COVID-19 is not classified as a sexually transmitted infection (STI), meaning it is not primarily passed through semen or vaginal fluids. However, sexual activity presents a high risk for SARS-CoV-2 transmission due to the prolonged, close physical contact involved. The danger comes from the behaviors inherent to intimacy, which facilitate the exchange of respiratory particles between partners. The question of transmission during sex is therefore less about bodily fluids and more about physical proximity.
Primary Modes of COVID-19 Transmission
The virus that causes COVID-19, SARS-CoV-2, spreads mainly through respiratory droplets and aerosols expelled by an infected person when they breathe, talk, cough, or sneeze. Larger respiratory droplets typically infect a person within a close range, generally considered a few feet. Smaller particles, known as aerosols, can remain suspended in the air for longer periods and travel greater distances, especially indoors. Transmission occurs when a person inhales air contaminated with these virus-containing particles, and the risk increases with the duration and closeness of the interaction.
Is SARS-CoV-2 Found in Sexual Fluids?
Studies have investigated whether SARS-CoV-2 can be transmitted through sexual fluids, focusing on semen and vaginal secretions. While viral RNA has occasionally been detected in these fluids, the presence of infectious, live virus is rare. A systematic review suggested that the proportion of individuals with detectable SARS-CoV-2 RNA was very low in both semen (around 1.6%) and vaginal secretions (2.7%). Current evidence indicates that sexual transmission through these fluids is unlikely to be a major route of spread. Therefore, common barrier methods, such as condoms, would not prevent the primary mode of transmission during sexual activity, which is respiratory.
Assessing Risk During Close Physical Contact
The risk of contracting COVID-19 during sexual activity is related almost entirely to the close proximity of the partners. Intimate contact involves prolonged face-to-face interaction, substantially increasing the exchange of respiratory droplets and aerosols. Activities like heavy breathing, yelling, or singing, which can occur during sex, increase the amount of viral particles expelled. Kissing is a high-risk activity because it involves the direct exchange of saliva, which carries high concentrations of the virus. This deposits virus-laden fluids directly onto the mucous membranes of the mouth and nose, elevating the overall risk significantly beyond a casual encounter.
Guidance for Reducing Intimacy-Related Risk
The safest partner during a period of high transmission is someone who lives in the same household and is not exhibiting symptoms. For those engaging with partners outside their immediate household, avoiding sex when either person feels unwell or has been recently exposed is a necessary precaution. Simple behavioral adjustments can help mitigate the respiratory risk inherent in physical intimacy.
Behavioral Adjustments
Avoiding kissing and choosing sexual positions that do not involve face-to-face contact can reduce direct exposure to respiratory particles. Washing hands and any shared sex toys before and after sexual activity can also help reduce the potential for transmission from surfaces or skin contact.