Throughout the coronavirus pandemic, the official guidance from the Centers for Disease Control and Prevention (CDC) was that people who spend at least 15 consecutive minutes within six feet of a person who tests positive for COVID-19 should quarantine and be tested, as they’re considered to have been in “close contact.”
This week, the agency updated their language defining “close contact” as someone who has spent 15 minutes or more over a 24-hour period within six feet of someone who has tested positive (nixing the consecutive requirement). The change came on Wednesday, following a study from the CDC and Vermont health officials in August, which found that multiple short-term exposures to someone who’s tested positive has led to transmission of the virus.
Researchers noted that the study, tracing transmission among people in a Vermont correctional facility, once again once again confirms that wearing masks is still a priority for staying safe from the virus and reducing the risks of transmission, noting that between individuals who tested positive there were instances of being in close contact with at least one of the parties not having their masks on for brief periods.
JUST IN—CDC is changes how “close contact” is defined. Instead of previously defining “close contact” as >=15 *consecutive* minutes w/in 6 feet of #COVID19 case, it’s now w/in 6 feet of an infected case for >=15 minutes cumulatively over 24-hours. Huge. 🧵 https://t.co/JLZd4Kdxm4
— Eric Feigl-Ding (@DrEricDing) October 21, 2020
Per the agency’s contact-tracing guidelines: “Someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period* starting from 2 days before illness onset (or, for asymptomatic patients, 2 days prior to test specimen collection) until the time the patient is isolated. Individual exposures added together over a 24-hour period (e.g., three 5-minute exposures for a total of 15 minutes). Data are limited, making it difficult to precisely define “close contact;” however, 15 cumulative minutes of exposure at a distance of 6 feet or less can be used as an operational definition for contact investigation. Factors to consider when defining close contact include proximity (closer distance likely increases exposure risk), the duration of exposure (longer exposure time likely increases exposure risk), whether the infected individual has symptoms (the period around onset of symptoms is associated with the highest levels of viral shedding), if the infected person was likely to generate respiratory aerosols (e.g., was coughing, singing, shouting), and other environmental factors (crowding, adequacy of ventilation, whether exposure was indoors or outdoors). 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 CDC guidelines note. “At this time, differential determination of close contact for those using fabric face coverings is not recommended.”
Ultimately, the change is one that is expected in a situation where we are still very much understanding how the virus moves through different groups, environments and bodies.
For day-to-day life this could potentially lead to more people being asked to quarantine after encounters with people who have tested positive. Close contact, in addition to being within six feet, can also include sharing eating or drinking utensils, hugging, kissing, providing home care to someone infected or if someone were to sneeze or cough on you.
Before you go, check out our favorite face masks to keep kids safe in the pandemic: