What surveillance data exist on poison center calls and hospitalizations linked to veterinary ivermectin misuse during the COVID-19 pandemic?
Executive summary
Surveillance during the COVID-19 pandemic documented a clear rise in poison control center reports of human exposures to ivermectin — including veterinary formulations — with U.S. poison center calls increasing several-fold above pre-pandemic baselines in 2021 [1] [2] [3]. Public-health notices and clinical case series likewise describe increased adverse effects and episodes of severe illness requiring medical care, but there is no single, comprehensive national hospitalization registry that isolates veterinary-ivermectin misuse from other ivermectin exposures [4] [5] [3].
1. Poison center call surveillance: the primary signal and how big it was
Poison control center data, aggregated by the American Association of Poison Control Centers and cited by CDC health advisories, provide the clearest surveillance signal: calls for human exposures to ivermectin rose sharply in 2021 compared with a pre-pandemic baseline, with a roughly three-fold increase in January 2021 and continuing to about a five-fold rise by July 2021 in some reports [1] [2]. Multiple state health alerts repeated that the CDC confirmed increases in human exposures and adverse effects reported to poison control centers, and specifically noted an uptick in use of veterinary formulations not intended for human consumption [3] [1]. The FDA and professional outlets warned early that increased public visibility of ivermectin could drive misuse and asked clinicians to report unapproved uses [6].
2. Hospitalizations and severe illness: scattered clinical reports, no single national count
Clinician-facing alerts and hospital case series document instances of severe toxicity and hospital presentations linked to ivermectin misuse, including exposures to veterinary products that deliver much higher doses than human formulations; CDC and state health departments highlighted increases in adverse effects and some severe illnesses requiring clinical intervention [4] [3]. Academic case-characterization work from U.S. centers compared toxicity from veterinary versus human formulations and described rapid-onset neurotoxicity and other harms in people ingesting veterinary products, indicating that some exposures resulted in clinically significant illness necessitating medical care [5]. However, the available sources do not present a single, harmonized national hospitalization database isolating veterinary-product exposures, so quantifying total hospitalizations attributable specifically to veterinary ivermectin misuse is not possible from the cited surveillance products alone [5] [4].
3. What surveillance systems contributed data and their limits
The primary data streams cited are poison control center call logs (AAPCC), pharmacy dispensing trends, and ad hoc state and CDC health advisories that synthesize those signals; FDA and state health departments also relied on clinician reports and informal supply indicators from veterinarians and pharmacies [1] [2] [6] [3]. Poison center calls are timely and sensitive for detecting exposures but are subject to reporting bias, variable clinical detail, and undercounting of cases that never contact poison control; pharmacy dispensing data show increased dispensing of ivermectin but do not distinguish veterinary versus human-intended use in all cases [1] [3]. Hospital case series add clinical depth but are localized and cannot be extrapolated to a national incidence without broader surveillance [5].
4. Geographic and sociopolitical context that shaped surveillance and interpretation
Surveillance findings intersected with political and social factors: analyses and reviews note that prescribing and demand patterns for ivermectin correlated in some areas with political affiliation and with misinformation campaigns, complicating interpretation of why exposures rose and which portions of the increase represented veterinary-product misuse [7]. Internationally, misuse of veterinary ivermectin also occurred in Latin America and other regions, and mixed-methods research explored underlying drivers — scarcity of alternatives, community beliefs, and supply chains — which shaped the types of surveillance signals public health agencies observed [8].
5. Bottom line and gaps for further investigation
The surveillance record shows a reproducible, multi-source signal: poison control center calls for ivermectin exposures surged in 2021, public-health advisories documented increased adverse effects and some severe illness linked to veterinary formulations, and hospital case reports documented clinically important toxicities [1] [2] [4] [5]. Nonetheless, no single source in the provided reporting offers a definitive national count of hospitalizations solely attributable to veterinary ivermectin misuse; quantifying that burden would require linked poison-center, pharmacy, and hospital discharge data with standardized exposure coding — a gap the cited materials acknowledge implicitly by relying on aggregated call counts, clinical case series, and state advisories [1] [5] [3].