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Diving in the Era of COVID-19




The following is an article written by Dr. Douglas Ebersole - physician, technical dive instructor, and a recovered COVID-19 patient. As a medical advisor to the training agency RAID, he was asked to write an article about this latest epidemic. Dr. Ebersole's unique perspective provides for an interesting and informative read on COVID-19 and how it relates to scuba diving. It has been shared with permission from the author.


I come to you as a recreational and technical diving instructor, as a physician consultant for Divers Alert Network, and as a COVID-19 survivor. For me, was just an occupational hazard. I tested positive for COVID-19 after seeing a patient in my cardiology clinic for an unrelated condition who seemed quite short of breath. He was admitted to the ICU and tested positive for COVID-19. Thankfully, he did not require a ventilator and recovered after approximately two weeks in the hospital. I was notified of his positive test one week after my exposure.  As I had been wearing my N95 mask when I saw him, I was advised to take my temperature daily and self monitor for symptoms. I did well for a few days and then began developing a cough and profound fatigue followed by fever. I ended up testing positive and spent the next couple of weeks quarantined at home. I have now recovered and will be going back to work this week and look forward to returning to diving. More on that later. I am definitely one of the lucky ones. Thousands of others have been hospitalized, required ventilators, and have died. Our thoughts and prayers should go out to those patients and their families.


While this is a horrific global event, the diving industry will come out the other side. When we do, how do we safely get people diving? This is a multifactorial issue, involving dive shops, dive charters, instructors, and the individual diver/student.

Background


The novel coronavirus, known as SARS-CoV-2, is the cause of the disease COVID-19 which has killed almost 200,000 people worldwide as of today (April 25, 2020). SARS-COvV-2 is part of the viral group known as “corona” (Latin for “crown” or “halo”) because of the pattern of proteins that stud its surface. Coronaviruses are responsible for 15-30% of acute respiratory infections each year. Human to human spread of the virus is by way of large respiratory droplets (coughing, sneezing, speaking) and touching contaminated surfaces. The incubation period of the virus is 2-14 days with a mean of 5.1 days.


Medical experts believe a vaccine for COVID-19 is still at least 18 months away. Until a vaccine is available or effective therapies are found, the disease will continue to spread. The impact of social distancing and “flattening the curve” has been helping keep people safe and helping to avoid overwhelming our medical resources, but it has also had a massive economic impact on society. This impact has been felt especially severe in the diving industry as it is based on discretionary spending by consumers. Additionally, for many divers, their interest in diving is strongly linked to the ability to travel internationally. Until travel restrictions are lifted and consumers are confident in the ability of the airlines and cruise industry to keep them safe, the dive industry will likely continue to suffer economically. But enough doom and gloom. What can we do as a community to help the dive industry?

Dive Centers


The diver or dive student needs to feel safe before they will go into a store to purchase gear or training, to board a dive charter, or simply to go diving. For the foreseeable future, this is going to mean wearing masks in public, social distancing in dive shops, fewer passengers spread out on dive charters, an emphasis on online training where possible, and smaller class sizes, again to allow students to practice social distancing. Pay by phone or curbside tank drop off could also be effective interventions to reduce the chance of infection.


One positive aspect of this pandemic is it has forced dive shops and training agencies to move towards more online training. E-learning has been growing in popularity for some time and has been embraced by various training agencies and dive centers to greater and lesser degrees. RAID now allows students access to all of their training materials from open water diver through cave diving instructor at no cost. Other training agencies have also moved towards offering certain courses at low or no cost to students in an attempt to keep money flowing into the dive centers during this very difficult time.

Webinars and Zoom conferences have become the new normal. There have been a number of outstanding live conferences put on by The Diver Medic, Dirty Dozen Expeditions, Dive Ninjas, Deeper Discussions and Shallow Thoughts, Divesoft Talk Live, and many others these past few weeks. I imagine dive centers will incorporate this mode of education into some aspects of their academic courses in the future.


Unfortunately, many dive centers will not be able to financially weather this storm, but as a community we need to do everything we can to help support our local dive centers. Take this time out of the water to get your gear serviced. For dive centers not located in diving hotspots like Florida or California, it is going to be really tough until travel restrictions are lifted and their customers feel comfortable getting on an airplane. If you have a trip that is in jeopardy, consider rescheduling rather than cancelling and asking for a refund. Buy gear in preparation for upcoming dive trips in advance of the quarantines and shelter in place orders being lifted. Sign up for continuing education and do the academic portions online or via a conferencing app with your instructor. Every little bit helps. We are all in this together.

Gear Cleaning


Rinsing off dive gear at the end of each pool session will no longer suffice. We need to truly disinfect any items that could be shared among divers, especially regulators and BCDs.


Divers Alert Network (DAN) has recently published guidelines regarding disinfecting scuba gear. The link is here:


https://www.diversalertnetwork.org/emailview/landing/coronavirus/gearDisinfection/index.html


Coronaviruses belong to a group of enveloped viruses, which means the virion (the form that the virus takes while outside the host cell) is protected by an oily lipid layer. As with most enveloped viruses, damaging or destroying this lipid layer will inactivate the virus. Studies of other coronaviruses have shown their infectivity can be reduced by heat, UV light and alkaline or acidic conditions. Because of this, and the fact that enveloped viruses are generally easily inactivated, surfaces can be disinfected using household cleaning products.


