Surgical mask in the context of "Sneeze"

A sneeze (also known as sternutation) is a semi-autonomous, convulsive expulsion of air from the lungs through the nose and mouth, usually caused by foreign particles irritating the nasal mucosa. A sneeze expels air forcibly from the mouth and nose in an explosive, spasmodic involuntary action. This action allows for mucus to escape through the nasal cavity and saliva to escape from the oral cavity. Sneezing is possibly linked to sudden exposure to bright light (known as photic sneeze reflex), sudden change (drop) in temperature, breeze of cold air, a particularly full stomach, exposure to allergens, or viral infection. Because sneezes can spread disease through infectious aerosol droplets, it is recommended to cover one's mouth and nose with the forearm, the inside of the elbow, a facial tissue or a handkerchief while sneezing. In addition to covering the mouth, looking down is also recommended to change the direction of the droplets spread and avoid high concentration in the human breathing heights.

The function of sneezing is to expel mucus containing foreign particles or irritants and cleanse the nasal cavity. During a sneeze, the soft palate and palatine uvula depress while the back of the tongue elevates to partially close the passage to the mouth, creating a venturi (similar to a carburetor) due to Bernoulli's principle so that air ejected from the lungs is accelerated through the mouth and thus creating a low pressure point at the back of the nose. This way air is forced in through the front of the nose and the expelled mucus and contaminants are launched out the mouth. Sneezing with the mouth closed does expel mucus through the nose but is not recommended because it creates a very high pressure in the head and is potentially harmful.

During the COVID-19 pandemic, face masks or coverings, including N95, FFP2, surgical, and cloth masks, have been employed as public and personal health control measures against the spread of SARS-CoV-2, the virus that causes COVID-19.

In community and healthcare settings, the use of face masks is intended as source control to limit transmission of the virus and for personal protection to prevent infection. Properly worn masks both limit the respiratory droplets and aerosols spread by infected individuals and help protect healthy individuals from infection.

In health care facilities, isolation represents one of several measures that can be taken to implement in infection control: the prevention of communicable diseases from being transmitted from a patient to other patients, health care workers, and visitors, or from outsiders to a particular patient (reverse isolation). Various forms of isolation exist, in some of which contact procedures are modified, and others in which the patient is kept away from all other people. In a system devised, and periodically revised, by the U.S. Centers for Disease Control and Prevention (CDC), various levels of patient isolation comprise application of one or more formally described "precaution".

Isolation is most commonly used when a patient is known to have a contagious (transmissible from person-to-person) viral or bacterial illness. Special equipment is used in the management of patients in the various forms of isolation. These most commonly include items of personal protective equipment (gowns, masks, and gloves) and engineering controls (positive pressure rooms, negative pressure rooms, laminar air flow equipment, and various mechanical and structural barriers). Dedicated isolation wards may be pre-built into hospitals, or isolation units may be temporarily designated in facilities in the midst of an epidemic emergency.

Source control is a strategy for reducing disease transmission by blocking respiratory secretions produced through breathing, speaking, coughing, sneezing or singing. Multiple source control techniques can be used in hospitals, but for the general public wearing personal protective equipment during epidemics or pandemics, respirators provide the greatest source control, followed by surgical masks, with cloth face masks recommended for use by the public only when there are shortages of both respirators and surgical masks.