Employers screening for COVID-19 should consider updating their screening and other protocols following new guidance issued by the U.S. Centers for Disease Control (CDC) and a new study on how long the coronavirus can live on surfaces.
The new definition greatly expands persons who will be considered close contacts, and is just the latest change prompted by what scientists have learned regarding the spread of COVID-19. The CDC now also concedes that the virus can be “airborne” — a term with specialized meaning in the public health setting — but that is not the primary means of transmission. And another new study suggests the virus can live as long as 28 days on cold hard surfaces (such as an iPhone) – at least in an experimental laboratory setting.
Let’s take a closer look at these developments and how they impact employer protocols.
“Close Contact” Redefined
Previously, the CDC defined a “close contact” as someone who spent 15 or more consecutive minutes within six feet of someone with a confirmed case of COVID-19. Accordingly, employers screening employees for the virus typically ask about fever, symptoms, travel, and having close contact (within six feet for 15 consecutive minutes or more) with someone who had a confirmed case of COVID-19 or was awaiting a COVID-19 test.
Last week the CDC changed that definition to include a person who was within six feet of infected person for a cumulative total of 15 minutes in a 24-hour period. That 24-hour period starts from two days before the onset of symptoms or, for asymptomatic individuals, two days prior to test specimen collection until the patient is isolated.
How COVID-19 Spreads
We know that COVID-19 is spread primarily through exposure to respiratory droplets produced when an infected person exhales, including when they are breathing, speaking, singing, coughing, or sneezing. The CDC says that that larger droplets fall out of the air rapidly (within seconds to minutes) while close to the source, but smaller droplets and particles (formed when small droplets dry very quickly in the airstream) can remain suspended for “many minutes to hours and travel far from the source on air currents.”
The CDC recently updated its “How COVID-19 Spreads” website to acknowledge the potential for airborne transmission. It now notes three main ways the infection is transmitted:
- Contact transmission – such as touching during a handshake or contact with a surface that has been contaminated;
- Droplet transmission – inhaling droplets exhaled by an infectious person (most likely to occur when someone is within six feet of the infectious person); and
- Airborne transmission – through exposure to those smaller droplets and particles that can remain suspended in the air over long distances (usually greater than 6 feet) and time (typically hours).
These three modes of transmission are not mutually exclusive.
However, while the CDC notes that COVID-19 can be spread by airborne transmission, it also emphasizes that “the epidemiology of the virus ‘indicates that most infections are spread through close contact, not airborne transmission.’”
News reports suggest that the CDC internally had been discussing transmission for several weeks. Then, on October 21, 2020, the agency reported that a young prison employee contracted the virus after having numerous brief encounters that totaled only about 17 minutes in a 24-hour period with persons who later tested positive for the virus. The CDC report said that data suggested the infection was transmitted by one or more asymptomatic prisoners during one of those brief encounters. In its report on this incident, the CDC noted that “[a]dditional factors to consider when defining close contact include proximity, the duration of exposure, whether the infected person has symptoms, whether the infected person was likely to generate respiratory aerosols, and environmental factors such as adequacy of ventilation and crowding.”
Given that a significant percentage of those who have the virus don’t show symptoms, wearing a mask is important, the CDC stated “[w]hile a mask provides some limited protection to the wearer, each additional person who wears a mask increases the individual protection for everyone. When more people wear masks, more people are protected.”
The World Health Organization also emphasizes the importance of wearing masks: “[m]asks are a key measure to suppress transmission and save lives. Masks reduce potential exposure risk from an infected person whether they have symptoms or not. People wearing masks are protected from getting infected. Masks also prevent onward transmission when worn by a person who is infected. Masks should be used as part of a comprehensive ‘Do it all!’ approach including: physical distancing, avoiding crowded, closed and close-contact settings, improving ventilation, cleaning hands, covering sneezes and coughs, and more.”
The Virus’ Life on Surfaces
In its September 16, 2020 guidance, the CDC notes that “[c]oronaviruses on surfaces and objects naturally die within hours to days.” The agency notes that warmer temperatures and exposure to sunlight will reduce the time the virus survives on surfaces and objects, and that routine cleaning with soap and water removes germs and dirt from surfaces, and thus, lowers the risk of spreading COVID-19 infection. The CDC says that if your workplace, school, or business has been unoccupied for 7 days or more since an exposure to COVID-19, “it will only need your normal routine cleaning to reopen the area. This is because the virus that causes COVID-19 has not been shown to survive on surfaces longer than this time.”
However, on October 13, 2020, CBS News reported “[t]he coronavirus that causes COVID-19 can survive on items such as banknotes and phones for up to 28 days in cool, dark conditions, according to a study by Australia’s national science agency. Researchers at CSIRO’s disease preparedness centre tested the longevity of SARS-CoV-2 in the dark at three temperatures, showing survival rates decreased as conditions became hotter, the agency said Monday. The scientists found that at 68 degrees Fahrenheit, SARS-CoV-2 was ‘extremely robust’ on smooth surfaces — like cell phone and other touch screens — surviving for 28 days on glass, steel, and plastic banknotes. At 86 degrees Fahrenheit, the survival rate dropped to seven days and plunged to just 24 hours at 104 degrees Fahrenheit.”
Of course, those were laboratory conditions; in the real world, factors such as air flow, sunlight, and heat impact and weaken the virus. Scientists continue to believe the virus is rarely transmitted through contact with a contaminated surface. Indeed, the CDC has updated its “How Covid-19 Spreads” website to say: “Respiratory droplets can also land on surfaces and objects. It is possible that a person could get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or eyes. Spread from touching surfaces is not thought to be a common way that COVID-19 spreads.”
So, consider the risks depending on where you are, and adjust accordingly. Employees working in close quarters where many people are touching the same surface, i.e., door handles, light switches, photocopy machines, should be vigilant. They should avoid touching their faces and always wash their hands before they do so. And, while scientists generally consider it unnecessary to quarantine mail and wipe down groceries, the CDC still recommends regularly cleaning and disinfecting frequently touched surfaces.
Takeaways for Employers
Employers should adjust their screening questionnaires to reflect the new definition of “close contact” to inquire whether employees have been exposed to a COVID-19 positive person for a total of 15 minutes or more during a 24-hour period.
In addition, employers should try to ensure that employees do not share equipment such as headphones, dictaphones, and touchscreens, without first disinfecting the equipment. Frequently touched surfaces with multiple users should be cleaned and disinfected regularly.
With virus cases spiking again, employers should have well-developed mask and social distancing protocols that are enforced and should encourage employees to wash hands frequently. Employers also should encourage employees to observe the same standards off-duty, to protect themselves and others from spread of the virus. Finally, employers should continue to monitor the CDC and state and local health authorities for updated guidance.