What is a close contact?
by Ryan Ozawa
One of the most important tools in curbing the spread of a contagious virus like COVID-19 is contact tracing. Until COVID-19 vaccines are widely available to the general public later in 2021, contact tracing will remain a priority for public health officials and organizations.
Contact tracing usually involves a combination of technology and human talent and tenacity. It also requires adherence to best practices that ensure patient privacy. And one of the core concepts of contact tracing is identifying close contacts of a potentially infectious individual.
What is contact tracing?
As we’ve covered previously, the Centers for Disease Control (CDC) says that “contact tracing is part of the process of supporting patients and warning contacts of exposure in order to stop chains of transmission.
In contact tracing, public health staff first work with a COVID-19 patient to help them recall everyone with whom they have had close contact during the timeframe while they may have been infectious. They then begin contact tracing by warning these exposed individuals of their potential exposure as rapidly and sensitively as possible.
For contact tracing to work, communication with and the trust of the general public is crucial. Technology also plays a key role.
But contact between people can come in many forms, for varying lengths of time. Should a romantic partner be contacted? Or a coworker, Uber driver, neighbor, or cashier? A clear definition of close contact is necessary before the process can begin in earnest.
What is a close contact?
Fortunately, the CDC provides specific guidance on identifying a close contact, and even updates it as conditions evolve. In its Glossary of Key Terms, the CDC defines close contact as:
Someone who was within six feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period starting from two days before illness onset (or, for asymptomatic patients, two days prior to test specimen collection) until the time the patient is isolated.
If someone has been exposed to a COVID-19 patient several times within a 24-hour period, the time spent in close proximity is added together. So three five-minute face-to-face conversations would count as a 15-minute exposure.
Are other variables considered?
As simple as the definition of close contact might seem, a number of factors are taken into account. They include:
- Proximity: Closer distance likely increases exposure risk
- Duration: Longer exposure time likely increases exposure risk
- Symptoms: The period around the onset of symptoms is associated with the highest levels of contagion
- Respiratory aerosols: Coughing, singing, shouting, etc.
- Environmental factors: Crowding, ventilation, whether exposure was indoors or outdoors, etc.
“Because the general public has not received training on proper selection and use of respiratory PPE, such as an N95, the determination of close contact should generally be made irrespective of whether the contact was wearing respiratory PPE,” the agency notes. “At this time, differential determination of close contact for those using fabric face coverings is not recommended.”
What happens next?
Once a patient’s close contacts are identified, public health staff need to reach out to them to notify them of the potential disease exposure and advise them to seek testing and to self-quarantine in the meantime.
This notification process is often a time- and labor-intensive process, especially given federal privacy and security standards. Contact tracing and asymptomatic surveillance testing are most effective when utilizing an seamless, secure, and scalable method of communication.
With our HITRUST CSF certified product, patients receive encrypted emails directly to their inboxes—no passwords or portals required. Easy to implement with clear documentation, a developer’s experience is as seamless as the email recipient’s.