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Preliminary meta-analysis of randomized trials of ivermectin to treat SARS-
CoV-2 infection
Authors: Andrew Hill on behalf of the International Ivermectin Project Team*
International Ivermectin Project Team
Ahmed S. Abdulamir1, Sabeena Ahmed2, Asma Asghar3, Olufemi Emmanuel
Babalola4, Rabia Basri5, , Aijaz Zeeshan Khan Chachar5, Abu Taiub Mohammed
Mohiuddin Chowdhury7, Ahmed Elgazzar8, Leah Ellis9, Jonathan Falconer10, Anna
Garratt11, Basma M Hany8, Hashim A. Hashim12, Wasim Md Mohosin Ul Haque13,
Arshad Hayat3, Shuixiang He7, Ramin Jamshidian14, Wasif Ali Khan2, Ravi Kirti15,
Alejandro Krolewiecki16, Carlos Lanusse17, Jacob Levi18, Reaz Mahmud19, Sermand
Ahmed Mangat3, Kaitlyn McCann9, Anant Mohan20, Morteza Shakhsi Niaee21,
Nurullah Okumuş22, Victoria Pilkington23, Chinmay Saha Podder24, Ambar Qavi9,
Houssam Raad25, Ali Samaha25, Hussein Mouawia25, Mohammad Sadegh Rezai26,
Surapaneni Sasank27, Veerapaneni Spoorthi28, Tejas Suri20, Junzheng Wang9,
Hannah Wentzel9 , Andrew Hill29
1. College of Medicine, Alnahrain University, Alkadymia, Baghdad, Iraq
2. International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
3. Department of Medicine, Combined Military Hospital, Lahore, Pakistan
4. Bingham University/Lagos University, Nigeria
5. Fatima Memorial Hospital, Lahore, Pakistan
6. Barcelona Institute for Global Health, Clinica Universidad de Navarra,
Universidad de Navarra, Spain
7. Xi'an Jiaotong University Medical College First Affiliated Hospital, Shaanxi,
8. Faculty of Medicine, Benha University, Banha, Egypt
9. Faculty of Medicine, Imperial College London, UK
10. Department of Infectious Diseases, Chelsea and Westminster Hospital,
Imperial NHS Trust, London, UK
11. Department of Infectious Diseases, University Hospital of Wales, Cardiff and
Vale University Health Board, UK
12. Alkarkh Hospital, Alatefiya, Baghdad, Iraq
13. Department of Nephrology, BIRDEM General Hospital, Dhaka, Bangladesh
14. Jundishapur University of Medical Sciences, Ahvaz, Iran
15. Department of General Medicine, All India Institute of Medical Sciences,
Patna, India
16. Instituto de Investigaciones de Enfermedades Tropicales (IIET-CONICET),
Sede Regional Orán, Universidad Nacional de Salta, Argentina
17. Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil
(CIVETAN), CONICET-CICPBA-UNCPBA, Facultad de Ciencias Veterinarias,
Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil,
18. Department of Intensive Care, University College London Hospital, ULCH
NHS Trust, London, UK
19. Department of Neurology, Dhaka Medical College, Dhaka, Bangladesh
20. Department of Pulmonary Critical Care & Sleep Medicine, All India Institute of
Medical Sciences, New Delhi, India
21. Qazvin Science & Technology Park, Qazvin, Iran
22. Department of Neonatology, Afyonkarahisar Health Sciences University,
Afyonkarahisar, Turkey
23. Oxford University Clinical Academic Graduate School, University of Oxford, UK
24. Debidwar Upazila Health Complex, Debidwar, Comilla, Bangladesh
25. Biotherapies de Maldies Genetiques et Cancer, Universite Bordeaux Segalen,
Bordeaux, France
26. Pediatric Infectious Diseases Research Center, Communicable Diseases
Institute, Mazandaran University of Medical Sciences, Sari, Iran
27. Gandhi Hospital, Andhra Pradesh, India
28. Apollo Medical College, Hyderabad, India
29. Department of Pharmacology and Therapeutics, University of Liverpool,
Liverpool, L7 3NY, UK
Funding: Unitaid
Conflicts of Interest: None of the authors has declared a conflict of interest
Corresponding author:
Dr Andrew Hill PhD
Department of Pharmacology and Therapeutics
University of Liverpool,
70 Pembroke Place
Liverpool L69 3GF, UK
Introduction: Ivermectin is a well-established antiparasitic drug licensed since 1981,
more recently approved for its anti-inflammatory effects against rosacea. It is being
investigated for repurposing against SARS-CoV-2. In-vitro, ivermectin showed some
antiviral activity but at higher concentrations than achieved in human plasma after
normal oral dosing. An animal model demonstrated pathological benefits in COVID-
19 but no effect on viral RNA. We aimed to assess the available global data from
randomized controlled trials (RCTs) of ivermectin in COVID-19.
Methods: We conducted a systematic search of PUBMED, EMBASE, MedRxiv and
trial registries. We excluded prevention studies and non-randomized or case-
controlled studies. We identified and included 18 RCTs. Data were combined from
2282 patients into a systematic review and meta-analysis.
