Internet Searches for Unproven COVID-19 Therapies in the United States

Michael Liu, Theodore L. Caputi, Mark Dredze, et al

Published online April 29, 2020.


There are no highly effective prescription drug therapies supported by any reliable evidence for the ongoing coronavirus disease 2019. However, fears among the public can lead to searches for unproven therapies. Therefore, when several high-profile figures, including entrepreneur Elon Musk and President Donald Trump, endorsed the use of chloroquine, a malarial prophylaxis drug, and hydroxychloroquine (with the antibiotic azithromycin), a lupus and rheumatoid arthritis treatment, to treat COVID-19, it drew massive public attention that could shape individual decision-making.

The query fraction (QF) of Google searches per 10 million for purchasing chloroquine on February 1, March 16, March 22, and March 29 were 4.78 (equivalent to 542 estimated searches), 26.90 (3052 estimated searches), 66.16 (7506 estimated searches), and 19.19 (2177 estimated searches), respectively. The QFs for purchasing hydroxychloroquine on February 1, March 16, March 22, and March 29 were 4.35 (494 estimated searches), 7.68 (871 estimated searches), 79.37 (9006 estimated searches), and 31.95 (3625 estimated searches), respectively. Queries for purchasing chloroquine were 442% (95% CI, 215%-1220%) higher following high-profile claims that these drugs were effective COVID-19 therapies. Similarly, searches for purchasing hydroxychloroquine were 1389% (95% CI, 779%-2021%) higher. The first and largest spike in searches corresponded directly with Musk’s tweet and Trump’s first televised endorsements, respectively, with the latter occurring on March 19 (chloroquine QF, 249.58 [28 319 estimated searches]; and hydroxychloroquine QF, 179.00 [20 311 estimated searches]). These changes represent about 93 000 and 96 000 more searches than expected for chloroquine and hydroxychloroquine, respectively, with 216 000 total searches for both drugs over just 14 days.

Following news reports of the first fatal poisoning, searches to buy chloroquine or hydroxychloroquine remained substantially above expected levels at 212% (95% CI, 66%-1098%) and 1167% (95% CI, 628%-1741%) higher, respectively.

This attention is especially troublesome because chloroquine and hydroxychloroquine (1) are thus far only known to inhibit severe acute respiratory syndrome coronavirus 2 in vitro, (2) have potential cardiovascular toxic effects, and (3) can be confused with commercially available chloroquine-containing products, such as aquarium cleaner. Poisonings, including 1 fatality, attributed to persons taking chloroquine to prevent or treat COVID-19 without the supervision of a licensed physician have already been reported.