How long should someone wear a mask after testing positive for Coronavirus (COVID-19)?

From the Guidelines

After testing positive for COVID-19, you should wear a mask for at least 10 days after your positive test, as this is the recommended self-isolation period for mild to moderately symptomatic patients, according to the UK and World Health Organization guidelines 1. When considering the duration of mask-wearing after a positive COVID-19 test, it's essential to prioritize the protection of others, as the virus can be contagious for several days after symptoms begin.

• The virus is most contagious in the 2 days before and the 5 days after the onset of symptoms, but it's rare for the virus to be cultured beyond 10 days after symptom onset 1.
• In severely ill or severely immunocompromised patients, infectivity may continue for longer, up to 15-20 days after symptom onset 1.
• It's crucial to note that PCR positivity does not correlate with secretion of live virus, so it's of little or no value in assessing the risk of infectivity in the 3 months after confirmed SARS-CoV-2 infection 1. Key considerations for mask-wearing after a positive COVID-19 test include:
• The severity of symptoms, with mild to moderately symptomatic patients requiring 10 days of self-isolation and severely ill patients requiring 15-20 days 1.
• The use of high-quality masks, such as N95 or KN95, when around others, especially those who are at higher risk for severe disease.
• The importance of continuing to wear a mask in crowded indoor settings until day 10 to further reduce transmission risk.

From the Research

Duration of Mask Wear After Testing Positive for COVID-19

The duration for which someone should wear a mask after testing positive for Coronavirus (COVID-19) is not explicitly stated in the provided studies. However, the studies offer insights into the effectiveness of mask-wearing in preventing the transmission of SARS-CoV-2, the virus that causes COVID-19.

Effectiveness of Masks in Preventing Transmission

• The use of face masks or respirators is recommended to reduce transmission of SARS-CoV-2 2.
• Well-fitting face masks and respirators effectively filter virus-sized particles in laboratory conditions 2.
• A study found that always using a face mask or respirator in indoor public settings was associated with lower adjusted odds of a positive test result compared with never wearing a face mask or respirator in these settings 2.
• Wearing N95/KN95 respirators or surgical masks was associated with significantly lower adjusted odds of a positive test result compared with not wearing any face mask or respirator 2.

Transmission Modes and Mask Effectiveness

• The transmission modes of COVID-19 virus include droplets and aerosols, and masks play a role in disease prevention and transmission reduction 3.
• The effectiveness of different types of masks under varied environmental conditions is discussed, with an emphasis on both exhalation isolation and inhalation protection 3.
• A study found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2 4.

Guidelines for Healthcare Workers

• The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) have issued guidelines for contact and droplet precautions for healthcare workers caring for suspected COVID-19 patients 5.
• The evidence base for current guidelines is sparse, and the available data do not support the 1- to 2-meter (≈3-6 feet) rule of spatial separation 5.
• A study found that exhaled SARS-CoV-2 can be quantified by face-mask sampling in hospitalized patients with COVID-19, and higher face-mask sampling viral loads were associated with developing severe disease 6.