10/8/20 COVID-19 Brief: CDC Acknowledges Airborne Transmission: Implications for Employers

On Monday, October 5th the US Centers for Disease Control updated its "How COVID-19 Spreads" web page to include new content under the heading “COVID-19 can sometimes be spread by airborne transmission.” Let’s focus on three questions employers need answered: What? So what? & Now what?

A Message on COVID-19 from WorkSTEPS Chief Medical Officer Dr. Ben Hoffman

CDC Acknowledges Airborne Transmission: Implications for Employers

On Monday, October 5th the US Centers for Disease Control updated its "How COVID-19 Spreads" web page to include new content under the heading “COVID-19 can sometimes be spread by airborne transmission.” Let’s focus on three questions employers need answered: What? So what? & Now what?

What is Airborne Transmission?

The CDC believes that COVID-19 is most often transmitted through close contact, and happens when an infected person coughs, sneezes, sings, talks or breathes, producing respiratory droplets that are then inhaled or land in someone’s mouth, nose, or eyes.

Monday’s update acknowledges that – in addition to close contact transmission – COVID-19 can be spread through airborne transmission under certain circumstances. Let’s be clear about key terms here:

  • Airborne transmission: Means the virus can be carried by droplets that are small enough to hang in the air for hours. Notably, because the droplets are very small, they need to reach a sufficient concentration in the air to be able to infect someone. See this WSJ article for a helpful graphic.
  • Certain circumstances: Aerosol transmission depends on two things: 1) The release of tiny droplets into the air; and 2) those droplets achieving sufficient concentration to provide a dose of virus that is enough to cause infection. These two conditions are met when: A) people are indoors; B) the space is poorly ventilated (allowing for the concentration of virus to build); and C) people are not wearing face coverings.

So What? Why Does This Matter?

The acknowledgment of aerosol spread introduces some important exceptions to the rules that have governed prevention strategies:

  • Social Distancing: Six feet is not always enough. Very small aerosol particles can travel much farther than six feet.
  • Close Contacts: When Contact Tracers look for people who may have been infected by someone diagnosed with COVID-19, they look for people who have been within 6 feet of the infected person for 15 minutes or more. Aerosol transmission breaks both of these rules. If virus-contaminated particles reach sufficient concentration, “close contact” is not required. In fact, COVID-19 can be transmitted even after an infected person leaves the room.

Now What? What Should Employers Do Differently?

First, let’s review the “certain conditions” under which aerosol transmission is thought to occur, namely: A) people are indoors; B) the space is poorly ventilated (allowing for the concentration of virus to build); and C) people are not wearing face coverings.

With these parameters in mind:

  • If you have been implementing comprehensive COVID-19 prevention measures, including proper ventilation, you don’t need to change anything.
  • However, this new information should motivate all employers to audit their interior spaces, looking for poorly-ventilated rooms being used by employees. In particular, look for conference rooms or break rooms (formal and informal) that have become more heavily used in recent months as employees have returned to work and/or have become less cautious in their behaviors.
  • If you haven’t yet adopted a comprehensive prevention strategy, this news is yet another reason to focus on prevention. And if you are struggling to get employees to comply with distancing and mask-wearing, know there is value in focusing on proper ventilation, which will provide protection regardless of compliance.
  • Finally, find ways to share this information with your employees. Educate them to identify and avoid poorly-ventilated indoor spaces (bars, restaurants, house parties), and encourage mask-wearing when in public settings outside of work.

The WorkSTEPS COVID-19 Brief reaches literally thousands of corporate health and safety professionals each week. We take seriously our responsibility to identify critical issues and to present important and actionable insights that help people like you keep employees, contractors, families and even communities safer during this pandemic. If there is an issue you’d like to see us address, or if you have any feedback on the job we’re doing, please let us know.

Ben Hoffman, MD, MPH
Chief Medical Officer, WorkSTEPS

For more from Dr. Hoffman, connect with him on LinkedIn.


Area Reported Cases Deaths Recovered
Global 36,129,503 1,056,048 27,197,336
United States 7,727,681 215,921 4,937,832

Summer family gathering leads to COVID-19 outbreak: On Monday, an investigation by the CDC concluded that a coronavirus outbreak at a 3-week family gathering likely originated from a 13-year-old girl who was exposed to a large outbreak 6 days before arriving. The family gathering went on to cause infections in people across four states. Fourteen relatives (including the index patient) stayed in a vacation house from 8 to 25 days, and eleven relatives contracted COVID-19. Six others visited outside in a physically distanced manner on two days for 10 hours, and the more cautious relatives did not get infected. Prior to the gathering, the index patient received a rapid antigen test 4 days after her exposure, which came back negative. Researchers stated this was probably because the test was meant to be used within the first 5 days of symptoms, and she was asymptomatic. The only symptom she displayed was nasal congestion on day 6, which was also the start of the family gathering. This report echoes the importance of quarantining after any exposure, confirming negative rapid antigen tests, and following physical distancing and mask guidelines. CDC released guidance on hosting gatherings or cook-outs.

