment with ivermectin did not impact viral load enough for there to be a significant difference between the placebo and treatment groups at 7 days, there was a noticeable reduction in viral load in the treatment group versus the placebo group at days 4 and 7 after treatment by around three and 18 times, respectively.
IgG antibody titers were also lower in the treatment group at 21 days versus the placebo group. “This could be the result of a lower viral load in these patients,” explains Chaccour.
Patients in the treatment group also seemed to recover about 30% more quickly from cough and 50% more quickly from loss of smell or taste than those given placebo.
“Our findings are in line with those from recent assays conducted in Bangladesh and Argentina,” says Chaccour. “Although our study is small and it is too early to draw conclusions, the trends observed in viral loads, symptom duration and antibody levels are encouraging and warrant further exploration in larger clinical trials with a higher diversity of patients.”
The team are not certain of the mode of action of ivermectin, but think it interferes with the way the virus enters into cells and reduces viral load in that way rather than having an anti-inflammatory impact on the immune system.