Sun | Dec 5, 2021

Garth Rattray | Silent but deadly COVID-19 spreaders

Published:Monday | October 11, 2021 | 12:07 AM

The forerunners of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), are Severe Acute Respiratory Syndrome Coronavirus 1 (SARS-CoV-1) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) – they are both also zoonotic viruses (that made the leap from animals to humans) and occurred in 2003 and 2012, respectively. They were capable of being more lethal than SARS-CoV-2, the virus that causes COVID-19.

The SARS-CoV-1 outbreak ended by 2004; it lasted about 18 months. It was spread by close contact. During the outbreak, 8,098 people became sick worldwide and 774 died from the virus. The overall case fatality rate (CFR) was about 10 per cent. However, it was estimated that the CFR for people older than 64 years was greater than 50 per cent.

The SARS-CoV-1 epidemic did not merely burn itself out; it was stopped by simple public health (non-pharmaceutical) measures – distancing, sanitising, and the effective wearing of masks. Widespread testing, isolating those with symptoms, quarantining contacts and suspected infected individuals, along with travel restriction, also played major roles in ridding the planet of that virus.

MERS-CoV is still active and, up to March 2021, a total of 2,574 confirmed cases and 886 associated deaths were reported globally, but mostly found only in about seven countries. The CFR is approximately 34.4 per cent.

SARS-CoV-2 (the virus that causes COVID-19) has a CFR of (only) about three per cent, yet it is proving far more lethal than its predecessors. Despite its relatively low CFR, it has made 219 million people sick and caused 4.55 million deaths…so far. SARS-CoV-2 is persisting and comes in very deadly waves.


The reason that SARS-COV-1 disappeared and MERS-CoV remains somewhat obscure is that both require close contact for transmission and infected individuals manifest signs of viral infection readily and early in the disease process. In other words, if anyone were suspected of possible exposure, they were quickly quarantined. And those who contracted either virus were quickly isolated.

On the other hand, COVID-19, caused by the SARS-CoV-2 virus, is extremely transmissible, unpredictable, and remarkably sneaky. Most infected individuals experience and exhibit absolutely no symptoms or signs of infection. Some experience minor symptoms that are often erroneously attributed to tiredness, allergies, a recurrent sinus problem, a regular cold, fleeting aches and pains, or feeling a little ‘off’ for a short while. A minority become sick enough to seek medical intervention (testing and/or treatment), and a percentage of that minority become seriously ill, or critically ill, or die.

The fact that most infected persons do not become sick bodes well for them, but belies that grim reality that the absence of symptoms and signs of disease is the reason why those individuals become silent but deadly COVID-19 spreaders. There is therefore a paradox wherein this less deadly virus causes far more fatalities than some more deadly viruses. In other words, stealth is this virus’ superpower. Herein lies the reason why COVID-19 spreads so rapidly across the globe, persists today, and has been around long enough to mutate into several variants.

The COVID-19 monster has found allies in people who assume that they will either not become infected and that, if infected, they will experience little or no symptoms. Sadly, they never stop to consider that their luck might run out or to wonder how much suffering, death, socio-economic disruption and health system malfunction they might be causing by spreading the virus unknowingly. They find it uncomfortable or inconvenient to protect themselves and others for the good of our entire country.

COVID-19 will never go away until people practise social distancing, sanitising, and wearing masks properly. Most feel invulnerable among friends and within their work and social groups.

We need vaccines to end this unnecessary cycle of suffering, death and significant disruption of our healthcare system.

Garth A. Rattray is a medical doctor with a family practice. Email feedback to and