Outbreaks are again increasing in the US: The number of new cases per day has risen more than 25 percent since mid-September. At least 721 new coronavirus deaths and 42,553 new cases were reported nationally on October 6. Over the past week, there have been an average of 44,116 cases per day, an increase of 6 percent from the average two weeks earlier. Case numbers remain persistently high across much of the country, this time hammering rural America and smaller cities and putting New York on high alert.

FDA releases EUA criteria for vaccines: On Tuesday, the FDA issued EUA criteria for COVID-19 vaccine makers. According to the revised rules, the FDA wants vaccine manufacturers of two-dose vaccines to collect safety data on at least half of their clinical trial subjects for two months after they have received their second dose. This guidance is being implemented without prior public comment because the FDA has determined that prior public participation for this guidance is not feasible or appropriate  (see section 701(h)(1)(C) of the Federal Food, Drug, and Cosmetic Act. All but one of the current frontrunners follow a two-dose regimen.

Frequent manifestation of neurologic symptoms in hospitalized patients: On Tuesday, a study released revealed an 82.3% rate of neurologic symptoms among 509 hospitalized COVID-19 patients in Chicago area. SARS-CoV-2, the virus that causes COVID-19, appears unique among coronaviruses for its ability to cause multi-organ disease, including affecting brain and nervous system. Neurologic symptoms were present at COVID-19 onset in 215 patients (42.2%), at hospital admission in 319 patients (62.7%), and at any time during the course of the disease in 419 patients (82.3%). The most frequent neurologic symptoms were myalgias (muscle aches), headaches, encephalopathy, dizziness, and loss of taste and smell. The study authors found no significant differences in functional outcome or mortality at discharge for patients experiencing neurologic symptoms with the exception of encephalopathy patients, who showed lower functional outcomes and greater likelihood of death 30 days after.

Long-term Health Consequences of COVID-19: The clinical spectrum of SARS-CoV-2 infection ranges from asymptomatic infection to life-threatening and fatal disease. Current estimates are that approximately 20 million people globally have “recovered”. However, clinicians are observing and reading reports of patients with persistent severe symptoms and even substantial end-organ dysfunction after SARS-CoV-2 infection. Because COVID-19 is a novel disease, the long-term clinical effects of the disease remains uncertain.

Mitigation / Suppression:

WHO: 10% of world’s people may have been infected: On Monday, the head of emergencies at the WHO said the agency’s “best estimates” indicate roughly 1 in 10 people worldwide may have been infected by the coronavirus. This is more than 20 times the number of confirmed cases. He stated the disease continues to spread and cases increasing – he warned of a difficult period ahead. Dr. Ryan said southeast Asia, Europe and the eastern Mediterranean were seeing an increase, while the situations in Africa and the Western Pacific were slightly better. Overall, though, the world is heading into a difficult period.

Multisystem inflammatory syndrome in adults: Multisystem inflammatory syndrome in children (MIS-C), is a rare, severe complication of COVID-19 infection in children. Researchers published an analysis of 27 adult patients determined to have a related condition, MIS-A. The patients had cardiovascular, gastrointestinal, dermatologic and neurological symptoms without severe respiratory presentation, similar to what has been observed in children experiencing MIS-C. Notably, 8 of the 27 patients included in this study did not have any documented positive COVID-19 diagnostic test, although all had positive serological tests. Further study is needed to better understand MIS-A, including whether it is associated with acute COVID-19 disease or if it is exclusively a post-acute syndrome.

Women more likely to embrace mitigation behaviors: A behavioral report detailed the findings of three studies showing gender differences in pandemic-related mitigation behavior during the peak period of the pandemic in the US. The report included an 800-participant survey of public health behaviors, an observational study of mask wearing among 300 pedestrians, and a county-level analysis of 15 million anonymized cell phone coordinates. The study found a greater proportion of mask wearing among women pedestrians (57.7%) than men (42.3%) in New York City, New Haven, CT, and New Brunswick, NJ. Nationwide cell phone coordinates showed men practicing comparatively less physical distancing than women from Mar 9 to May 29 as measured by movement and visits to nonessential retailers. The findings are consistent with pre-pandemic health-care behaviors, the study's authors note. Researchers conclude that fine-tuning health messages to alert men in particular to the critical role of maintaining social distancing, hygiene, and mask wearing may be an effective strategy to reduce COVID-19 spread.

