Real-World Evidence: The Case of Peru

Real-World Evidence The Case of Peru

Causality Between Ivermectin and COVID-19 Infection Fatality Rate


Much has been said much about Peru and its use of Ivermectin as a treatment for the coronavirus. The South American country has been a point of reference regarding its use. The Peruvian government approved the use of Ivermectin by decree on May 8. Despite having received several requests to suspend it in September, Pilar Mazzetti, the new Minister of Health, ratified it. These measures have aroused much criticism among the scientific community. They do not understand why they continue to distribute the antiparasitic drug without having a randomized blind study to prove its effectiveness and overlook that the total death toll from COVID-19 in Peru is one of the world’s highest.

Turning away from opinions and moving on to facts, it is necessary to verify whether the ivermectin interventions have matched with variations in the virus’s mortality and lethality. And if they match a decrease in the number of new cases, a younger infected population, a substantial reduction in the most vulnerable people, or other factors could explain the variations.

This analysis evaluated the impact of ivermectin interventions on disease mortality and lethality. Specifically, it assessed the effect of large ivermectin distributions on the variation in the number of deaths associated with COVID-19 in the population older than 60 years, and the infection fatality rate in the same group.

In addition to focusing the study on the most vulnerable group, the study analyzes other factors that could cause variations in mortality, such as the number of positive cases in the same age group and the reduction in the population group’s size due to the deaths.

Graphical Analysis


It is well known that a correlation does not always imply causality. For a correlation to occur without causation, there must be external factors that generate either behaviors; or that the phenomena’ coincidence is the product of chance.

The correlation between the ivermectin interventions and the decrease in both mortality and lethality are quite strong and consistent in all the regions analyzed. However, this correlation could have been caused by other factors or as a product of an accident.

The most certain mechanism to rule out the accidental cause is to find the same correlation in several cases. This study has seen the correlation between Ivermectin’s intervention and the decrease in mortality and lethality in eight Peruvian states. Additionally, when analyzing two outcomes instead of one (mortality and lethality), a casual result becomes even more implausible. In this manner, we discard accidental cause as an explanation for the correlation.

Regarding external factors, we have already ruled out that they were caused by a higher percentage of the young population by including only people over 60 years of age in the study. We also rejected the variation in the number of cases when verifying that there was no decrease in these before reducing mortality. We even cancel out a substantial reduction in the susceptible population when confirming that in no case did deaths reduce this population by more than 1.2%.

Regarding susceptible population reduction at the time of the decrease (in mortality and lethality), these values were unequal in the states analyzed. As an example, the population reduction in Arequipa was four times higher than the decrease in Cusco.

A new theory emerged that some scientists say could explain the low mortality levels in some regions. It is a cross-immunity with dengue that would explain the low levels of mortality. This theory collapses by observing the high mortality rates in Peruvian states such as Arequipa or Moquegua, where there haven’t been dengue cases in the last 20 years. In those states, the mortality rose with COVID-19 cases and dropped after the intervention with Ivermectin.


In these eight Peruvian State analyses, ivermectin distributions preceded sound reductions in deaths amount and infection fatality rate. The variation in the number of detected cases or the vulnerable population decrease can’t explain the mortality and lethality improvement. Likewise, other possible explanations, such as crossed immunity with dengue, or mere causality, have been discarded due to their lack of consistency or implausibility.

The bottom line: treatment with Ivermectin is the most reasonable explanation for the decrease in the number of deaths and the fatality rate in Peru. Its implementation in public policies is a highly effective measure to reduce the mortality and lethality of COVID-19.

To read the full study, click here.

Juan Chamie is a data analyst based in Cambridge, Massachusetts. Recent employers and clients include Wayfair, Trivago, and TrueLight Energy. Get in touch with Juan via email or linkedin.


  1. I am not a doctor, nor a statistician, just an obsessed reader and listener on Covid 19 for 7 months. Any biased person or team of people can find a way to present a study to show what they want the reader to believe. However, after listening to well over a dozen experienced, front line doctors, professors and health professionals talk so passionately about their personal successes with Ivermectin, I still sit in shock, every day, wondering why it’s not being used everywhere. There have been over 5 billion doses given, and all my learned professors say it’s safe. How many more double blind, randomised, observational, open label, anecdotal studies do we need before we start believing the Intensivists and Critical Care Physicians who swear that it’s an effective treatment for Covid 19, given early, with Zinc, Doxycyline, Vitamin D and Vitamin C?

    1. Exactly, Bert Lannon! I am tired of watching people sicken and die across the country. The six people I know of with positive Covid tests in my own circle of acquaintances, ALL had their fevers disappear on day 2 of treatment with ivermectin and symptoms gone by days 5-7. I am betting the president got a dose early on… not that they’d share this with us peons.

  2. Sweden, New York City, Orange County, or California controlled the virus, reducing cases. It didn’t happen in Peru. The number of new cases and the test positivity remained constant (above 20%).

    Loreto is a good example. They controlled the deaths in May (with ivermectin). In July, a seroprevalence study shown a 71% infection rate. And still, the test positivity in October is above 30%

  3. Devil’s Advocate. Graphs similar to Peru have been observed in geographic regions where no intervention with ivermectin takes place (e.g., Sweden, New York City, Orange County, California). SARS-CoV-2 infection rates and deaths typically display a slow rise at first, followed by an exponental growth period, followed by a steep dropoff.

    I would like ivermectin (or, for that matter, any theraputic intervention) to be proved safe and effective. But, I don’t necessarily see that this particular study provides sufficient evidence of ivermectin’s efficacy.

    1. Hello,
      If it is true that a comparison would be lacking to show that in those districts it is lower than the average, for example, it could be compared with the districts in Peru that have not used ivermectin or have used it less, or even with the average of Peru
      With this, the study could show greater efficacy of ivermectin

  4. Interesting story. We live in Peru and our friend got us some in case. Was there a video documentary about this?

  5. Some people seem to be intent on avoiding ivermectin and decry and downplay any positive findings…
    …it has been tested and peer-reviewed positively in Bangladesh in an albeit small study-trial.
    Ivermectin is so safe that it should be given full status.
    One point five BILLION doses already used for other diseases must count for something.
    Get over it and use it.