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Ivermectin in combination with doxycycline for treating COVID-19 symptoms: a randomized trial


Reaz, Mahmud et al. (2021), Ivermectin in combination with doxycycline for treating COVID-19 symptoms: a randomized trial, Dryad, Dataset,


Objective: We evaluated whether ivermectin combined with doxycycline reduced the time to clinical recovery in adults with COVID-19 infection.

Methods: This was a randomized, blinded, placebo-controlled trial in patients with mild-to-moderate COVID-19 symptoms randomly assigned to treatment (n = 200) and placebo groups (n = 200). The primary outcome was duration from treatment to clinical recovery. Secondary outcomes included disease progression and persistent COVID-19 positivity by RT-PCR.

Results: Among 556 screened patients, 400 were enrolled and 363 completed follow-up. The mean patient age was 40 years, and 59% were men. The median recovery time was 7 (4–10) and 9 (5–12) days in the treatment and placebo groups, respectively (hazard ratio, 0.73; 95% confidence interval, 0.60–0.90). The number of patients who recovered within 7 days was 61% and 44% in the treatment and placebo groups, respectively (hazard ratio, 0.06; 95% confidence interval, 0.04–0.09). The proportion of patients who remained RT-PCR positive on day 14 and whose disease did not progress was significantly lower in the treatment group than in the placebo group.

Conclusions: Patients with mild-to-moderate COVID-19 infection treated with ivermectin plus doxycycline recovered earlier, were less likely to progress to more serious disease, and were more likely to be COVID-19 negative by RT-PCR on day 14.



Patients were enrolled between 1 June 2020 and 30 August 2020. The inclusion criteria for enrollment were as follows: age greater than 18 years, positive COVID-19 RT-PCR test within 3 days prior to enrollment, and mild to moderately severe COVID-19 infection. Patients who were unable to receive oral medications, were pregnant or breastfeeding, had severe COVID-19 symptoms (defined as tachypnea [>30 breaths/minute] and hypoxia [SpO2 < 90%] at room air and requiring supplemental oxygen), were admitted to intensive care or high-dependency units, or had known hypersensitivities to ivermectin or doxycycline were excluded from participation.

Trial design

This was an investigator-initiated, placebo-controlled trial. The independent data safety monitoring board of Dhaka Medical College monitored treatment safety and efficacy. Routine investigations were performed at the pathology laboratory of Dhaka Medical College. RT-PCR tests were performed at the virology laboratory of Dhaka Medical College and Bangabandhu Sheikh Mujib Medical University. Ivermectin, doxycycline, and placebo preparations were provided by a popular pharmaceutical company.

Eligible patients were randomly assigned to the treatment group or the placebo group at a 1:1 ratio on day 1 of the trial. Group assignment was not stratified according to disease severity.

The allocation schedule was created with a list of random numbers generated using a random number generator program by the head of the Department of Medicine of Dhaka Medical College. Group assignment was concealed in sequentially numbered, opaque, sealed envelopes. The randomization code was maintained by the pharmaceutical company. Both the investigators and the patients were blinded to the treatment allocation.

Decoding was performed at the end of the trial under the supervision of the principal of the institute.

The trial was conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice guidelines, and was approved by the ethical review committee of Dhaka Medical College Hospital (ERC-DMC/ECC/2020/117). Dhaka Medical College is the largest tertiary care teaching hospital and the largest COVID-19 treatment hospital in Bangladesh. The trial was registered retrospectively at (identifier: NCT04523831). Written informed consent was obtained from all patients prior to participation. The study is reported according to the Equator Network Guidelines.

Study interventions

The treatment group received a single dose of ivermectin 12 mg and doxycycline 100 mg, twice daily for 5 days, in addition to standard of care. Standard of care included administration of paracetamol, antihistamines, cough suppressants, vitamins, oxygen therapy according to indication and need, low molecular weight heparin according to indication, appropriate other broad-spectrum antibiotics, remdesivir injection, other antiviral drugs, and other drugs for associated comorbid conditions.

