Dear MARNMP members,

 

We are entering a time of unprecedented difficulty. COVID-19 is an emerging infectious disease of global public health concern. It is a severe acute respiratory disease caused by SARS CoV-2 coronavirus which has infected over 100,000 people world wide. The first three cases in Malta where diagnosed at the end of this week. Our neighboring country Italy has 6387 confirmed cases with 366 mortalities as of 8 March 2020, most of them in the northern regions of Lombardy, Veneto, Emilia Romania and Piemonte. Italy went from 2 cases to over 6000 cases in a period of less than three weeks.

 

COVID-19 is the seventh known coronavirus to cause human infection. There are four known Coronaviridae that cause the common cold. In 2002-2003, SARS coronavirus infected 8422 people and caused 916 deaths, most in Guangdong province in China. SARS disease has since been successfully eradicated. Since 2012, MERS coronavirus infected 2492 people, the first In Saudi Arabia, killing 858 people so far.

 

How is COVID-19 different when compared to its predecessors? From medical literature published by the Chinese and from observation of its epidemiological behavior, it is evident that COVID-19 is much more contagious. Unlike SARS, COVID-19 patients seem to carry a high viral load during the pre-clinical, prodromal phase of the illness, making spread of virus in the community a lot easier. The spread index is estimated to be between 2 and 3, probably somewhere around 2.2. This means that on average, every infected person infects between 2 and 3 more people. The disease can only be controlled if this index falls below 1. The mortality of COVID-19 is significantly less than that of SARS and MERS. COVID-19 is believed to have a mortality of around 2%. Most of its victims are elderly people with pre-morbid conditions. There have not been any registered deaths among young children. The immune system of children can seemingly fight new viruses a lot more effectively than that of adults and more so, that of the elderly.

 

What else do we know? COVID-19 is an acute lung disease. The virus causes infection directly to the lungs, bypassing the upper respiratory tract. In 80% of cases, the infection is relatively mild and does not necessitate intensive measures. Most can stay at home. In up to 20% of cases, COVID-19 manifests as a more severe pneumonia, approaching a severe acute respiratory illness in 5 to 10%. In its most severe form, the disease is akin to the pathology known as diffuse alveolar damage, which manifests clinically as acute respiratory distress syndrome, ARDS. Chinese studies quote a 5% intensive care unit admission rate. In Italy, this figure presently stands at around 10%. It is notable to say that the average age of COVID-19 patients in Italy is higher than that seen in China. Italy has an older population.

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SARS CoV-2 is an RNA virus. Diagnosis can be confirmed using a polymerase chain reaction test on a sample obtained from patient’s throat. The initial sensitivity of the test may stand at around 60-70%, and repeat swabs may be necessary to increase sensitivity. PCR therefore has limited sensitivity but high specificity. Sensitivity may be increased by repeating the test.

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Chinese studies have shown that CT has high sensitivity in establishing the diagnosis. CT has high sensitivity. In the context of on going local spread of disease, which occurs during an epidemic, CT significantly adds to both sensitivity and specificity in establishing the diagnosis. The hallmark sign in early disease is unifocal or multifocal peripheral groundglass change. As the disease progresses, and in more severe cases, groundglass change is replaced by crazy paving pattern and consolidation, a picture similar to that of ARDS. Focal areas of nodular consolidation with groundglass halo and groundglass foci with a dense halo (reverse halo or atoll sign) have also been described in patients with COVID-19. These may indicate an organizing pneumonia reaction to the infection. CT, therefore may have a role in the early diagnosis of COVID-19 and may also be crucial in assessing the severity and in monitoring the progression of the illness. All radiologists should familiarize themselves with the CT manifestations of COVID-19.

 

What we don’t know. The World Health Organization has not yet declared COVID-19 as a pandemic. As of end of February and beginning of March, the disease seems to be spreading faster outside China, in several countries across the world. South Korea, Iran and Italy have become hot spots, but many other European countries have registered increasing cases. Are we still in a position to eradicate the disease? Will quarantine measures slow down the illness enough to allow health systems to cope with severely ill patients? Will the disease slow down during Summer months? And if it does, will we have a second wave in Autumn and Winter? Will COVID-19 become endemic to the human species? Are we going to be successful in developing a vaccine? Many questions remain un-answered.

 

What should we do now? First and foremost we should avoid panic. We should educate ourselves by reading and becoming aware what is happening around us. At the time of writing this message, Italy has locked down Lombardy and surrounding provinces in quarantine. Will this be enough to avoid spreading the disease Southward? We can only hope for the best. Until The World Health Organization issues more definite advice, it seems sensible to avoid all unnecessary travel and to enforce quarantine measures to limit spread of disease. We should follow the advice and instruction of our colleagues who are expert in Public Health and in Infectious Diseases. Hand washing, frequent use of alcohol rub, avoiding crowded places and such measures should be common sense behavior adopted by all.

 

As radiologists, we should take all possible steps to stay in good health, for our own sake and for the sake of our patients. We should make sure that our departments are protected in terms of patient flow in order to avoid crowding as far as possible. We should take all possible measures to protect patients (especially the most vulnerable) and staff. Barrier precautions should be instituted depending on the level of exposure, especially if the disease spreads in the local community. Xiao and Torok wrote this in The Lancet on 5 March 2020:

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“in the use of personal protective equipment, we should try to distinguish different risk factors, adopt different epidemic prevention measures, and reduce the waste of personal protective equipment, as these resources are already in short supply. Although surgical masks are in widespread use by the general population, there is no evidence that these masks prevent the acquisition of COVID-19, although they might slightly reduce the spread from an infected patient. High-filtration masks such as N95 masks and protective clothing (goggles and gowns) should be used in hospitals where health-care workers are in direct contact with infected patients.”

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30152-3/fulltext

 

We should follow the advice of local experts where it comes to use of protective equipment. Finally, radiologists may play a very important role in the diagnostics of COVID-19. We should all be familiar with the CT manifestations of the disease in order to help make a swift diagnosis and to stage the severity of the disease.

 

The world is facing a time of unprecedented difficulty. COVID-19 is a new viral illness that has taken humanity by surprise. At present, the disease is still on the rise in Europe and we don’t know when it will reach its peak. There is no doubt that for the foreseeable future, COVID-19 will severely influence our daily lives. Travel and public events, including sporting events have already been severely disrupted. We may be in for a long haul. There is no doubt that we have to redimension our expectations at both personal and community levels. We may need to rethink the way we go about our daily lives, not only in the short term, but also in the long term. Stay alert and positive. Read about the disease, discuss, educate and take care.

 

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Adrian Mizzi
President of the Maltese Association of Radiologists and Nuclear Medicine Physicians.

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