After Covid, when is it safe to go back in the water?

Had Covid? Can you still dive ok? When is it safe to go back in the water?

In response to member inquiries, our evolving understanding of the impacts of Covid-19 on divers, and considering the evolution of variants on vaccinated people, the DAN Euro Medical Team issued new guidelines to determine Fitness to Dive after Covid-19.
Below this is Worksafe New Zealand's latest advisory, especially relevant to occupational divers.

In May 2020, DAN Europe had published consensus recommendations for divers returning to diving after they had been infected with the virus. The recommendations are based on medical advice compiled by the Undersea and Hyperbaric Medical Society (UHMS) in the USA, the Belgian Society for Diving and Hyperbaric Medicine (SBMHS-BVOOG), and the European Committee for Hyperbaric Medicine and Underwater and Baromedical Society (ECHM & EUBS). The University of California at San Diego (UCSD) also issued medical guidelines for recreational, scientific and commercial divers.

Since 2020, with diving resuming in many locations, especially local diving, DAN has fielded inquiries from divers who had suffered from Covid-19 about when they can safely return to diving and what, if any precautions they should take. So we are republishing the medical recommendations shown below as well as adding the recent field experience of some DAN Europe physicians who have treated and/or advised divers who have had the virus.

Medical recommendations for returning to diving
For the most part, the medical advisories cited above discuss the various manifestations of the virus and the risk of its spreading, along with some of the known risk factors that likely determine the severity of the illness. The authors were careful to point out that at the time that advisories were being prepared, scientific data was scarce, but clinical publications have shown cases with severe deterioration of the lungs, heart, central nervous system and kidneys after Covid-19 infection.
Specific concerns were raised for divers. Similar to other serious virus pneumonias, divers who have been infected with Covid-19, require a period to convalesce before returning to full activities, a process that can take weeks or months depending on symptom severity.

The consensus recommendations for returning to diving after Covid-19
Note that the guidance for divers who tested positive for COVID-19 but remained completely asymptomatic, and the guidance for those who were symptomatic but not hospitalised, have been updated since the original recommendations were made in early spring 2020. These are shown below. Also be aware that guidance and recommendations may vary slightly among countries. National recommendations were created to cope with what was hitherto a largely unknown form of cardiopulmonary disease and cannot be expected to be entirely uniform across counties and cultures. However, all guidance urges divers to exercise caution.

UPDATE - February 2022
Recommendations:
·       Divers who have tested positive for COVID-19 but remained completely asymptomatic should wait at least 30 days from the first negative test before applying for fit-to-dive clearance and eventually going back to diving.

·       Divers who have had symptomatic COVID-19 should wait at least 30 days from the first negative test, plus an additional 30 days without symptoms (a total of two months) before applying for fit-to-dive clearance conducted by a diving medicine specialist.

·       Divers who have been hospitalised with, or because of pulmonary symptoms in relation to COVID-19, should wait at least THREE months before applying for fit-to-dive clearance conducted or coordinated by a diving medicine specialist. The clearance should include complete pulmonary function testing (at least FVC, FEV1, PEF25-50-75, RV and FEV1/FVC), an exercise test with peripheral oxygen saturation measurement, as well as a high resolution CT scanning of the lungs to verify a return to normal.

·       Divers who have been hospitalised with, or because of cardiac problems in relation to COVID-19, should wait at least THREE months before applying for fit-to-dive clearance conducted or coordinated by a diving medicine specialist. The clearance should include cardiac evaluation, including echocardiography and an exercise test (exercise electrocardiography) to ascertain normal cardiac function. It is important these pulmonary and cardiac tests are interpreted and validated by a medical officer with specific knowledge of diving medicine.

Other risk factors

There may be further potential risks for divers who have had Covid-19. The best way to determine if you might be subject to a higher risk for pulmonary barotrauma, lung bubble shunting, cardiac or other problems is through a recommended diving medical exam. Divers who may be at higher risk should consider the following in resuming their diving activities in consultation with their diving doctor.

Pulmonary overpressure syndrome (lung barotrauma): Divers who experienced severe pulmonary symptoms may suffer from prolonged or even permanent pulmonary damage, even if the lung function seems to have returned to (near) normal. This damage may give a higher risk for lung barotrauma, even after dives without a rapid or uncontrolled ascent. (Reference: Belgian Society for Diving and Hyperbaric Medicine)

Pulmonary oxygen toxicity: At this time, there is very little known as to a possible increased sensitivity of the pulmonary tissue to the toxic effects of oxygen; therefore, a prudent attitude would be that technical diving with prolonged breathing of hyperoxic gas, with a PO2 of 1.3 ATA or higher, for example rebreather diving, should be avoided. Simple “nitrox diving,” whereby a maximum PO2 of 1.4 ATA is only breathed for short periods, at the deepest part of the dive, should not present any problem. (Reference: Belgian Society for Diving and Hyperbaric Medicine)

Decompression illness: Even less is known about the possible alteration of the “bubble filter” function of the lung after COVID-19 pulmonary infection. This may imply that the risk for decompression sickness could increase significantly. Therefore, a prudent attitude would be that divers who have suffered from pulmonary symptoms of COVID-19, limit their dives temporarily (or definitively) to well within the no decompression limits (NDL) of their computer (so that at no moment during the dive, the computer indicates mandatory decompression stops). (Reference: Belgian Society for Diving and Hyperbaric Medicine)

Prevent the spread: Covid-19 and diving operations
It is expected that the Covid-19 will persist in the community leading to a continued risk of transmission between persons if in direct proximity or sharing common personal equipment. Every dive centre or diving team should conduct an analysis of risk prevention and mitigation using published recommendations. Divers and dive centres should observe strictly the guidelines for disinfection of diving gear as issued by the diving federations and DAN.