The placebo group received placebo in addition to standard of care.

Experimental procedures

The baseline demographic and clinical characteristics of patients were recorded. The date of random assignment was considered as day 1, and all patients received their initial study intervention on day 1. Outpatients were followed daily until at least 3 days of clinical recovery were observed. Clinical recovery was defined as a normal body temperature of 36.1C to 37.2C maintained for at least 3 days, significantly improved respiratory symptoms (respiratory rate < 25/minute, no dyspnea), and oxygen saturation greater than 93% without assisted oxygen inhalation, as recommended by the World Health Organization and the national guidelines of Bangladesh.

Hospitalized patients were followed from day 1 through day 14 or until discharge or clinical improvement, whichever occurred later. Clinical status and vital signs (including respiratory status) were recorded daily. Adverse events as defined by the Medical Dictionary for Regulatory Activities (MedDRA) were documented.

Laboratory tests were performed on day 1, and included the following: complete blood count, random blood glucose, creatinine, alanine transaminase, C-reactive protein, ferritin, and D-dimer. Chest radiography or chest CT scanning were performed as needed. For outpatients, test results were documented at the next visit. Hospitalized patients were tested on days 1 and 7 and when ordered by the treating physicians. COVID-19 RT-PCR testing was performed 14 days after the initial positive test in all patients.

Outcome measures

The primary outcome was the number of days required for clinical recovery from day 1. Clinical recovery was divided into three categories: early recovery within 7 days, intermediate recovery within 7 to 11 days, and late improvement requiring 12 or more days for recovery. Secondary outcomes were disease progression through mild, moderate, severe, or death, and the proportion of patients who continued to test positive for COVID-19 on day 14. Adverse drug reactions (adverse events assumed to be caused by the study intervention) were also recorded. Mild disease was defined as symptoms of an upper respiratory tract viral infection, including mild fever, dry cough, sore throat, nasal congestion, headache, muscle pain, anosmia, and malaise. Moderate respiratory symptoms such as cough and shortness of breath were observed without signs of severe pneumonia. Severe disease included severe dyspnea, tachypnea (> 30 breaths/minute), and hypoxia (SpO2 < 90% at room air). These classifications were according to the World Health Organization and national guidelines of Bangladesh. The co-investigators assessed the outcome, graded the disease, and documented adverse reactions.

Statistical methods

We sought to enroll as many patients as possible in a short time. As a result, a priori power calculations were not performed. Instead, 200 patients were enrolled in each group and it was assumed that 20% of patients in each group would be lost to follow-up. A post-hoc power calculation [2SD2 (Zα/2+ Zβ) 2/d2]14 using a two-tailed test, an alpha level of 0.05, and SD 6 indicated that the enrollment of 141 patients in each group (170 before 20% attrition) would result in an 80% chance of detecting a 2-day difference in median recovery time.

Intention-to-treat analysis was performed. The difference in median recovery time was determined using Kaplan–Meier analysis and a log-rank test. Details of patients who were lost to follow-up, had died, or had withdrawn from the trial due to adverse effects were censored on the final study day. Differences in the clinical improvement in the three disease categories were analyzed using logistic regression. Hazard ratios (HRs) were calculated using Cox regression analysis. Categorical variables are presented as n (%), normally distributed continuous variables as mean (standard deviation [SD]), and skewed continuous variables as median (interquartile range [IQR]).

Subgroup analysis was performed using the logistic regression analysis. HRs were calculated using Cox regression analysis. Age group, sex, fever, cough, respiratory distress, hypertension, diabetes, and presence of any comorbidity were adjusted. Subgroups consisted of age (less than vs. more than 60 years), sex, presence or absence of any comorbidities, mild disease, moderate disease, hospital admission, and interval between disease onset and drug application interval (less than vs. more than 4 days from the onset of the disease). A forest plot was constructed to evaluate differences in the primary outcome among the subgroups. No corrections were made for multiple comparisons. All tests were two-tailed and the alpha was set at 0.05. Data were analyzed using SPSS software, version 20 (Armonk, NY: IBM Corp, USA).

