Ivermectin and the odds of hospitalization due to COVID-19: evidence from a quasi-experimental analysis based on a public intervention in Mexico City

In December 2020, before COVID vaccines became widely available, Mexico City experienced a surge in cases and hospitalizations. The city government expanded a population-based health intervention that consisted of early detection, phone-based follow up for positive cases, and the distribution of a medical kit containing ivermectin, aspirin and paracetamol. The kits were provided by physicians and recipients were given instructions on how to use them.

The decision to include ivermectin in the kits was taken based on a recommendation from a working group of national and international medical experts.

A retrospective, quasi-experimental analysis was published in May 2021 on the website SocArXiv. The aim of the paper was to help understand the effects of the intervention. Based on an analysis of administrative data, the research found a significant reduction in hospitalization.

Read the paper here.

In February 2022, SocArXiv’s steering committee decided to censor the paper, unilaterally withdrawing it in an unprecedented move. SocArXiv describes itself as an “open archive” dedicated to “opening up social science, to reach more people more effectively, to improve research, and build the future of scholarly communication.”

Philip N. Cohen, SocArXiv’s director, published a justification for the decision here. He states that, “a widely shared Twitter thread argued that the authors, through their agency dispensing the medication, unethically recruited experimental subjects, apparently without informed consent, and thus the study is an unethical study.”

The authors published a response, refuting Cohen’s claims, here in which they state, “the paper used secondary data (administrative data) and the analysis was conducted AFTER the policy was implemented. We never ‘recruited experimental subjects,’ as Philip Cohen misinformed.”