Because research into SARS-CoV-2 is ongoing, there is debate about how long it can survive on surfaces. Recent studies have shown that it can survive up to 3 hours in an aerosol droplet (such as from a sneeze), 4 hours on copper, 24 hours on cardboard, and 2-3 days on plastic and stainless steel. In water, however, it is unclear how long SARS-CoV-2 survives. Studies on the SARS virus, called SARS-CoV-1 and the cause of an epidemic in 2003, have shown that it remained infectious for long periods in surface water (lakes, rivers, wetlands, etc.) and previously pasteurized sewage at both low and ambient temperatures. In chlorinated or bromated pools and hot tubs, the CDC specifies that SARS-CoV-2 would be inactivated.



Heat

There is very little data on SARS-CoV-2, and much of it is preliminary. In times like these scientists will look to related but slightly harder-to-kill viruses. In the case of the novel coronavirus, some data reports are based on the SARS-CoV-1 virus because it is more difficult to kill than the novel coronavirus. One study found that the SARS-CoV-1 virus loses infectivity after being heated to 133°F (56°C) for 15 minutes, and the World Health Organization specifies this temperature and timing as well . Another study found that the SARS-CoV-1 virus remains stable between 40°F (4°C) and 98°F (37°C) and would lose infectivity after 30 minutes at 133°F (56°C)

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Divers Alert Network has received questions about the virus entering a scuba cylinder as a result of contaminated air being drawn into the compressor. During the process of compressing air, using the ideal gas equation T2 = T1 x (P2/P1)(n-1)/n we can calculate that a four-stage compressor with 1 ATA inlet pressure and an 80°F environment pumping air up to 29 ATA or around 4000 psi, would have an inter-stage temperature inside the cylinder of 224 °F. This calculation is very basic and does not account for anything outside of ideal conditions. However, it does indicate the instantaneous temperature at the moment of peak pressure.


In reality, the outlet valve temperature will likely be 170°F-190°F, and the gas temperature around 150°F, occurring during each stage of the compressor (i.e. four cycles for a four-stage compressor assuming each stage’s outlet temperature is the same). Because this is definitively hot enough to kill SARS-CoV-2, it is therefore unlikely that COVID-19 would survive this process should an infected individual cough into the compressor intake. It is important to note that infected droplets exhaled by a person can be as small as 0.5 micron; the filter systems alone would not remove these, but the virus should be dead at that stage.  


It should be noted, however, that if an individual carried the virus on their hands, either as a result of being infected or unknowingly touching an infected surface, and touches the cylinder valve or fill whip, the virus could potentially enter the cylinder through this route. It has been shown that some viruses are extremely pressure resistant — an order of magnitude above diving gas storage pressures. These studies, however, were conducted on noroviruses, a non-enveloped group of viruses that are generally harder to kill than enveloped viruses. Other studies conducted on enveloped viruses such as the flu only explored the efficacy of high hydrostatic pressure at 289.6 MPa (42,003 PSI) . It is therefore very important to practice hand washing and disinfection of high-touch areas including cylinders and fill stations, as it is likely that a virus could survive at diving gas storage pressures.

EPA Guidelines

No matter the active ingredient or method of disinfecting scuba equipment, proven efficacy against the novel coronavirus is of utmost importance. The EPA’s “List N” is a compilation of products that have proven efficacy against SARS-CoV-1 and will therefore also work to kill SARS-CoV-2. Outside of the United States, local governing bodies may also have registered disinfectants. Following the directions for use for each individual product will ensure its efficacy.


When product manufacturers register their products with the EPA, they must submit a list of uses for the product. It is uncommon for registered products on List N to contain “scuba”; more likely to be listed are respirators or materials that scuba equipment is made of. When choosing a disinfectant solution from List N it is important to check that the product’s EPA registration specifies its use for the materials in question. Some products commonly recommended by underwater breathing equipment manufacturers are classified as quaternary ammonium sanitizers registered with the EPA for use in food service only and are not currently on the EPA’s List N. The EPA does not consider them to be effective against SARS-CoV-2 when applied on those materials and surfaces. 

Quaternary Ammonium Compounds

Quaternary ammonium compounds, or quats, are a group of chemicals that are exceedingly common as active ingredients in cleaning solutions. These agents are hydrophobic and as such are effective against enveloped viruses. Quats are thought to react with the viral envelope and “disorganize” it, leading to the contents of the virus leaking out and degrading. In addition, little evidence exists to support viral resistance against these compounds. Studies have shown that quats are effective against SARS-CoV-1, and the World Health Organization (WHO) recommends the use of cleaning products containing these compounds in their laboratory biosafety guidance related to coronavirus disease 2019.