Results: Ivermectin was associated with reduced inflammatory markers (C-Reactive
Protein, d-dimer and ferritin) and faster viral clearance by PCR. Viral clearance was
treatment dose- and duration-dependent. Ivermectin showed significantly shorter
duration of hospitalization compared to control. In six RCTs of moderate or severe
infection, there was a 75% reduction in mortality (Relative Risk=0.25 [95%CI 0.12-
0.52]; p=0.0002); 14/650 (2.1%) deaths on ivermectin; 57/597 (9.5%) deaths in
controls) with favorable clinical recovery and reduced hospitalization.
Discussion: Many studies that were included were not yet published or peer-
reviewed and meta-analyses are prone to confounding issues. Furthermore, there
was a wide variation in standards of care across trials, and ivermectin dose and
duration of treatment was heterogeneous. Ivermectin should be validated in larger,
appropriately controlled randomized trials before the results are sufficient for review
by regulatory authorities.
Keywords: SARS-CoV2, COVID-19, Ivermectin, repurposed
The pandemic of SARS-CoV-2 continues to grow, with 650,000 new infections and
over 11,000 deaths recorded worldwide daily in January 2021 [1]. Protective
vaccines have been developed, but current supplies are too low to cover worldwide
demand in the coming months [2]. Researchers worldwide are urgently looking for
interventions to prevent new infections, or prevent disease progression, and lessen
disease severity for those already infected.
While research on new therapeutic agents for COVID-19 is key, there is also great
interest on evaluating the potential use against COVID-19 of already existing
medicines, and many clinical trials are in progress to ‘re-purpose’ drugs normally
indicated for other diseases. The known safety profiles, shortened development
timelines, and well-established markets (with low price points and higher capacity to
deliver at scale) for most of already existing compounds proposed for COVID-19 are
particularly advantageous compared to new drug discovery in a pandemic situation.
Three re-purposed anti-inflammatory drugs have shown significant survival benefits
to date: the corticosteroid dexamethasone in the UK RECOVERY trial [3], and the
Interleukin-6 (IL-6) receptor antagonist drugs, tocilizumab and sarilumab, in the
REMAP-CAP trial [4]. Other re-purposed antimicrobials such as,
hydroxychloroquine, lopinavir/ritonavir, remdesivir and interferon-beta, have shown
no significant survival benefit in two large, randomized trials [3, 5] despite initial
reports of efficacy, underscoring the need for caution when interpreting early clinical
trial data.
Dexamethasone is recommended for use by the WHO and has proven survival
benefits for oxygen-dependent patients with COVID-19, while tocilizumab and
sarilumab improves survival for patients in intensive care [3, 4]. However, there are
no approved treatments for patients with mild SARS-CoV-2 infection, either to
prevent disease progression or reduce viral transmission. Treatments increasing
viral clearance rate, may lower risk of onward transmission but this requires
empirical demonstration.
Ivermectin is a well-established anti-parasitic drug used worldwide for a broad
number of parasites and also for topical use against rosacea. Antiviral activity of
ivermectin has been demonstrated for SARS-CoV-2 in Vero/hSLAM cells [IB6].
However, concentrations required to inhibit viral replication in vitro (EC50=2.8M;
EC90=4.4M) are not achieved systemically after oral administration of the drug to
humans [6, 7]. The drug is estimated to accumulate in lung tissues (2.67 times that
of plasma) [8], but this is also unlikely to be sufficient to maintain target
concentrations for pulmonary antiviral activity [7, 9]. Current data suggest that the
dosages of ivermectin used in human trials are unlikely to provide systemic or
pulmonary concentrations necessary to exert meaningful direct antiviral activity.
Notwithstanding, ivermectin is usually present as a mixture of two agents and
although mainly excreted unchanged in humans, has two major metabolites [10].
Current data are insufficient to determine whether the minor form or a circulating
metabolite has higher direct potency against SARS-CoV-2, but it seems likely that it
would need to be profoundly more potent than the reported values.
Ivermectin has also demonstrated immunomodulatory and anti-inflammatory
mechanisms of action in preclinical models of several other indications. In-vitro
studies have demonstrated that ivermectin suppresses production of the
inflammatory mediators nitric oxide and prostaglandin E2 [11]. Furthermore,
avermectin (from which ivermectin is derived) significantly impairs pro-inflammatory
cytokine secretion (IL- and TNF-α) and increases secretion of the
immunoregulatory cytokine IL-10 [12]. Ivermectin also reduced TNF-α, IL-1, and IL-6,
and improved survival in mice given a lethal dose of lipopolysaccharide [13].
Preclinical evidence to support these immunomodulatory and anti-inflammatory
mechanisms of action have also been generated in murine models of atopic
dermatitis and allergic asthma [14, 15]. Finally, in Syrian golden hamsters infected
with SARS-CoV-2, subcutaneous ivermectin demonstrated a reduction in the IL-6/IL-
10 ratio in lung tissues and prevented pathological deterioration [16]. The impact of
ivermectin in this model appeared to be gender specific, appearing more active in
females than in males. Irrespective of gender, no impact of ivermectin on viral titers
in lung or nasal turbinate was observed in this model, supporting a mechanism of
action not relating to direct antiviral activity.
