TRANSMISSION, INFECTION PREVENTION & CONTROL-COVID-19 KNOWN TO DATE
Updated: Jun 27, 2020
Incubation period: Current estimates of the incubation period range from 1-14 days with median estimates of 5-6 days between infection and the onset of clinical symptoms of the disease.
Transmission: Asymptomatic transmission refers to transmission of the virus from a person, who does not develop symptoms. Transmission can happen from animals and human-to-human. Asymptomatic cases have been reported as part of contact tracing efforts in some countries. WHO regularly monitors all emerging evidence and provides updates.
Modes of transmission: Droplets sprayed by affected individuals, contact with patient respiratory secretions, contaminated surfaces and equipment.
Currently no sure treatment or vaccination, supportive measures only. Many companies and universities globally are rushing to create coronavirus vaccines, and human trials have already started for several manufacturers, including Pfizer, BioNTech etc.
Primary modes of transmission:
Droplet: Respiratory droplets (particles >5-10 μm in diameter) are generated when an infected person coughs or sneezes. Any person who is in close contact (within 1 m) with someone who has respiratory symptoms (coughing, sneezing) is at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets.
Contact: direct contact with infected people and indirect contact with surfaces in the immediate environment of or with objects used on the infected person (e.g., stethoscope or thermometer) (droplets may land on surfaces where the virus could remain viable).
Airborne transmission: Mainly limited to circumstances and settings in which aerosol generating procedures (AGPs): tracheal intubation, non-invasive ventilation, tracheotomy, CPR, manual ventilation before intubation, bronchoscopy.
Additional measures/precautions are based on modes of transmission:
Direct modes:
Direct contact
Direct contact occurs through touching; an individual may transmit microorganisms to others by skin-skin contact or contact with infected surfaces, soil or vegetation.
Droplet spread
Droplet spread refers to spray with relatively large, short-range aerosols produced by sneezing or coughing.
Indirect modes:
Indirect contact:
Indirect transmission refers to the transfer of an infectious agent from a reservoir to a host.
Airborne transmission occurs when infectious agents are carried by dust or droplet nuclei suspended in air.
Vehicles may indirectly transmit an infectious agent.
Vectors may carry an infectious agent or may support growth or changes in the agent.