Increasing opium use in Iran in response to unsubstantiated rumors that it protects against COVID-19.

We write to address misconceptions identified by some commentators on the alleged protective effects of opium consumption and the SARS‐CoV‐2 virus [1]. This mistaken news caused a flood of opium use in the Iranian society, as field reports from the main squares for the sale of opium, including Shush Square in Tehran, indicated a five to six times increase in the number of customers [2]. Also, some preliminary scientific findings on the protective effects of opium use against SARS‐CoV‐2 infection led to pseudoscientific speculations on the veracity of this popular belief [3]. For instance, it has been proposed that short‐term opium use competes with binding of SARS‐CoV‐2 to the angiotensin converting enzyme 2 (ACE‐2) receptors and suppresses serum levels of interleukins involved in COVID‐19‐associated hyperinflammatory syndrome [4], but most evidence did not support the claims that opium consumption reduced the risk of contracting COVID‐19 or of the severity of infection acquired. Indeed, most studies have reported opium use as a triggering or aggravating factor of COVID‐19 [5, 6]. So, what is the reason for an increased mortality rate from COVID‐19 among individuals who use opium? According to a critical review of recent literature on short‐term effects of opium consumption, there are five main relevant reasons: (i) down‐regulation of anti‐viral cytokine expression such as interferon (IFN)‐α and IFN‐γ; (ii) development of pulmonary edema following endothelial dysfunction; (iii) increase thrombotic factors such as plasma fibrinogen and plasminogen activator inhibitor 1; (iv) increase ACE‐2 via stimulating silent information regulator 1 expression; (v) increased risk of pneumonia due to their effect on the medullary respiratory centers and decreased ventilation; and (vi) QT interval prolongation [7, 8, 9].

The morphine‐induced immune modulation can also be affected by the chronicity of using this class of agents. In this regard, a systematic review of in‐vitro studies has revealed that morphine at high doses and over several months could increase the risk of bacterial infections by inhibiting the cellular immune system [10]. Another related study suggested that long‐term opium use may be associated with suppression of B and T lymphocyte proliferation, induction of necrosis and apoptosis in immune cells and thymic and splenic atrophy [11]. Recent evidence has also shown that opium, as an immunosuppressive agent, can reduce leukocyte activity by inhibiting the migration of bone marrow‐derived cells in the long term [12]. Regardless of the action mechanism of morphine, the scientific consensus has been on its detrimental effects on the immune system and the reasons for the increased risk of mortality among opium‐addicted patients with COVID‐19 [7]. Because individuals may be rapidly affected by each other’s emotional reactions, policymakers and professionals in Iran and world‐wide should be aware of the rumors and the potential risk of ‘emotional contagion’ among the general population. Indeed, raising public awareness about the adverse effects of opium on the clinical course of COVID‐19 can be effective in reducing its mortality rate.

DECLARATION OF INTERESTS

None.