“We are in a pandemic situation: this means we have to remain vigilant”

Interview: Dr Pierrot Chitson

‘We have a significant elderly population making our fellow citizens a very high-risk target for the virus with consequent high morbidity and mortality’

Dr Pierrot Chitson MBBS, FRCP (Lond) has had a long career in the public service as Consultant Physician and Head, NCD/Health Promotion Division Ministry of Health and Quality of Life 1998-2000, and Adviser, Health Sector Reform 1993-97. Currently he is in private practice and is Chairman, Clinical Research Regulatory Council. With several publications to his name on the Non-Communicable Diseases and given his wide experience in their screening and epidemiological surveillance, a methodology which will be required as the country moves towards lockdown, we sought his views on this and other aspects of Covid-19.

* 46 days of lockdown: that should be enough, isn’t it, especially in view of the relative success of bringing local outbreaks of infections from Covid-19 under control?

Well, it can’t go on forever! But we need a plan ready so as to prevent a second wave which could be worse than the first one, because we don’t know the prevalence (spread) of the disease in the community. ‘Test. Test’ on a larger scale is needed, and isolate positive cases. It will be a long “guerrilla warfare” because a) asymptomatic people carry and spread the virus silently, b) we are still learning about the disease. Asian countries are using artificial intelligence to track and warn people of the danger but a balance will have to be struck between individual privacy and personal/state security. The aim is to ‘flatten the curve’ i.e. bringing the infection to insignificant levels which some countries managed to do followed by precise surveillance and quick isolation/treatment. It’s not too late for us to be relatively virus free if we act resolutely. A second wave might overwhelm the health services.

* Given the population size of Mauritius and the resources available locally, would you say that we have indeed managed the Covid-19 situation here rather well?

We are all always wiser after the event, but we had some unfortunate deaths! I think Government took the right decision in the nick of time. But no man is an island: as we re-open up, the same scenario may haunt us again unless there is widespread community mobilisation and strong community leadership led by medical professionals. The world is still on a learning curve for Covid-19 – intensive care of critical patients on invasive respiratory support does not appear to be the right solution. This disease is quite complex and hopefully medical science will have new methods of treating the disease soon in a more rational and humane way.

* In what way is this pandemic different from the AH1N1 pandemic?

The H1NI virus has been with us since the beginning of at least the 1918 Spanish flu which killed millions of people. It disappeared and came back many times; in 2009 re-combined with the porcine species killing thousands of people, especially the younger ones as the elderly people had some past immunity from previous H1N1 epidemics (1950s). However Covid-19 is around 10 times nastier (according to WHO) being a new virus and it is currently creating havoc in old people’s homes in ‘advanced’ countries. Children and youth are relatively spared but young obese adults and those with chronic illness are also at risk. We don’t know how the virus will mutate and whether we will have immunity after infection; this makes vaccine development uncertain.

* The lockdown is due to end on May 3, and government has announced that tests are going to be carried out on 35000 ‘frontliners’ in the health services, supermarkets etc. What else needs to be done so as to end the lockdown safely and effectively?

It is the right direction and these tests will give us an idea of the situation in Mauritius – probably the prevalence will be on the low side (<1% ) but one single case like elsewhere if not isolated, will silently spread in the community. That’s why we have to keep ‘Testing, testing’ the community especially later when we open up our ports.

We are in a pandemic situation: this means we have to be vigilant until the world sorts out this disease. This might take some time, hopefully before the end of the year. We also have to hope that a vaccine will work or that the virus will gradually become less virulent. In the meantime Mauritians will have to be more disciplined in social distancing and hygiene, and we will need to change our working habits by working more at home using digital technology.

However we know as doctors how difficult it is to avoid contamination even in a medical set up! And the elderly will need to be protected, especially those in homes, and elderly doctors will have to make more use of telemedicine eventually as they are needed to guide the younger generation.

* Can you throw some light on the types of tests, their importance in the control of the pandemic, and their relative merits?