Incidence of COVID-19 in young adults: Last week, US CDC’s MMWR published a study describing trends in COVID-19 transmission among young adults, including college and university students. COVID-19 cases among young adults increased by 55% during August and early September, with the greatest increases in the Northeast and Midwest regions. Incidence among non-Hispanic White young adults increased by nearly 150% from August 2 to September (and even higher in the Midwest and Northeast), while incidence among racial and ethnic minorities remained steady or decreased over that time. The researchers hypothesize the uptick is likely related to students returning to school; however, there are likely a myriad of factors that require further investigation.


A Call for Diagnostic Tests to Report Viral Load: Scientists and public health experts are highlighting  new research indicating that cycle threshold CT values could help doctors flag patients at high risk for serious disease. Cycle threshold indicates how much virus an infected person harbors. Recent findings suggest the numbers could help officials determine who is infectious and should therefore be isolated and have their contacts tracked down. CT value is an imperfect measure, but whether to add it to test results is one of the most pressing current debates.

COVID-19 and Psychological Distress during NY lockdown: On Monday, a study analyzing trends in internet searches found increased queries for anxiety, panic attack, and insomnia during the New York statewide lockdown in March. Researchers looked at trends in internet searches for mental health concerns from Mar 22 to May 15. They used anonymous, publicly available Google Trends to compare search volumes for specific mental health terms with expected volumes based on historical search data. Relative search volumes (RSV) were calculated for each week of the lockdown.  Searches for anxiety increased significantly and RSVs remained an average of 18% higher than expected for three consecutive weeks following the Mar 22 lockdown order [5% to 29%]. RSVs for panic attack soared during the first week of lockdown [37% to 97%] and remained at higher-than-expected levels for 5 consecutive weeks, while searches for insomnia were 21% higher than expected [1% to 55%] during the study period.

WHO mental health survey: On Monday, the WHO released the results of a survey describing the impact of COVID-19 on “mental, neurological, and substance use services” in 130 countries. Notably, the pandemic has disrupted or halted critical mental health services in 93% of countries worldwide while the demand is critically increasing. Conspicuously, 93% of countries surveyed faced disruption or suspension of critical mental health services due to the pandemic with outpatient care being most affected. One-third of countries responding noted disruption in at least 75% of these services. Among responding countries, 35% reported disruption in emergency or life-saving services, and 30% experienced disruption in supply of medicines for conditions related to mental, neurological, or substance use disorders. The findings come in advance of WHO’s virtual event on October 10th which is World Mental Health Day.

The Work From Home WorkSTEPS Medical Team:

Ben Hoffman, MD, MPH
Chief Medical Officer

Tony Nigliazzo, MD
Medical Director

Loraine Kanyare, MSN, MPH, RN
Director of Case Management

Robert L. Levitin, MD
Physician Consultant

Lynda Phillips, LVN
Nurse Case Manager

Codey Church, LVN
Nurse Case Manager

Kerry Womack, LVN
Nurse Case Manager

Chuck Reynolds
Strategic Communications Consultant

This Guidance (“Guidance”) is provided for informational and educational purposes only. It is not intended as Legal Advice or Medical Advice. Adherence to any recommendations included in this Guidance will not ensure successful diagnosis or treatment in every situation. Furthermore, the recommendations contained in this Guidance should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care nor exclusive of other methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific therapy must be made by the physician and the patient in light of all the circumstances presented by the individual patient, and the known variability and biological behavior of the medical condition. Similarly, this Guidance is based on current advice, comments, and guidance from the EEOC, CDC and the CMS made publicly available. The ultimate judgement regarding the propriety of any specific employment action must be made by the company and attorney in light of all of the circumstances presented by the company, state and federal rules existing at the time and the then current state of the National Pandemic. This Guidance and its conclusions and recommendations reflect the best available information at the time the Guidance was prepared. The results of future studies or changes in rules, regulations or laws may require revisions to the recommendations in this Guidance to reflect new data. WorkSTEPS does not warrant the accuracy or completeness of the Guidance and assumes no responsibility for any injury or damage to persons or property arising out of or related to any use of this Guidance or for any errors or omissions.

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Newsletter written by WorkSTEPS CMO Dr. Ben Hoffman and WorkSTEPS’ expert medical team.