Simple Green has been shown to be effective against viruses similar to SARS-CoV-2 when used in accordance to its directions for use


While not on the List N , another agent that has been shown to be effective against SARS-CoV-1 is MadaCide-1. It’s labeling states that it is effective against the SARS-CoV-1 virus if used with a contact time of two minutes and other viruses such as Hepatitis B and Hepatitis C with five minutes of contact time.


While Steramine is an effective sanitizing product, and some manufacturers recommend it for use on dive gear, it does not appear on the EPA's "List N" and is thus not endorsed for removal of the new coronavirus.

Bleach

When using bleach, the use of gloves, a mask, and eye protection is encouraged. Mix the solutions in well-ventilated areas, and use cold water, as hot water will decompose the active ingredient. It is important to never mix bleach with other chemicals and to remove all organic matter from items to be disinfected, as this too will inactivate the active ingredient. Items disinfected with bleach must be thoroughly rinsed with fresh water and allowed to dry before use, as it is corrosive to stainless steel (in higher concentrations) and irritating to mucous membranes, skin and eyes. Highly concentrated bleach solutions have also been found to be harmful to life-support equipment, causing metal fatigue and in some cases hose failure during the Hart building anthrax attack. As such these solutions are not used by EPA units for dive equipment when effective alternatives exist.



Soap and Water

Washing hands and surfaces with soap and water is one of the most effective ways to protect against the virus. The type of soap used is not important. Washing with soap and water does not kill microorganisms but physically removes them from a surface. Running water by itself can be effective in removing some unwanted material from surfaces, however, soap will physically pull material from the skin and into the water. Divers Alert Network was asked why soap and water will not work for scuba equipment if it is recommended for hands. Soap and water, as stated above, must be combined with mechanical action to be completely effective. Soaking scuba equipment in soapy water alone is not an effective disinfection method. If soapy water was combined with mechanical action, it would theoretically prove to be more efficient. However, there are some parts of scuba equipment that are not easily reached without disassembly, such as the inside of a regulator. Since an exhaled breath will travel through the inside of a regulator and make contact with the diaphragm, lever arm, and other internal surfaces, soaking the regulator in a disinfectant solution may be a better option.

Best Practices

When selecting a disinfectant, it is of utmost importance to use a product that has proven efficacy against either SARS-CoV-2 or the harder-to-kill SARS-CoV-1. Consult your local governing body’s pesticide registration system for its list of registered disinfectants if the products specified in the EPA’s List N are unavailable in your area. When using these products, be sure to follow the directions and use the specified personal protective equipment (such as gloves or eye protection) when disinfecting. If registered products cannot be found, be sure to use disinfection protocols outlined by the CDC.


To disinfect equipment to kill the virus that causes COVID-19, a disinfectant on the EPA's List N should be used. Before using a product, check to see if it has been registered with the EPA for use on dive equipment, respirators or the materials these are made of. Alternatively, the CDC recommends a 4:100 bleach solution (1/3 cup of bleach in 1 gallon of water) with a contact time of 1 minute.

After disinfecting equipment, one must take care not to re-infect the equipment, such as by handling it when storing. Dive shop employees should take care to maintain good hygiene by washing hands frequently and regularly disinfecting high-touch areas, including fill stations (as outlined in the “heat” section of this article).

When using any disinfectant, be sure to follow the manufacturer's instructions for use. Follow this with a thorough rinse in fresh water, and allow the equipment to dry completely before use.


Finally, consider updating your existing emergency action plan to include a potential COVID-19 infection by staff or customers. Be sure to outline all disinfection protocols and ensure that they are being diligently followed by all staff. The most important consideration is the health and safety of your staff and customers.


Divers Alert Network (DAN) has also issued some advice regarding protecting divers when they travel—and especially with respect to renting gear.


DAN states: “Equipment can be effectively sanitized by submerging it in a 10% bleach solution or using a cleaning product such as Steramine tablets or any other quaternary ammonium compound. Be sure to use these products according to the manufacturer’s directions and then rinse the gear with fresh water.


“Products that are commonly used to clean dive gear but are ineffective against coronavirus include antibacterial and chlorhexidine mouthwashes or sprays. Hot soapy water must be paired with mechanical action such as scrubbing with a soft toothbrush to be effective.”


If you’re traveling and using rental gear, DAN suggests using a “household disinfecting wipe” to clean your regulator mouthpiece, snorkel, BCD oral inflator and the inside of your mask, and then rinsing with fresh water before use. DAN advises you to ask your operator to sanitize the equipment you’re renting—if you don’t have access to wipes to do it yourself.

Dive Training


The main issue with training divers is how do we effectively teach them the important skill of air-sharing without potentially putting their health at risk. Training agencies require students to demonstrate in-water “air-sharing” exercises to meet general standards published by the various diving standards organizations. Widespread concerns surrounding the novel coronavirus and COVID-19 infection have demanded we allow changes to the way this skill is demonstrated and practiced during both confined skills training and open water certification dives.


Since RAID has a mandatory S-Drill and is a “primary” gas-sharing agency, cross-contamination is impossible to reduce. Therefore, RAID has designed a new proto