In pharmacokinetic studies, the Area Under the Curve (AUC) and maximum
concentration (Cmax) of ivermectin are generally dose proportional, and
bioavailability of ivermectin increases 2.57-fold in the fed state [8]. Increasing the
frequency or dose of ivermectin does increase the Cmax and AUC of total drug, but
not sufficiently to reach the published EC50 against SARS-CoV-2 in monkey
Vero/hSLAM cells [8]. Ivermectin has approximately twice the systemic availability
when given as an oral solution compared to solid forms (tablets or capsules) [10].
At standard doses, of 0.2-0.4mg/kg for 1-2 days, ivermectin has a good safety profile
and has been distributed to billions of patients worldwide in mass drug administration
programs. A recent meta-analysis found no significant difference in adverse events
in those given higher doses of ivermectin, of up to 2mg/kg, and those receiving
longer courses, of up to 4 days, compared to those receiving standard doses [17].
Ivermectin is not licensed for pregnant or breast-feeding women, or children <15kg.
The objective of this systematic review and meta-analysis was to combine available
results from published or unpublished randomized trials of ivermectin in SARS-CoV-
2 infection.Limitations of current analysis is important as it is being performed with
secondary data from a wide variety of different trials in many different parts of the
world with designs that were not originally meant to be compatible. Further refined
analysis, including direct data examination, are warranted.
The systematic review and meta-analysis was conducted according to PRISMA
guidelines. A systematic search of PUBMED and EMBASE was conducted to
identify randomized control trials (RCT) evaluating treatment with ivermectin for
SARS-CoV-2 infected patients. Clinical trials with no control arm, or those
evaluating prevention of infection were excluded alongside non-randomized trials
and case-control studies. Key data extracted included baseline characteristics (age,
sex, weight, oxygen saturation, stage of infection), changes in inflammatory markers,
viral suppression after treatment, clinical recovery, hospitalization and survival. Data
were extracted and cross-checked by two independent reviewers (HW and LE).
Search strategy and selection criteria
RCTs were eligible for inclusion if they compared an ivermectin-based regimen with
a comparator or standard of care (SOC) for the treatment of COVID-
19. [18] was searched on 14th December 2020 using key words
COVID, SARS-CoV-2 and ivermectin to identify studies. The WHO International
Clinical Trials Registry Platform (ICTRP) was accessed via the COVID-NMA
Initiative’s mapping tool, updated to 9th December 2020, [19] and Stamford
University’s Coronavirus Antiviral Research Database (CoV-RDB), updated to 15th
December 2020, [20] to identify additional trials listed on other national, and
international registries.
Additionally, literature searches via PubMed, and the preprint server MedRxiv were
conducted to identify published studies not prospectively or retrospectively registered
in a trial registry. Duplicate registrations, non-controlled studies and prevention
studies were excluded following discussion between the authors.
In a third stage of data collection, the research teams conducting unpublished clinical
trials were contacted and requested to join regular international team meetings in
December 2020 and January 2021. All results available from unpublished studies
were also included in this systematic review.
All of the clinical trials included in this meta-analysis were approved by local ethics
committees and all patients signed informed consent.
The primary outcome was all-cause mortality from randomization to the end of
follow-up. Changes in inflammatory markers, viral suppression, clinical recovery and
hospitalization were measured in different ways between trials and were summarized
for individual clinical trials where endpoints could not be combined.
Data analysis
Statistical analyses for all-cause mortality were conducted with summary published
data, on the intention-to-treat population, including all randomized patients. Clinical
trials with at least two deaths reported were included in this analysis. Treatment
effects were expressed as risk ratios (RR) for binary outcomes. For each outcome
we pooled the individual trial statistics using the random-effects inverse-variance
model; a continuity correction of 0.5 was applied to treatment arms with no deaths.
Heterogeneity was evaluated by I2. The significance threshold was set at 5% (two-
sided) and all analyses were conducted using Revman 5.3.
All studies included in this analysis were assessed for risk of bias using the
Cochrane Collaboration risk of bias standardized assessment tool [21] and the
outcome of this assessment is given in supplementary table 1.
In this meta-analysis, 18 RCTs involving a total of 2282 participants were included.
The sample sizes of each trial ranged from 24 to 400 participants. Of the 18 included
studies, five were published papers, six were available as pre-prints, six were
unpublished results shared for this analysis; one reported results via a trial registry
Overall, nine trials investigated ivermectin as a single dose (Table 1A), nine trials
investigated multi-day dosing up to seven days (Table 1B), of which three trials were
dose-ranging. In this meta-analysis, ivermectin was largely investigated in
mild/moderate participants (11 trials). Overall, 12 trials were either single or double-
blinded and six were open-label.
Effects on Inflammatory Markers
Five trials provided results of the effect of ivermectin on inflammatory markers
including C-reactive protein (CRP), ferritin and d-dimer (Table 2). Four of these trials
demonstrated significant reductions in CRP compared to control. Furthermore, in the
Elgazzar trial [22], ivermectin significantly reduced ferritin levels compared to control
in the severe patient population while no significant difference was demonstrated in
the mild/moderate population. The Okumus trial [23] showed significantly greater
reductions in in ferritin on day 10 of follow-up for ivermectin versus control. The
Chaccour [24] and Ahmed [25] trials showed no significant difference in ferritin count
between ivermectin and control. Elgazzar [22] showed significant differences in d-
dimer between ivermectin and control in both the mild/moderate and severe
populations. Okumus [23] showed significant differences in d-dimer on day 5 whilst
Chaccour [24] found no differences between ivermectin and control, but with a
smaller sample size.