Usage Notes


            A. Principal Investigator Contact Information

                        Name: Dr. Reaz Mahmud

                        Institution: Dhaka Medical College

            Address: Assistant Professor, Department of Neurology, Dhaka Medical

            College. Dhaka, Bangladesh. Phone-+8801912270803


            B. Associate or Co-investigator Contact Information

                        Name: Dr. Md. Mujibur Rahman

                        Institution: Dhaka Medical College Hospital

Address: Professor and Head, Department of Medicine, Dhaka Medical College

Hospital, Dhaka. Bangladesh Phone-+8801711525406


            C. Alternate Contact Information

                        Name: Dr. Farhana Binte Monayem

                        Institution: Sarkari karmachari Hospital

                        Address: Medical officer, Sarkari karmachari Hospital. Dhaka, Bangladesh



3. Date of data collection: 2020/06/01 to 2020/08/25

4. Geographic location of data collection: COVID-19 unit, Dhaka Medical College, Dhaka, Bangladesh

5. Information about funding sources that supported the collection of the data: Non-funded study


1. Licenses/restrictions placed on the data:

This work is licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license      

2. Links to publications that cite or use the data: Dryad:


3. Links to other publicly accessible locations of the data: None

4. Links/relationships to ancillary data sets: None

5. Was data derived from another source? No

            A. If yes, list source(s):

6. Recommended citation for this dataset:

Reaz, Mahmud et al. (2021), Association of ABO blood groups with presentation and outcomes of confirmed SARS CoV-2 infection: A prospective study in the largest COVID-19 dedicated hospital in Bangladesh, Dryad, Dataset,


1. File List:

Data set in SPSS

2. Relationship between files, if important:

3. Additional related data collected that was not included in the current data package:

4. Are there multiple versions of the dataset? No

            A. If yes, name of file(s) that was updated:

                        i. Why was the file updated?

                        ii. When was the file updated?


1. Description of methods used for collection/generation of data:

The manuscript has been accepted by PLOS ONE. DOI-10.1371/journal.pone.0249252

2. Methods for processing the data:

This single-center prospective cohort study was conducted to evaluate the association of the ABO blood groups with the presentation and outcomes of confirmed COVID -19 infections in hospitalized and outdoor patients with COVID-19. The outcomes in this research included: A. Duration required for clinical improvement, as defined below; B. Proportion of patients converted to the next level of severity; C. Proportion of the patients remaining positive for RT-PCR of COVID-19 on day 14 after the initial positivity; D. Development of post-COVID syndrome as defined below. The recruitment was limited to patients who were more than 18 years of age with confirmed COVID-19 (RT-PCR positive) infection. Patients with hemoglobinopathies or other blood disorders were excluded from the study. Written informed consent was obtained from all the patients. Ethical approval was obtained from the ethical review committee of the institute. For the estimation, we grouped A positive and A negative blood groups into group I and other blood groups, such as B, AB, and O, irrespective of their Rh status, into group II. An assumption that the expected proportions to be cured from COVID-19 by day 12 in group I (blood group A) and group II (blood groups B, O, AB) are 0.70 and 0.90, respectively. Thus, we required a total of 378 samples at a 1:2 ratio, which would provide a power of at least 90% in two-tailed tests and a p value less than 0.05, to detect significant differences between the groups. Therefore, considering a 10% dropout rate, we needed 416 samples in total.


A case record form was constructed to collect baseline information, such as demographics, blood groups, clinical signs and symptoms, comorbidities, and oxygen saturation. Routine investigations, including CBC, ESR, CRP, creatinine, RBS, SGPT, chest X-ray, and D-dimer were advised on enrollment. Real-time-polymerase chain reaction testing for COVID-19 was performed 14 days after the initial positive test in all patients. The patients were followed up directly or over the telephone with at least three-day intervals up to 30 days from the onset of the disease.

