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The human race has faced epidemics of known and unknown diseases in the past and has survived. Let's then first get one basic fact clarified—Severe Acute Respiratory Syndrome (SARS) isn't likely to eliminate the human race. Stories of masked SARS victims make for good visuals and sound bites. What the media doesn't realise is the magnitude of unnecessary panic it creates among the public. Pneumonia or lower respiratory tract infection is the most common infectious disease in adults with a potential to kill. On an average, 10 to 30 per cent of people hospitalised with pneumonia succumb to it, with a higher risk of death with increasing age. SARS is just another type of pneumonia, the only difference being that it's caused by a coronavirus, a strain that hasn't been studied and characterised so far.
The main reason for the panic is that apart from the coronavirus being unknown to us, it has also spread very rapidly. People who have travelled to China, Singapore, Vietnam or other SARS-affected countries have been infected. And they, in turn, have infected others back home. A close monitoring of the who website suggests that the SARS curve is now on the decline, slowly, after reaching its peak some time back. Vietnam hasn't reported any new case in the last 20 days (twice the time of the virus' incubation period). I believe the graph will follow a similar pattern in India too—it's on the rise right now and within weeks or a month will show a decline. It's a conclusion based on the fact that every new infection affects a large population initially—there is no resistance to the virus from the human body, and thus the casualties. However, there will be many who will not develop the disease. Slowly, immunity develops in people from sub-clinical/minor infection and the epidemic gets limited. Even then, the mortality rate is dependent on the magnitude of exposure. Certain very virulent viruses, like the Ebola in Africa, can cause death even with a low level of exposure. But fortunately, the SARS virus is different—you have to be infected with a certain quantum to develop the disease. Therefore, not everyone who has been exposed or is infected by the coronavirus will develop SARS. Neither will everyone who gets infected die. The case fatality rate from SARS is only 3 per cent as per reports from the Center for Disease Control, US.
A substantial number of people may be infected in India too. But their level of exposure isn't as much to be manifested in the disease. They are bound to spread the infection further. However, with time, immunity against the virus will rise. As with all contagious diseases, its virulence will decline in subsequent cases and the fatalities will reduce. So, unless you have been frequently travelling in an affected area and have been infected very badly, there is no need to panic. But how do we deal with badly-infected cases? There are diagnostic problems with SARS. That is nothing new—whenever a pneumonia patient is brought to a hospital, doctors don't have enough time to determine which organism has caused it. It may take weeks to isolate and identify the infection. This is particularly true in the case of SARS too where the diagnostic tests aren't yet foolproof.
Let's not forget that except for the culture test, all other diagnostic tests—whether it's ELISA or RT-PCR—are ridden by inherent limitations. False positivity or false negativity cannot be ruled out. This is a problem that clinicians face everyday and they still make a rational decision and treat pneumonia with a combination of antibiotics that cover common infections. It's also important to remember that a suspected case of SARS may have some other infection and there is no clinical test yet which can diagnose SARS. Infected patients carry the risk of developing acute respiratory distress syndrome (ARDS) which is the actual cause of death.But then, any severe pneumonia can get complicated with ARDS and this complication has a very high fatality rate. Every pneumonia patient has to be monitored, should he/she develop ARDS. It really does not matter which virus has caused it. Whether it's coronavirus or pneumococcus, the idea is to detect ARDS as early as possible.
Worries about the virus not having been identified and analysed are unfounded. This is primarily because the identification of the virus, besides academic understanding, has little bearing on its treatment as anti-viral drugs are rarely used in pneumonia. This is where I must stop short of dismissing the need to be alert about SARS, just like we need to be alert about TB or influenza. The fact is that 10 to 30 per cent of pneumonia cases die in hospitals. This is true not just of India but for all developed countries as well. So, pneumonia in itself is a serious disease and we need to be cautious.
But being cautious doesn't mean we go around wearing masks. The commonly used surgical mask is unlikely to provide 100 per cent protection. Quarantine or isolation of patients with obvious symptoms like fever, cough and shortness of breath helps. It will also help if you avoid travelling to SARS-affected countries in the near future.
We don't need to be greatly troubled or let images of patients in isolation surrounded by masked doctors scare us. It's true that SARS has arrived in India. It's also true that a very small percentage of the infected persons will develop the disease and still, a smaller percentage may succumb to it. We need to tackle SARS with the same seriousness with which we handle all pneumonia cases.
(The writer is a senior faculty member at the All India Institute of Medical Sciences, New Delhi. He has written several research papers on pneumonia.)