Effects on Viral Clearance
Three different endpoints were used to analyze viral clearance: the percentage of
patients undetectable on a set day (Table 3A), the number of days from
randomization to negativity (Table 3B), and other measures such as cycle time (Ct)
values and dose-response correlations (Table 3C). The Kirti [26] and Okumus [23]
trials included viral load analysis only in a subset of patients. The effects of
ivermectin on viral clearance were generally smaller when dosed on only one day.
Several studies showed no statistically significant effect of ivermectin on viral
clearance [27, 28, 29].
The three studies randomizing patients to different doses or durations of ivermectin
showed apparent dose-dependent effects on viral clearance. Firstly, in the Babalola
trial [30], the 0.4mg/kg dose showed trends for faster viral clearance than the
0.2mg/kg dose. Secondly, in the Mohan trial [28], the 0.4 mg/kg dose of ivermectin
led to a numerically higher percentage of patients with viral clearance by day five
than the 0.2mg/kg dose. Thirdly, in the Ahmed trial [25], ivermectin treatment for five
days led to a higher percentage of patients with viral clearance at day 13 compared
with one day of treatment. Finally, in Krolewiecki [31], PK/PD correlations showed
significantly faster viral clearance for patients with PK exposures above 160ng/mL.
The effect of ivermectin on viral clearance was most pronounced in the randomized
trials evaluating doses of up to five days of ivermectin treatment, using doses of
0.4mg/kg (Figure 1). At these doses, there were statistically significant effects on
viral clearance in all four randomized trials.
Effects on Clinical Recovery and Duration of Hospitalization
Definitions of clinical recovery varied across trials, as shown in Table 4. In Table 4A,
four of the six trials showed significantly faster time to clinical recovery on ivermectin
compared to control. In five trials, ivermectin showed significantly shorter duration of
hospitalization compared to control (Table 4B).
Effects on Survival
Six randomized trials reported that at least two people had died post-randomization
and were included in the analysis (Table 5). Across these six trials in 1255 patients,
there were 14/658 (2.1%) deaths in the ivermectin arms, versus 57/597 (9.5%)
deaths in the control arms. In a combined analysis using inverse variance weighting
ivermectin showed a 75% improvement in survival (RR 0.25 [95%CI 0.12-0.52];
p=0.0002, Figure 2). Heterogeneity was moderate, I2 = 34%.
Evaluation of Studies.
An evaluation of the quality of the studies included in this meta-analysis was
conducted according to the Cochrane Collaboration tool to assess the risk of bias. Of
the 18 trials, 11 were of poor quality and seven of fair or high quality. Further
evaluation with access to original data from the trials is warranted to increase quality
of evidence. [Supplementary table 1]
This systematic review of 18 RCTs (n = 2282) showed ivermectin treatment reduces
inflammatory markers, achieves viral clearance more quickly and improves survival
compared with SOC. The effects of ivermectin on viral clearance were stronger for
higher doses and longer durations of treatment. These effects were seen across a
wide range of RCTs conducted in several different countries. However, the data
should be interpreted carefully in the context that meta-analyses are highly prone to
confounding bias, and current viral PCR assays have several important limitations.
Many of the studies assessed have not been peer-reviewed. Larger, appropriately
controlled randomized trials are needed before rigorous evaluation of the clinical
benefits of ivermectin can be undertaken.
The results from this analysis have emerged from the International Ivermectin
Project Team meetings in December 2020 and January 2021. Independent research
teams were conducting the trials across 12 countries and agreed to share their data,
which was often unpublished, to accelerate the speed of reporting and to ensure
their fragmented research, widespread across the world, could contribute to global
learning. Viral clearance was evaluated by Polymerase Chain Reaction (PCR)
assays in all the studies. We have only included randomized clinical trials in this
meta-analysis. The 18 RCTs included were designed and conducted independently,
with results combined in December 2020.
Key limitations to this meta-analysis include the comparability of the data, with
studies differing in dosage, treatment duration, and inclusion criteria. Furthermore,
the SOC used in the background treatment differed between different
trials. Additionally, ivermectin was often given in combination with doxycycline or
other antimicrobials. Individual trials may not have power to detect treatment effects
on rare endpoints such as survival. Outcome measures were not standardized; viral
clearance was measured in most trials, but at different time points and with different
PCR cycle thresholds. The reliability of PCR tests for quantification purposes has
been the subject of substantive debate. Most studies were conducted in populations
with only mild/moderate infection and some trials excluded patients with multiple co-
For open label studies, there is a risk of bias in the evaluation of subjective endpoints
such as clinical recovery and hospital discharge. However, the risk is lower for
objective endpoints such as viral clearance and survival. We have attempted to
control for publication bias by contacting each research team conducting the trials
directly. This has generated more results than would be apparent from a survey of
published clinical trials only but means that many of the included trials have not been
peer-reviewed. Review and publication of RCTs generally takes three to six months.
