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Declaration of Dr. Marc Lipsitch and Emma Accorsi regarding Oregon Temporary rule 437-001-0749

Oregon’s Occupational Health and Safety Administration (OR OSHA) regulates farmworkers’ working and housing conditions, including conditions in approximately 330 employer-owned labor housing sites in the state. With the spread of COVID-19, OR OSHA issued temporary COVID-19 standards for agriculture that went into effect on June 1, 2020. 

Although the temporary standards included other COVID-19 precautions for labor housing, transportation, and field sanitation, they critically did not increase the required living space per person in labor housing from previous levels of 40 or 50 square feet per person. Instead the standards mandated that: (1) “beds and cots must be spaced at least six feet apart between frames in all directions and arranged so that occupants sleep head to toe” or (2) “beds and cots must be separated by a bed length, floor to near ceiling temporary non-permeable barrier (for example, using plexiglass, heavy plastic, lightweight wood sheeting, etc.) placed perpendicular to wall such that a 28-inch minimum aisle remains available to the occupant of each bed” or (3) “an operator may implement other effective engineering and/or administrative controls to modify this requirement with prior approval by Oregon OSHA.”

The statement below was written in response to the risk that continued crowding poses to farmworkers residing in employer-owned labor housing, and the application of the six-foot social distancing rule to a situation with extended indoor contact. This statement was written by Emma Accorsi (eaccorsi@g.harvard.edu) and Dr. Marc Lipsitch (mlipsitc@hsph.harvard.edu) of the Harvard T.H. Chan School of Public Health Center for Communicable Disease Dynamics and submitted to Nargess Shadbeh of the Oregon Law Center on May 5, 2020.

Recent outbreaks show that COVID-19 spreads rapidly and uncontrollably in densely populated congregate settings, such as cruise ships, nursing homes, prisons and jails, group homes, and meat-packing plants. Migrant workers, including farm workers, living in crowded, poorly ventilated temporary housing are at high risk for coronavirus infection. When infected, migrant workers are more likely to experience severe outcomes, including mortality, due to limited access to healthcare and a higher burden of comorbid conditions. Singapore was an early model for control of the coronavirus pandemic, but has since experienced a large growth in cases due to spread among migrant workers. As of April 28th, 12,694 of 14,951 (84.9%) total coronavirus cases in Singapore were among migrant workers residing in dormitories1. Closer to Oregon, 53 of 71 migrant farm workers were recently found to be positive for COVID-19 at a Stemilt labor camp in East Wenatchee, Washington.

Given the transmissibility of the SARS-CoV-2 virus and the fact that it is a novel pathogen for which aspects of transmission are still not well-understood, it is our expert opinion that the Temporary rule issued by the OR OSHA on April 28, 2020 does not go far enough to protect the health of farm workers residing in employer-owned housing. More specifically:

