Observations about sexual and other routes of SARS‐CoV‐2 (COVID‐19) transmission and its prevention

Sexual contact has been proposed as a route of transmission for the SARS‐CoV‐2 virus, which raises the question of alternate routes of transmission.¹ Angiotensin‐converting enzyme (ACE)2 receptors (ACE2‐R) may be present in epidermal basal cells, including those at the base of hair follicles, sebaceous and eccrine glands, smooth muscle cells, vascular endothelial cells, renal epithelial cells, and potentially even the testis.² Recent research shows that although the testicles do carry ACE2‐R and that some patients might present with symptoms of viral orchitis, viral DNA is not found within seminal fluid after infection. Furthermore, it is postulated that the viral load is likely to be too low to cross the blood–testis barrier, and that ACE2‐R concentration in the testis may be insufficient to permit viral entry.³ However, other types of sexual contact, such as oral–anal contact, may also be implicated in transmission, given that rectal swab testing is positive even with negative nasopharyngeal swabs.¹, ⁴ It therefore seems relevant to ask whether all tissues that express ACE2‐R are receptive to viral entry, and if they can also be a source of viral shedding. Although some authors have suggested that there is no evidence of sexual transmission for SARS‐CoV‐2, it is still an interesting hypothesis to bear in mind, as it could place some sexual minorities at disproportionately higher risk.

At this time, we think nasopharyngeal swabs probably remain the standard of diagnosis. The faecal–oral route, whether through sexual contact or not, is quickly becoming a recognized route of viral transmission.⁴ The wildlife markets at the epicentre of the outbreak are notoriously overcrowded and unhygienic. In such places, faecal contamination of food could be an overlooked source of human–human transmission, similar to that seen in diseases such as cholera and dysentery. If this is true, then the potential for SARS‐CoV‐2 to spread in refugee camps or the slums of cities in poorer nations is very real. This certainly needs to be addressed urgently as part of various strategies so that public health authorities, who are already enforcing social isolation, do not lock people down in situations where they can spread the virus easily because of lack of access to clean water. Keeping all this in mind, we recommend that hygiene rules be very strictly adhered to: nails cut as short as possible, hair tied back (it too can be contaminated with the virus) and avoidance of eyelash extensions. It would also be good to shave beards, taking into account the sebum secretion in beard hair; however, this could be a problem for those who need to maintain beards for religious purposes. Absolutely any tool used for personal hygiene (tweezers, scissors, comb, etc.) should be disinfected as often as appropriate, and of course, under no circumstances be lent to other people.

We propose that further study should be directed towards the theoretically possible skin–skin transmission, either directly or through vectors such as pets, flies, mosquitoes (by portage) or Demodex folliculorum, which can be proliferated either as spinulosis that roughens the skin of the cheeks and thorax, or in patients with rosacea.⁵