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WHN Science Communications

Open Letter on SARS-CoV-2 Mitigation Strategies

  • Keywords:
  • Mitigation Strategies
  • Publication date:

    Submission date:


    From the time when it was first widely recognized as a public health danger in January 2020, to the present, SARS-COVID19 has infected almost 90,000,000 people worldwide, it has killed almost 2 million people with the largest concentration of those deaths in the United States. Almost 50 million people have recovered but a noticeable number suffer from months-long debilitating conditions and a documented but yet-to-be-fully-quantifiable number of patients, including young individuals who recovered from mild infections, have what appear to be long-term damage to major body organs, such as the lungs and the heart. This has happened despite intensive calls from public health experts for enforced mitigation actions. And it is now clear that the virus has adapted to be more contagious; with a strand from the United Kingdom (B117) causing major disruption in the UK and in Ireland. This new variant is highly infectious in adults and children, is now seeded inside the United States. and will present unique challenges for schools and for other business establishments who are concerned with public health.

    The undersigned believe that many of the interventions utilized during the pandemic to mitigate against the spread of SARS-CoV-2 prior to December may no longer be sufficient to cope with the new variant (as well as the variants from South Africa and Brazil.) For that reason, we believe that the best approach to handling the virus until there is widespread vaccination would be to conduct school fully remotely and to offer only curb-side pickup and no-contact. That said, if indoor activity cannot be avoided, the interventions that have been suggested before the pandemic must now be treated as imperatives. And the interventions must be specifically calibrated to maximize mitigation. Professional and public health organizations are often slow to adapt and reluctant to give specific and solid guidance. This letter is meant to rectify that problem. Below are nine imperatives that MUST be honored if you and your institutions want to maximize the safety of students, staff and/or customers. If you cannot honor them, it is our strongest recommendation that you do not hold any indoor activities that require anything but very brief human interactions indoors.

    • Especially when indoors, masking must be universal and diligently enforced. Masks must cover the nose and the mouth and fit snugly around one’s face; they should be either N95 (or KN95) masks, 3-layer surgical masks,or 2-layer cotton-pleated style masks with a filter insert; if other fabrics are used they should be doubled up around the nose/mouth/face; strongly consider using nose clips to enhance the masks. Strongly suggest a doubled surgical + cloth mask which has been found to offer considerable protection just short of less-widely available N95 masks.
    • Take advantage of any opportunity to draw in fresh outdoor air (opening windows) or move activities outdoors including restaurant service and teaching; if excessive cold is an issue encourage (or provide) outdoor winter clothing and outdoor heaters; do not create “igloos” outside — they function as indoor spaces because they simulate the problems with indoor spaces
    • Deploy portable HEPA air cleaners calibrated to achieve a minimum of at least 4 and ideally up to 6 Air-Changes-Per Hour in every enclosed space including classrooms and bathrooms; this requires that each air cleaner have the appropriate Clean-Air-Delivery-Rate, abbreviated as CADR, for the room volume and that can be determined through one of many free, online applications; a typical K12 classroom would probably have a CADR of 500-800 (cfm). Cheap and easy to make do-it-yourself versions of portable cleaners can also be used but the CADR still must be assessed and ensured. More than one cleaner, if they are insufficient as an individual device, should be used in the same room to achieve the desired ACH.
    • Monitor and maintain a relative humidity of 40-60% and deploy, at least in winter, humidifiers, calibrated to room sizes, if this range is difficult to maintain naturally. Monitor visually for any development of damp spots and adjust the humidity or ventilate accordingly.
    • Carefully and consistently monitor the indoor-air-quality of your spaces and rooms, through carbon-dioxide monitors (which helps approximate the outdoor air-changes-per-hour) and hygrometers (that measure humidity); CO2 should consistently fall below 800 parts-per-million (ppm) and even lower is better; relative humidity should be between 40-60%. For the purposes of relevance and accuracy, these measures should be taken only after rooms have been occupied by people for prolonged periods. Interventions described above should help to reach these metrics.
    • Maximize spacing between individuals as much as possible and reduce occupancy; diligently monitor and maintain that distancing (6ft is the most cited figure.) Note: spacing of any distance is no guarantee of protection in indoor spaces due to aerosolization of the virus.
    • Whenever possible, maintain cohorts of students in classrooms so that if an exposure is documented, targeted quarantining is possible, and allows for contract tracing.
    • Advertise, through clear signage, the most common symptoms associated with COVID19, notably cold-like symptoms and a loss of taste and/or smell, and discourage anyone who exhibits those symptoms from coming into indoor spaces until they are tested and the conditions are resolved; whenever feasible, survey potential occupants to see if they have visited high-risk areas or mingled with potentially-infected persons and discourage said people from entering your indoor space. Testing should be done 3-14 day’s post exposure.
    • Handwashing materials should be plentiful and easily accessible, individualized as much as possible to avoid close contact with other individuals; have laminated signs showing the WHO/CDC handwashing method in easy visual distance of the sanitation materials; encourage frequent hand washing.

    As we stated at the beginning the right action now is to move schools to online learning and restaurants to pick up only. Where indoor activities are essential these guidelines can make them safer.

    DISCLAIMER:  None of the undersigned nor any individual associated with this letter is responsible for the implementation (or lack of implementation) of any of the above-described interventions, imperatives or suggestions.


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