It has become common practice for clinical trials of key COVID-19 treatments to be
evaluated from pre-prints, such as for the WHO SOLIDARITY, RECOVERY and
REMAP-CAP trials [3, 4, 5].
These RCTs have been conducted in a wide range of countries, often in low-
resource conditions and overburdened healthcare systems. The evidence from this
first set of studies will require validation in larger RCTs evaluating fixed dosing
schedules, preferably using higher doses for between 3-5 days. Larger RCTs are
currently underway in Mexico, South America and Egypt, with results expected in
February and March 2021.
Despite limitations, this analysis suggests a dose and duration-dependent impact of
ivermectin on rate of viral clearance. These trials evaluated a wide range of
ivermectin dosing, from 0.2mg/kg for 1 day to 0.6mg/kg for 5 days. This wide range
of doses allowed an estimation of dose-dependency on viral clearance but reduces
the number of patients included that were consistently administered the same dose
for the same duration. The maximum effective dose of ivermectin is not yet clear and
new clinical trials are evaluating higher doses, up to 1.2mg/kg for 5 days.
The 75% survival benefit seen in this meta-analysis is based only on 71 deaths, in
six different clinical trials. This is a smaller total number of deaths than in either the
RECOVERY or REMAP-CAP trials, which led to the approval of dexamethasone,
tocilizumab and sarilumab. However, the observed survival benefit of 75% is
stronger than for the other re-purposed drugs. Emerging mortality results from larger
studies of ivermectin will require careful evaluation and may change the conclusions
from the current analysis.
Secondary endpoints for some RCTs included biomarkers of disease severity. Some
of these provide evidence for an anti-inflammatory mechanism of action of ivermectin
in SARS-CoV-2 infected patients. Previous meta-analyses have demonstrated that
high levels of CRP, ferritin, d-dimer and lymphocytopenia are related to COVID-19
severity and hyper-inflammation [32, 33]. Studies of IL-6 receptor antagonists have
been shown to reduce CRP and d-dimer levels in patients with COVID-19 [4].
Across three studies, in a cumulative 683 patients, we found a slight increase in
lymphocyte counts [22, 34, 35] following ivermectin administration. CRP, a marker of
infection and inflammation, were reduced following ivermectin administration across
four trials [22, 23, 25, 34]. D-dimer is a fibrin degradation product, often raised in
severe COVID-19 due to thrombus formation. Ferritin can also be raised in severe
COVID-19 due to the cytokine storm and hyperinflammation. Levels of both d-dimer
and ferritin following one week of ivermectin treatment in severe COVID-19 cases
were reduced to levels less than half of those receiving SOC [22]. These reductions
in D-dimer and ferritin were more significant in patients with severe disease
compared to those with mild/moderate disease at baseline. Furthermore, erythrocyte
sedimentation rate and lactate dehydrogenase, non-specific markers of inflammation
and tissue damage, respectively, were both reduced slightly following ivermectin
administration in two separate studies of patients with COVID-19 [34, 36].
A key component of SARS-CoV-2 pathogenesis is its pro-thrombotic effect, leading
to blood clots in the kidneys, brain and pulmonary emboli in the lungs. By reducing
hyper-inflammation, the risk of clots may be reduced. One histopathology study in
dogs with Dirofilaria immitis (heartworm) showed that ivermectin plus doxycycline
reduced lung tissue perivascular inflammation and endothelial proliferation leading to
fewer arterial lesions and virtually removed the risk of thrombi [37]. However, the
relevance of these findings to SARS-CoV-2 infection are unclear.
Ivermectin may also have a role in short-term prevention of SARS-CoV-2 infection,
suggested by pilot studies [38, 39]. This potential benefit also needs to be validated
in larger randomized trials.
At the time of writing, knowledge gaps prevent a robust conclusion about the
mechanism of action, but current in vitro data do not support a direct antiviral activity
of the drug. Interestingly, ivermectin has been demonstrated to induce autophagy as
part of a proposed mechanism of action in cancer [40, 41] with autophagy providing
an innate defense against virus infection [42]. Furthermore, other viruses such as
cytomegalovirus have mechanisms to activate cyclooxygenase 2 and prostaglandin
E2 promoting the inflammatory response, which supports their replication [43] and it
is also possible that a pro-inflammatory phenotype may aid SARS-CoV-2 replication
[44]. However, immunological mechanisms of action are usually highly complex and
require careful empirical evaluation to understand the plausibility, which is currently
absent for ivermectin use in COVID-19.
This meta-analysis of 18 RCTs in 2282 patients showed a 75% improvement in
survival, faster time to clinical recovery and signs of a dose-dependent effect of viral
clearance for patients given ivermectin versus control treatment.
Despite the encouraging trend this existing data base demonstrates, it is not yet a
sufficiently robust evidence base to justify the use or regulatory approval of
ivermectin. However, the current paucity of high-quality evidence only highlights the
clear need for additional, higher-quality and larger-scale clinical trials, warranted to
investigate the use of ivermectin further.
