7/16/20 COVID-19 Brief: The Air We Breathe – Implications of Aerosol Transmission

It isn’t news that HVAC systems should be part of a company’s comprehensive prevention and Return-To-Work strategy. However, as evidence from contact tracing studies has improved our understanding of virus transmission, the role of air circulation has emerged as increasingly important.

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

The Air We Breathe – Implications of Aerosol Transmission

Late last week, the World Health Organization issued an updated scientific brief on the transmission of SARS-CoV-2. In the update, they acknowledged: “Short-range aerosol transmission, particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons cannot be ruled out.”

The backstory behind the WHO’s decision to recognize the possibility of aerosol transmission without giving a full-throated endorsement of the idea is well-presented in this article in Vox. It is a worthwhile read, and important for policymakers to understand (at least at a high level).

More important, and certainly more urgent, is the question: “So what?” Does the increased recognition of airborne transmission of COVID-19 imply that we should be doing anything new or different than we have been doing to protect our employees and customers?

Maybe. It depends on how much attention you’ve paid to ventilation as part of your COVID-19 prevention strategy.

HVAC Matters

It isn’t news that HVAC systems should be part of a company’s comprehensive prevention and RTW strategy. In fact, we noted it as a key measure a number of times, including in this May 22nd article. However, as evidence from contact tracing studies has improved our understanding of virus transmission, the role of air circulation has emerged as increasingly important.

This article with excellent graphics does the best job I’ve seen at connecting the dots between: A) lessons learned from contact tracing; B) the role of air circulation in disease transmission; and C) practical changes focused on air circulation as well as distancing, masking and sanitation to reduce disease transmission.

Implications for Your Business

Perhaps because ventilation hasn’t received as much attention as things like working from home, distancing, sanitation and mask-wearing, many businesses have yet to focus seriously on HVAC system adjustments and upgrades. Here are some steps and resources to consider:

1. At each site, assemble a team that will be led by the COVID-19 Site Leader and include members from operations and facilities/engineering. I recommend members review the McKinsey & Company report Can HVAC systems help prevent transmission of COVID-19? to help prepare them for their role on the team.

2. Have facilities/engineering evaluate existing HVAC systems and settings in relation to recommended practices and report back on status, issues, possible solutions and costs.

3. Conduct a comprehensive walk-through of your facilities, looking for:

  • Enclosed spaces with inadequate ventilation/air exchange (e.g., interior conference rooms, lunchrooms, break rooms, locker rooms)
  • Areas where air is flowing across the room, potentially pushing infected particles from employee to employee
  • Areas where ventilation is good because of existing air exchange systems and/or windows/doors that enable fresh air exchange.

4. Based on the facilities/engineering report and walk-through, prioritize and identify actions to reduce infection risk by adjusting or updating HVAC systems, installing air filtration units such as this, manufactured by Carrier, limiting access to high-risk spaces, encouraging/enabling access to low-risk spaces, and other measures.

Adapting to New Information

Having to monitor and adapt to new information about COVID-19 can be exhausting, but it must be done. The good news is that researchers are helping us better understand how SARS-CoV-19 spreads, and that’s enabling companies make their COVID-19 prevention and RTW strategies more effective and more efficient.

Based on the feedback we’ve been receiving about this Brief, we’re doing a good job helping readers understand and adapt to information that matters. If you have suggestions about how we can improve or topics you’d like us to address, please let us know.

Finally, from consulting guidance, to testing, to contact tracing, there are many ways WorkSTEPS can support your organization’s prevention and RTW efforts. Learn more here.  

Ben Hoffman, MD, MPH
Chief Medical Officer, WorkSTEPS

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


Area Reported Cases Deaths Recovered
Global 13,560,323 583,521 7,913,764
United States 3,569,568 139,504 1,601,508

Share of daily new cases reported by each US region:


States set daily records:  

As states continue to set records with daily case counts; related fatalities due to coronavirus are beginning to creep up. Arizona, Texas, Mississippi, California, and Florida all breaking records for average daily fatalities over the past 7 days. The state hardest hit may now be Florida, which set a record this past weekend with 15,300 new cases confirmed on Sunday. In Houston, uncontrolled spread led Mayor Sylvester Turner to call for a 2-week resumption of restrictions to decrease the steep hospitalization curve. Governors in 23 states have now ordered the mandatory wearing of face masks or coverings in public.

Around the globe:

Countries that had flattened their curves are detecting and responding to new flare-ups. Hong Kong is currently battling its third wave and has tightened social distancing again in response to an uptick. In Australia, the Melbourne area is under new restrictions due to case resurgence.

Arthritis drug may lower fatalities in severely ill:

Two new studies published showed that rheumatoid arthritis drug Tocilizumab is associated with lowered death rates in coronavirus patients on mechanical ventilation. Tocilizumab blocks interleukin-6 (IL-6), a protein involved in  "cytokine storm" that can lead to respiratory failure in severely ill patients. In the first observational study, researchers compared 78 patients who received the drug to 76 who did not. They found that tocilizumab was linked to a 45% reduction in risk of death and improved status. In the second study, researchers in Italy found tocilizumab reduced patient fatality rates by fifty percent compared with standard care but lengthened hospital stays.


FDA expanded list of hand sanitizers to avoid:

The FDA now lists a chart of 59 varieties of hand sanitizer that should be avoided. All of the products in the FDA's latest methanol update appear to originate in Mexico. Per the FDA most of the  products that are labeled to contain ethanol (also known as ethyl alcohol) but that have tested positive for methanol - a toxic substance when absorbed through skin or ingested.

TB vaccine (BCG) may offer protection in severe patients:

On Thursday, researchers reported a tuberculosis vaccine - bacillus Calmette−Guérin (BCG) routinely given to children in countries with high rates of that bacterial disease might be helping to reduce deaths from COVID-19. After adjusting for factors that might affect vulnerability to the virus - such as income, education, access to health, and age, researchers found that countries with higher rates of the vaccination for tuberculosis had lower peak mortality rates from coronavirus. The BCG vaccine is currently being tested for preventing COVID-19 in healthcare workers.

COVID-19 lingering effects:

On Thursday, researchers from Rome reported that severe COVID-19 has lingering after-effects. Nearly 90% of recovering COVID-19 patients discharged from a hospital in Rome reported not being back to normal an average two months after initial illness. The study included  143 adults, most of whom had been diagnosed with pneumonia, and one in five had needed help to breathe. An average of 60 days after their first coronavirus symptoms, 87.4% still reported at least one symptom, fatigue and shortness of breath, and  55% had three or more residual symptoms. About one in four still had joint pain, and about one in five had chest pain. Roughly 44% said their quality of life was worse now than before they got sick.  

WHO acknowledged coronavirus can be airborne:

In an open letter to the WHO last week, 239 scientists cited mounting evidence that in crowded indoor spaces, the virus can stay aloft for hours and infect others. Dr. Benedetta Allegranzi, head of the agency’s infection prevention and control committee, said on Tuesday that the possibility of airborne spread in “crowded, closed, poorly ventilated settings” could not be ruled out. The agency is working on a scientific brief summarizing the current knowledge around transmission of the deadly virus, which should be available in the coming weeks.


Lessons learned from the universities may be applied to corporate reopening strategies:

Yale and Harvard Schools of Public Health have produced a highly effective COVID-19 screening model to usher in the safe reopening of colleges and universities. Their research suggests combining basic prevention measures such as hand washing, behavioral interventions, and a low sensitivity high specificity test performed every 2-3 days will control outbreaks at a justifiable cost. This would allow campuses to safely reopen in the fall.


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.