In general DAN recommends:

• To continue social distancing measures as required by the local authorities also during diving operations (mostly during the surface phase of diving operations) including wearing masks and maintaining a safe social distance.
  
• To disinfect private and rental equipment, including emergency oxygen units, with appropriate disinfectants covering broad spectrum of germs, including fungi, bacteria, spores and viruses.
  
• To avoid exchange of personal breathing systems except in real emergency situations.
  
• To plan any “breathing systems sharing” exercises in such a way that personal protection is ensured.
  

By following these recommendations divers can mitigate the risks of spreading the virus and divers who have had Covid-19 can resume diving activities in the safest manner possible.

So when is it safe to get back in the water?

An article by Dr Frank Hartig in Wetnotes, a German magazine, over two years ago indicated the type of medical problems that scuba divers who have had Covid might face. Dr Hartig is a senior consultant for SARS-CoV-2 at Innsbruck University Hospital in Austria, and a scuba diver.
He described six active scuba divers hospitalised with conditions brought on by Covid-19 who subsequently recovered and were discharged. But when they returned for a check-up 5 to 6 weeks later, although they all outwardly appeared healthy, a closer examination proved otherwise.
“In two of them,” writes Dr Hartvig, “we saw significant oxygen deficiency when under stress as a typical sign of a persistent pulmonary shunt. In two others, bronchial tubes were still very irritable during exercise, as in asthmatics. Four of the six divers in the check-up CT [scan] still had significant lung changes. None of the six divers can be released for diving for the time being, despite their wellbeing.’

A pulmonary shunt is when blood fails to pick up more oxygen as it passes through the lungs, which leads to the body being starved of oxygen and is often caused by fluid in the lungs which is also the result of pneumonia and pulmonary oedema, a condition becoming widely recognised as a leading cause of diver fatalities.

From Dr Hartig’s assessment, divers who are affected by the coronavirus should not dive until they have had a thorough medical examination – even if they otherwise appear healthy.

In the short-term the advice is clear. Covid-19 can damage the lungs and the heart. Scuba diving with damage to any part of the cardiovascular system can lead to serious injury and death.

COVID-19 and diver safety

WORKPLACE SAFETY NEW ZEALAND SAFETY ALERT [Especially relevant to Occupational Divers issued in February 2022]

This safety alert updates the previous advice issued in May 2020 and highlights the serious health and safety risks posed for occupational divers if they have been exposed to coronavirus COVID-19.

What happened?
In the last few months we have seen the global spread of the Omicron variant of COVID-19 and its entry into the New Zealand community.
The New Zealand Government has moved to a Protection Framework (traffic light system) whereby the spread of COVID-19 will become more commonplace within the workforce.

Though many people may not be affected, those that are, can range from being asymptomatic (showing no symptoms) to suffering from severe respiratory responses. Incidents of respiratory distress have resulted in some people showing possible longer-term damage to their lungs.
This increases the potential for serious harm to divers and highlights the importance of establishing safe medical standards for those who may have been infected with COVID-19. International experience and medical studies have allowed hyperbaric specialists to establish updated advice on what to do if exposed to COVID-19 and how to best protect divers.

What we know

A respiratory injury can cause serious harm to a diver. Occupational divers have to pass annual medical assessments to be deemed to be medically fit. Though there has been no formal study into the effects of COVID-19 on occupational divers, general clinical observations indicate that COVID-19:
·                   transmits easily from person to person
·                   a person may be asymptomatic but still test positive
·                   may not present symptoms for 10–14 days
·                   often shows symptoms similar to influenza
·                   can include serious respiratory disease such as chronic lung disease or moderate to severe asthma.

The best way to protect yourself and others around you from the effects of COVID-19 is to be double vaccinated and boosted.

WorkSafe advice

Anyone with respiratory symptoms should not dive and should arrange for COVID-19 testing. If testing is negative, they should see their GP for further advice and appropriate treatment for their symptoms.

Anyone being vaccinated should monitor for any side-effects (generally these are nil or mild) and do not dive if feeling unwell. A return to diving can occur when any symptoms have passed.

If someone is a ‘Close Contact’ (as per the Ministry of Health classification) they should not dive until cleared by the Public Health Service (PHS) to return to work. See the Ministry of Health’s website for the definition of Close Contact.

If someone has tested positive for COVID-19 they must not dive even if they are asymptomatic. Anyone testing positive for COVID-19 should advise the Diving Hyperbaric Medicine Service (DHMS) at divemeds@gmail.com and follow any Health advice.

If tested positive for COVID-19 refer to the following table before returning to diving:


Remember – you must advise the DHMS if you have received a positive COVID-19 Test result and also once cleared by the PHS.

COVID-19 can have serious medical effects for divers. All workers and Persons Conducting a Business or Undertaking (PCBUs) have an obligation under the Health and Safety at Work Act 2015 to ensure their own health and safety and the health and safety of those around them. Monitoring for signs and symptoms of COVID-19 and following this medical advice will help manage the risks for occupational divers.

Further information

Occupational diving guidance
List of designated diving doctors
Diving Hyperbaric Medicine Service

Acknowledgement
This safety alert has been developed in consultation with Diving Industry Advisory Group hyperbaric medical specialists.