The maximum effective dose of ivermectin needs to be clarified and new clinical
trials should use a consistent multi-day dosing regime, with at least 0.4mg/kg/day.
The appropriate dose and schedule of ivermectin still requires evaluation and the
current randomized clinical trials of ivermectin need to be continued until ready for
rigorous review by regulatory agencies.
We would like to thank all the clinical staff, the research teams and the patients who
participated in these studies.
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List of Tables and figures
Table 1: Trial Summaries
A: Ivermectin trials with Dosing on day 1 only
B: Ivermectin trials with multi-day dosing
Table 2: Changes in Inflammatory Markers
Table 3: Effects of ivermectin on viral clearance
A: Effects of ivermectin on viral clearance (binary)
B: Effects of ivermectin on time to viral clearance
C: Effects of ivermectin on other measures of viral clearance
Table 4: Effects on of ivermectin on clinical recovery and hospitalization
A: Time to clinical recovery
B: Effects of ivermectin on duration of hospitalization
C: Number of Participants with clinical recovery by Day 7 to 10 post-randomization
Table 5: Effects of ivermectin on survival
Figure 1: Time to viral clearance
Figure 2: Forest plot of survival
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Background: There has been a growing interest in ivermectin ever since it was reported to have an in-vitro activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This trial was conducted to test the efficacy of ivermectin in mild and moderate coronavirus disease 19 (COVID-19). Methods: A double blind, parallel, randomised, placebo-controlled trial conducted among adult COVID-19 patients with mild to moderate disease severity on admission in a COVID dedicated tertiary healthcare of eastern India. Enrolment was done between 1st August and 31st October 2020. On day 1 and 2 post enrolment, patients in the intervention arm received ivermectin 12 mg while the patients in the non-interventional arm received placebo tablets. Results: About one-fourth (23.6%) of the patients in the intervention arm and one-third (31.6%) in the placebo arm were tested reverse transcriptase polymerase chain reaction (RTPCR) negative for SARS-CoV-2 on 6th day. Although this difference was found to be statistically insignificant [rate ratio (RR): 0.8; 95% confidence interval (CI): 0.4-1.4; p=0.348]. All patients in the ivermectin group were successfully discharged. In comparison the same for the placebo group was observed to be 93%. This difference was found to be statistically significant (RR: 1.1; 95% CI; 1.0-1.2; p=0.045). Conclusions: Inclusion of ivermectin in treatment regimen of mild to moderate COVID-19 patients could not be said with certainty based on our study results as it had shown only marginal benefit in successful discharge from the hospital with no other observed benefits.
Full-text available
Background: The efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear. Methods: We evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours of commencing organ support in an intensive care unit, were randomized to receive either tocilizumab (8mg/kg) or sarilumab (400mg) or standard care (control). The primary outcome was an ordinal scale combining in-hospital mortality (assigned -1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with pre-defined triggers to declare superiority, efficacy, equivalence or futility. Results: Tocilizumab and sarilumab both met the pre-defined triggers for efficacy. At the time of full analysis 353 patients had been assigned to tocilizumab, 48 to sarilumab and 402 to control. Median organ support-free days were 10 (interquartile range [IQR] -1, 16), 11 (IQR 0, 16) and 0 (IQR -1, 15) for tocilizumab, sarilumab and control, respectively. Relative to control, median adjusted odds ratios were 1.64 (95% credible intervals [CrI] 1.25, 2.14) for tocilizumab and 1.76 (95%CrI 1.17, 2.91) for sarilumab, yielding >99.9% and 99.5% posterior probabilities of superiority compared with control. Hospital mortality was 28.0% (98/350) for tocilizumab, 22.2% (10/45) for sarilumab and 35.8% (142/397) for control. All secondary outcomes and analyses supported efficacy of these IL-6 receptor antagonists. Conclusions: In critically ill patients with Covid-19 receiving organ support in intensive care, treatment with the IL-6 receptor antagonists, tocilizumab and sarilumab, improved outcome, including survival.
Full-text available
Background: It appears that ivermectin can potentially act against COVID-19 infection. Today, it is an urgent need to evaluate the efficacy and safety of ivermectin. The effect of ivermectin therapy on mild to severe COVID-19 patients was investigated. Methods: A 45-days randomized, double-blind, placebo-controlled, multicenter, phase 2 clinical trial was designed at five hospitals. A total number of 180 mild to severe hospitalized patients with confirmed PCR and chest image tests were enrolled. The radiographic findings, hospitalization and low O2 saturation duration, and clinical outcomes such as mortality and variables of blood samples were analyzed using standard statistical analyses in SPSS (V20). Results: Average age of the participants was 56 years (45-67) and 50% were women. The primary and secondary results showed significant changes between day zero and day five of admission (∆ 0/5) in terms of ΔALC5/0, ΔPLT5/0, ΔESR5/0, ΔCRP5/0, duration of low O2 saturation, and duration of hospitalization (CI = 95% ). Risk of mortality was also decreased significantly in the study groups. Conclusion: Ivermectin as an adjunct reduced the rate of mortality, low O2 duration, and duration of hospitalization in adult COVID 19 patients. The improvement of other clinical parameters showed that the ivermectin, with a wide margin of safety, had a high therapeutic effect on COVID-19. Trial Registration: This trial was registered with the Iranian Registry of Clinical Trials website (registration ID IRCT20200408046987N1).