  1. The Centers for Disease Control and Prevention (CDC) continues to emphasize the importance of social distancing to reduce SARS-CoV-2 transmission; however, workers provided with 40 or 50 square feet of living space per person under OR OSHA’s current rules cannot successfully social distance. They will inevitably come into close contact with each other in this crowded space and touch many of the same surfaces, on which SARS-CoV-2 can remain for up to 72 hours2. This virus is transmitted very effectively through the types of close contacts that occur within a household. Even in more spacious settings, studies have found between 10.5% to 16.3% of household members of COVID-19 cases became infected3–5.
  2. Similarly, the six-foot social distancing rule recommended by the CDC is based on the average distance that large respiratory droplets travel before settling out of the air due to gravity, and is intended for brief contact occurring between people who are outside their homes for essential activities. Six feet does not provide total protection from infection, and infection risk increases with the amount of time exposed. Confined sleeping quarters are associated with outbreaks of respiratory diseases in military and other settings. Therefore, the six-foot social distancing rule for incidental contact cannot and should not be interpreted to mean that it is safe for migrant farm workers to sleep for extended periods of time at a distance of six feet from each other.
  3. This high density housing will facilitate transmission between workers who do not know they are infected and those who reside with them. Many infected individuals initially do not have symptoms. For example, among the migrant farm workers at the Stemilt labor camp, 41 of the 53 infected individuals were asymptomatic at the time of testing. However, research suggests that individuals can be infectious for one to six days before developing symptoms6. Since SARS-CoV-2 is highly transmissible, and it takes time for cases to develop symptoms, and further time to perform diagnostic tests for symptomatic individuals, spread in crowded spaces can remain undetected until it has grown out of control. Therefore, it is critically important that strong actions to control transmission within employer-owned housing by reducing density are taken as early as possible, even if there are no identified COVID-19 cases yet.
  4. SARS-CoV-2 is a novel pathogen, and scientists do not yet fully understand how it is transmitted, therefore OR OSHA rules should ensure migrant worker safety under all plausible routes of transmission. It is unknown whether SARS-CoV-2 can spread through aerosols, which are small exhaled respiratory droplets that can remain suspended in the air for longer periods of time and travel further than six feet in air currents. A number of studies have identified viral RNA in air samples taken at varying distances from hospitalized patients7,8, and also in crowded public areas8. One study that aerosolized the virus under idealized laboratory conditions suggested that it remained infectious after three hours2. Under aerosol transmission, infections could possibly occur at a distance of greater than six feet, and despite barriers (due to the opening at the top and other room air flow). In this scenario, the most advantageous interventions would be to de-densify the space, and dilute the infectious aerosols in the room by bringing in more fresh outdoor air9. However, given that workers are not consistently able to open their windows because of night-time pesticide application, resources should be invested in de-densifying housing units to protect against possible aerosol transmission.
  5. Crowding is known to be associated with infectious and respiratory disease risk. In one study of college students residing in dorms, an increase of 100 square feet of dorm space was associated with 10.8 fewer upper respiratory infections per 100 students per academic year10. To this end, we recommend decreasing occupancy to no more than two unrelated individuals for a room of 200 square feet with the exception of family traveling together. This has the dual-advantage of allowing for more space between people, and reducing the overall number of individuals contacted by each person. Furthermore, we discourage the rooming of unrelated individuals together, unless they recently lived or traveled together prior to arrival, as this could allow for transmission between individuals who might otherwise not come into extended contact with each other.

 

References:

  1. Leung, H. Virus Outbreak Among Singapore’s Migrants Serves as Warning. Time (2020).
  2. van Doremalen, N. et al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. N. Engl. J. Med. 382, 1564–1567 (2020).
  3. Bi, Q. et al. Epidemiology and transmission of COVID-19 in 391 cases and 1286 of their close contacts in Shenzhen, China: a retrospective cohort study. Lancet Infect. Dis. (2020) doi:10.1016/S1473-3099(20)30287-5.
  4. Burke, R. M. et al. Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 – United States, January-February 2020. MMWR Morb. Mortal. Wkly. Rep. 69, 245–246 (2020).
  5. Li, W. et al. The characteristics of household transmission of COVID-19. Clin. Infect. Dis. (2020) doi:10.1093/cid/ciaa450.
  6. Arons, M. M. et al. Presymptomatic SARS-CoV-2 Infections and Transmission in a Skilled Nursing Facility. N. Engl. J. Med. (2020) doi:10.1056/NEJMoa2008457.
  7. Santarpia, J. L. et al. Transmission Potential of SARS-CoV-2 in Viral Shedding Observed at the University of Nebraska Medical Center. medRxiv (2020) doi:10.1101/2020.03.23.20039446.
  8. Liu, Y. et al. Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. Nature (2020) doi:10.1038/s41586-020-2271-3.
  9. Morawska, L. & Cao, J. Airborne transmission of SARS-CoV-2: The world should face the reality. Environ. Int. 139, 105730 (2020).
  10. Cedeno Laurent, J. G., Allen, J. G., McNeely, E., Dominici, F. & Spengler, J. D. Influence of the residential environment on undergraduate students’ health. J. Expo. Sci. Environ. Epidemiol. 30, 320–327 (2020).
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