3. Instrument- or software-specific information needed to interpret the data:

The data were analyzed using STATA version-15.1, StataCorp, 4905 Lakeway Drive, College Station, Texas 77845 USA

4. Standards and calibration information, if appropriate:

5. Environmental/experimental conditions:

6. Describe any quality-assurance procedures performed on the data:

7. People involved with sample collection, processing, analysis and/or submission:

Principal investigator and Co-investigators of the study


1. Number of variables: 35

2. Number of cases/rows: 438

3. Variable List:

 Age group of the patients: 1=<40 years, 2=40-60 years, 3=>60 years

Gender: male -1or female-0

Fever: presence-1 or absence-0

Cough: presence-1 or absence-0

Running nose: presence-1 or absence-0

Respiratory distress: presence-1 or absence-0

Sore throat: presence-1 or absence-0

Hoarseness of voice: presence-1 or absence-0

Chest pain: presence-1 or absence-0

Diarrhea: presence-1 or absence-0

Vomiting: presence-1 or absence-0

Anorexia: presence-1 or absence-0

Anosmia: presence-1 or absence-0

Headache: presence-1 or absence-0

Lethargy: presence-1 or absence-0

Conjunctivitis: presence-1 or absence-0

Body ache: presence-1 or absence-0

Total duration of illness: duration required to have clinical recovery

Conversion to next level of severity: presence-1 or absence-0

Persistent positivity: presence-1 or absence-0

Post Covid syndrome: presence-1 or absence-0

Neursthaenia: presence-1 or absence-0

Blood group: A positive, A negative, B positive, B negative, O positive, O negative, AB positive, AB negative

Co-morbidity: presence-1 or absence-0

Diabetes: presence-1 or absence-0

Hypertension presence-1 or absence-0


Severity of illness: Mild and moderate

Response within 7 days: Yes -1 No-0

Response after 12 days; Yes-1 No -0

Ultimate severity: At the end Mild moderate and severe

Rh exclusion: Only ABO blood group irrespective of Rh phenotype

Comorbidity single: mere presence or absence of any co-morbidity

A and non A: Group A: A positive, A negative, Non A: B negative, O positive, O negative, AB positive, AB negative

Outcome death or alive:

4. Missing data codes: 99, 98 etc

Clinical Recovery:

Clinical improvement or recovery in patients was assessed according to the improvement criteria of the WHO and Bangladesh guidelines which required that the body temperature remained normal for at least 3 days, respiratory symptoms were significantly improved (respiratory rate < 25 and no dyspnea), and SpO2 >93% was achieved without assisted oxygen inhalation.

Respiratory distress; Shortness of breath, respiratory rate >25/min, or oxygen saturation <93%

Severity of the disease:  

Mild disease was defined as the symptoms of an upper respiratory tract viral infection, including mild fever, cough (dry), sore throat, nasal congestion, malaise, headache, muscle pain, anosmia, or malaise.

Moderate disease, including respiratory symptoms, such as cough and shortness of breath are present without signs of severe pneumonia. 

Severe disease included severe dyspnea, tachypnea (> 30 breaths/min), and hypoxia (SpO2 < 90% in room air). These classifications were made according to the World Health Organization and national guidelines of Bangladesh.

In this study, we assessed the proportion of patients with early recovery (clinical improvement within 7 days of symptom onset), late recovery (clinical improvement required ≥12 days),

Severity conversion (patients progress to more serious disease),

Persistently positive for RT-PCR of COVID-19 (positive RT-PCR on a 14 day test), and

 Post-COVID syndrome (in the absence of any definition, we defined it as 1. Persistence of illness with signs and symptoms beyond virologic clearance 2. Development of new symptoms within 1 month after the initial clinical and virologic cure, the etiology of which is postulated to be viral infection.