Full-text available
The devastating coronavirus disease 2019 (COVID-19) pandemic, due to SARS-CoV-2, has caused more than 47 million confirmed cases and more than 1.2 million human deaths around the globe ¹ , and most of the severe cases of COVID-19 in humans are associated with neurological symptoms such as anosmia and ageusia, and uncontrolled inflammatory immune response 2–5 . Among therapeutic options 6–8 , the use of the anti-parasitic drug ivermectin (IVM), has been proposed, given its possible anti-SARS-CoV-2 activity ⁹ . Ivermectin is a positive allosteric modulator of the α-7 nicotinic acetylcholine receptor ¹⁰ , which has been suggested to represent a target for the control of Covid-19 infection ¹¹ , with a potential immunomodulatory activity ¹² . We assessed the effects of IVM in SARS-CoV-2-intranasally-inoculated golden Syrian hamsters. Even though ivermectin had no effect on viral load, SARS-Cov-2-associated pathology was greatly attenuated. IVM had a sex-dependent and compartmentalized immunomodulatory effect, preventing clinical deterioration and reducing olfactory deficit in infected animals. Importantly, ivermectin dramatically reduced the Il-6/Il-10 ratio in lung tissue, which likely accounts for the more favorable clinical presentation in treated animals. Our data support IVM as a promising anti-COVID-19 drug candidate.
Full-text available
Highlights • Ivermectin, an FDA-approved anti-parasitic agent, was found to be an inhibitor of SARS-CoV-2 replication in the laboratory. • Ivermectin may be effective for the treatment of early-onset mild Covid-19 in adult patients. Early viral clearance of SARS-CoV-2 was observed in treated patients. J o u r n a l P r e-p r o o f • Remission of fever, cough and sore throat did not differ between those treated with or without ivermectin. No severe adverse event observed with the longer duration of ivermectin use. • Larger trials will be needed to confirm these preliminary findings. Abstract Ivermectin, an FDA-approved anti-parasitic agent, was found in vitro to inhibit SARS-CoV-2 replication. To determine the rapidity of viral clearance and safety of ivermectin among adult SARS-CoV-2 patients we conducted a randomized, double-blind, placebo-controlled trial of oral ivermectin alone (12mg once daily for 5 days) or in combination with doxycycline (12mg ivermectin single dose and 200mg stat doxycycline day-1 followed by 100mg 12hrly for next 4 days) compared with placebo among 72 hospitalized patients in Dhaka, Bangladesh. Clinical symptoms of fever, cough and sore throat were comparable among the three treatment arms. Virological clearance was earlier in the 5-day ivermectin treatment arm versus the placebo group (9.7 days vs. 12.7 days; P =0.02); but not with the ivermectin + doxycycline arm (11.5 days; P=0.27). There were no severe adverse drug events recorded in the study. A 5-day course of ivermectin was found to be safe and effective in treating mild COVID-19 adult patients. Larger trials will be needed to confirm these preliminary findings.
Full-text available
Objectives COVID-19 patients suffer from the lack of curative therapy. Hence, there is an urgent need to try repurposed old drugs on COVID-19. Methods Randomized controlled study on 70 COVID-19 patients (48 mild-moderate, 11 severe, and 11 critical patients) treated with 200ug/kg PO of Ivermectin per day for 2-3 days along with 100mg PO doxycycline twice per day for 5-10 days plus standard therapy; the second arm is 70 COVID-19 patients (48 mild-moderate and 22 severe and zero critical patients) on standard therapy. The time to recovery, the progression of the disease, and the mortality rate were the outcome-assessing parameters. Results among all patients and among severe patients, 3/70 (4.28%) and 1/11 (9%), respectively progressed to a more advanced stage of the disease in the Ivermectin-Doxycycline group versus 7/70 (10%) and 7/22 (31.81%), respectively in the control group (P>0.05). The mortality rate was 0/48 (0%), 0/11 (0%), and 2/11 (18.2%) in mild-moderate, severe, and critical COVID-19 patients, respectively in Ivermectin-Doxycycline group versus 0/48 (0%), and 6/22 (27.27%) in mild-moderate and severe COVID-19 patients, respectively in standard therapy group (p=0.052). Moreover, the mean time to recovery was 6.34, 20.27, and 24.13 days in mild-moderate, severe, and critical COVID-19 patients, respectively in Ivermectin-Doxycycline group versus 13.66 and 24.25 days in mild-moderate and severe COVID-19 patients, respectively in standard therapy group (P<0.01). Conclusions Ivermectin with doxycycline reduced the time to recovery and the percentage of patients who progress to more advanced stage of disease; in addition, Ivermectin with doxycycline reduced mortality rate in severe patients from 22.72% to 0%; however, 18.2% of critically ill patients died with Ivermectin and doxycycline therapy. Taken together, the earlier administered Ivermectin with doxycycline, the higher rate of successful therapy.