No laboratory tests are 100% reliable; that is why all doctors have been trained in the art of using clinical and epidemiological data to make diagnostic decisions together with the help of laboratory or other technology. Currently the polymerase chain reaction (PCR) is a method used widely in molecular biology to identify actual virus infecting the person but the test is quite expensive, complicated and slow. There may be false negatives (patient having the disease but the test is negative) due to a host of factors and doctors have to take this in consideration in the management of any patient.

Rapid diagnostic tests are being developed. One type of RDT detects the presence of viral proteins (antigens) of Covid-19 virus in a swab from the respiratory tract of a patient. The antigen(s) detected are found only when the virus is actively multiplying and indicate acute or early infection. The test takes around half an hour, is easier and less costly. This antigen will probably be used as a screening test backed up by PCR for confirmation.

Rapid antibody tests (antibodies are proteins produced to fight against the virus) can be detected in the blood of most patients around a week after first symptoms of infection, and the IgG component stays many months in the patient. Thus the antibody test can be a useful tool in epidemiological studies but not good enough for actual diagnosis. However, it may help in patients who are antigen/PCR negative but still suspicious of Covid-19. Previously a case in Singapore was diagnosed from the antibody test. We still don’t know if a positive antibody test indicates immunity and for how long.

* What next after the tests in terms of accompanying measures based on the results they yield?

Soon these rapid tests when well validated will become important tools for surveillance of the disease – present and past. The antibody test will be able to help the decision makers as it will give timely information on the progress of disease in a given population as many patients don’t know if they had the disease (asymptomatic). The antigen test will help the health authorities to detect, isolate and treat patients rapidly, and the antibody test will indicate the spread of the disease in the community. Both will be important. Eventually if around 60-80% of the population are antibody positive, then ‘herd immunity’ is achieved meaning that the virus will be contained and might disappear from the community for some time.

* If there are good reasons for easing the lockdown with a view to reviving the economy as well as to mitigating its psychological effects on the population, what happens if a vaccine takes a long time coming?

I think the lockdown was a necessary shock therapy for our population who I hope will realise that things won’t be the same again in the near future and that we will have to adapt to the new habits of social distancing. The vaccine is in the distant future and hopefully it will be effective especially in the elderly population who are already at very high risk. Just like AIDS, I hope we can have an effective drug treatment soon, and affordable. Best is to hope for the virus to weaken with time.

Can we let the young out and keep the elderly confined for so long? And can we afford to close the island for a long time with no movements of students, tourists, or foreign workers? We will need to learn from other countries which are at ‘war’ with this dangerous virus at different stages using different strategies.

* China, South Korea and Singapore are already going through it and some other Asian countries face a possible second wave of coronavirus infections. Is it likely to happen here, and can it get worse in terms of its spread and death toll?

We shall be lucky if we can avoid a second wave when we open up the economy and the country provided Mauritians decide to behave like the East Asians with discipline and comply with the health authorities. I think the population seems to be well aware of the situation and if Government/private sector/religious bodies and the community/‘forces vives’ work in tandem, then we may avoid the coming health catastrophe.

We must note that most adult Mauritians already have at least one underlying health problem like diabetes, obesity, hypertension, heart disease, auto immune disorders, cancer in remission, chronic lung disorders, alcoholism, etc. We also have a significant elderly population making our fellow citizens a very high-risk target for the virus with consequent high morbidity and mortality. Our health system might become under huge siege as in Europe and America at the moment.

* What lessons do you think should we draw from the coronavirus pandemic which may allow us to strengthen our preparedness for any future virus outbreak?

I think that international collaboration is crucial and the epidemic preparedness mechanisms must be reinforced through the WHO. Unfortunately there was no political will from the richer powers in funding for epidemiological preparedness, research in pathogenic micro-organisms, and future vaccines. I well remember in the 1990s when I was attending WHO meetings, the control of re-emerging infectious disease was on top of the agenda but not much seems to have been done considering the unpreparedness of most countries. We must also learn to respect nature especially the animal kingdom and be less greedy in our food choices!

* Published in print edition on 28 April 2020

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