Table 1.

Major hydroxychloroquine events from the start of the COVID-19 pandemic to December 2021

Intervention in model		Date in 2020		Description
1	Pulsea	March	11	The World Health Organization (WHO) declared COVID-19 a pandemic.70
			9, 18	Yao et al. and Liu et al. suggested hydroxychloroquine inhibits SARS-CoV-2 in vitro.6,7
			19	Then-President Trump endorsed hydroxychloroquine in a White House press briefing.9
			20	Gautret et al. suggested hydroxychloroquine efficiently clears nasopharyngeal carriage of SARS-CoV-2 in a small, open-label, non-randomized clinical trial.8
			21	Then-President Trump cited Gautret et al. in a tweet supporting hydroxychloroquine use.9
			28	The FDA issued an emergency use authorization for hydroxychloroquine.10
(i)	Not includeda	April	24	The FDA issued a drug safety communication for hydroxychloroquine (reports of serious arrhythmia).11
(ii)	Not includeda	May	18	Then-President Trump said he was taking hydroxychloroquine prophylactically.9
			22	Mehra et al. suggested hydroxychloroquine increased in-hospital mortality in a large, multinational registry analysis (retracted on June 4).71
(iii)	Not includeda	June	4	Mehra et al. retracted their paper because they were unable to independently verify their data set.72
			5, 19, 19	Three large randomized controlled trials (RECOVERY, Solidarity, and ORCHID) closed enrolment early because of no observed benefit in mortality.12–14
			15	The FDA revoked the emergency use authorization for hydroxychloroquine.10
(iv)	Not includeda	July	27	Then-President Trump tweeted a viral video supporting hydroxychloroquine use that was later removed by major social media platforms.9

^aMajor hydroxychloroquine events occurred every month from March to July 2020. It is difficult to model and interpret interventions when there are few or no time points separating them. Hence, we only included the first intervention (March 2020) in the models.