Purpose : Given the coronavirus disease-2019 (COVID-19) pandemic, there is a global urgency to discover an effective treatment against this disease. This study aimed to evaluate the effect of the widely used antiparasitic drug ivermectin on COVID-19 patient outcomes. Methods In this randomized double-blind clinical trial, COVID-19 patients admitted to two referral tertiary hospitals of Mazandaran, north of Iran, were randomly divided into two groups of intervention and control. In addition to standard treatment for COVID-19, the intervention group received a single weight-based dose (0.2 mg/kg) of ivermectin. Demographic, clinical, laboratory and imaging data of participants were recorded at baseline. Patients were daily assessed for clinical complaints and disease progression. The primary clinical outcome measures were duration of hospital stay, fever, dyspnea, cough, and overall clinical improvement. Findings : Sixty-nine patients with the mean age of 47.6±22.2 and 45.2±23.1 years participated in intervention and control groups, respectively (p=0.6). Nineteen patients (54%) in the ivermectin group and 18(53%) in control group were male (p=0.9). The mean duration of dyspnea was 2.4±1.7 days in the ivermectin and 3.7±2.1 days in the control group (p=0.02). Also, persistent cough lasted for 3.1±1.9 days in the ivermectin group compared to 4.8±2.0 days in control group (p=0.00). The mean duration of hospital stay was 6.9±3.1 vs 8.3±3.3 days for the ivermectin and control group, respectively (p=0.01). Also, the frequency of lymphopenia decreased to 14.3% in the ivermectin group and did not change in the control group (p=0.00). Implications A single dose of ivermectin was well-tolerated in symptomatic COVID-19 patients and improved important clinical features of COVID-19 patients including dyspnea, cough, and lymphopenia. Further studies with larger sample sizes, different drug dosages, dosing intervals and durations, especially in different stages of the disease, may help understanding ivermectin's potential clinical benefits. Trial registration The current controlled trial was registered in the Iranian Registry of Clinical Trials (code: IRCT20111224008507N3) on 2020-06-27.
There are limited antiviral options for the treatment of patients with coronavirus disease 2019 (COVID-19) that have demonstrated clinical efficacy and none of them is an oral drug. Ivermectin (IVM), a macrocytic lactone with a wide anti-parasitary spectrum, has shown potent in vitro activity against SARS-CoV-2 in cell cultures. Methods: We completed a pilot, randomized, controlled, outcome-assessor blinded clinical trial with the goal of evaluating the antiviral activity of high dose IVM in COVID-19 patients. Eligible patients were adults (aged 18 to 69 years) with mild or moderate RT-PCR confirmed SARS-CoV-2 infection within 5 days of symptoms onset. 45 patients were randomized in a 2:1 ratio to standard of care plus oral IVM at 0·6 mg/kg/day for 5 days versus standard of care. The primary endpoint was viral load reduction in respiratory secretions at day-5. Viral load in respiratory secretions was measured through quantitative RT-PCR. Concentrations of IVM in plasma were measured on multiple treatment days. Findings: The trial run between May 18 and September 29, 2020 with 45 randomized patients (30 in the IVM group and 15 controls). There was no difference in viral load reduction between groups but a significant difference in reduction was found in patients with higher median plasma IVM levels (72% IQR 59 – 77) versus untreated controls (42% IQR 31 – 73) (p=0·004). The mean ivermectin plasma concentration levels also showed a positive correlation with viral decay rate (r:0·47, p=0·02). Adverse events were reported in 5 (33%) patients in the controls and 13 (43%) in the IVM treated group, without a relationship between IVM plasma levels and adverse events. Interpretation: A concentration dependent antiviral activity of oral high dose IVM was identified in this pilot trial at a dosing regimen that was well tolerated. Large trials with clinical endpoints are necessary to determine the clinical utility of IVM in COVID-19.
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), known to be the causative agent of COVID-19, has led to a worldwide pandemic. At presentation, individual clinical laboratory blood values, such as lymphocyte counts or C-reactive protein (CRP) levels, may be abnormal and associated with disease severity. However, combinatorial interpretation of these laboratory blood values, in the context of COVID-19, remains a challenge. Methods: To assess the significance of multiple laboratory blood values in patients with SARS-CoV-2 and develop a COVID-19 predictive equation, we conducted a literature search using PubMed to seek articles that included defined laboratory data points along with clinical disease progression. We identified 9846 papers, selecting primary studies with at least 20 patients for univariate analysis to identify clinical variables predicting nonsevere and severe COVID-19 cases. Multiple regression analysis was performed on a training set of patient studies to generate severity predictor equations, and subsequently tested on a validation cohort of 151 patients who had a median duration of observation of 14 days. Results: Two COVID-19 predictive equations were generated: one using four variables (CRP, D-dimer levels, lymphocyte count, and neutrophil count), and another using three variables (CRP, lymphocyte count, and neutrophil count). In adult and pediatric populations, the predictive equations exhibited high specificity, sensitivity, positive predictive values, and negative predictive values. Conclusion: Using the generated equations, the outcomes of COVID-19 patients can be predicted using commonly obtained clinical laboratory data. These predictive equations may inform future studies evaluating the long-term follow-up of COVID-19 patients.