In December 1518, a smallpox epidemic broke out on the island of Hispaniola, decimating the enslaved African miners, which rapidly spread to the indigenous Taínos, who had no immunity to the disease.
By May 1519, as many as one-third of the remaining Taínos had succumbed to the virus. From Hispaniola, smallpox spread by ship to Mexico, and thence, courtesy of Herná* Cortés, to the Aztec empire. Like the Taínos, the Aztec people had no immunity to the disease, and over the next 200 years, smallpox spread throughout the two Americas, and systematically wiped out 90% to 95% of the native American populations.
Smallpox was a novel virus when it was introduced into the Americas, which means that no single native of the New World had been exposed to the virus before. It also meant that nobody had immunity to the disease.
SARS-CoV-2, the virus that causes Covid-19, is also a novel virus. Until it crossed the animal-human barrier (hence its classification as a zoonotic virus) and infected somebody at a bushmeat market in Wuhan, China, no human being on the planet had been exposed to it. This is why, despite its fatality rate being a fraction of that of smallpox, it poses a major threat to the global human population, because at the time of transmission to the human population, nobody had any immunity.
At the time of writing, South Africa had 61 confirmed cases of Covid-19, and reactions seem to be divided between “We are all going to die” to “What’s all the fuss about? This is no worse than the seasonal”. Neither perspective is accurate.
The news cycle is completely dominated by Covid-19 and its gradual spread around the globe, and as the numbers tick upwards, society reacts in typical flight or fight fashion.
Panic buying is now the order of the day in many locations where the infection rate is climbing, in anticipation perhaps of the order of lockdown imposed in Hubei Province in China (the epicentre of the pandemic), and Italy thus far.
Because it is a novel virus like the Spanish Flu pandemic of 1918, COVID-19 will work its way around the world infecting most of the world’s population. The overwhelming majority of people who contract the disease, will recover with no residual effect, except possibly a measure of immunity. As time passes, and the disease infects more people who recover, herd immunity will slowly develop.
Herd immunity is resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals (between 83% and 94%) are immune to the disease, especially through vaccination, but also through the human immune system developing anti-bodies as the result of successfully fighting off the infection – in this case, Covid-19.
The development of a vaccine is already under way, but because of the stringent mandatory testing protocols to ensure safety and efficacy, it is unlikely that there will be one commercially available inside of six months.
A great many people around the world (the numbers are unclear at this time) will inevitably contract Covid-19, despite the best efforts of international and national public health agencies like the WHO, the American Centres for Disease Control and Prevention (CDC), and national public health departments, but it is the speed with which the pandemic spreads that will determine the ultimate public health consequences.
The slower the spread of the disease, the greater the likelihood that the public health infrastructure will be able to cope with the number of new infections, at any given time, requiring medical attention, be that out-patient treatment or hospitalisation.
It is for this reason that measures to slow the spread of the disease – in simple terms, reduce the number of new infections per day – are so critical, be that exclusion (keeping the disease out, which thus far has been singularly unsuccessful), containment (keeping the disease in, which has also been singularly unsuccessful), maintaining strict personal hygiene standards, or social distancing.
In America, for example, between March 1 and March 13, 2 103 new infections were reported, making the growth curve exponential in nature. Were the number of new cases to continue to double every three days, by May there could be as many as one hundred million cases in America.
Slowing the spread of the disease will flatten the curve, so to speak, and according to Somerset West epidemiologist, Dr Jo Barnes, it is up to every individual to take the already widely publicised actions of maintaining personal hygiene (regular and thorough hand washing, coughing into a tissue or one’s elbow, not touching one’s face), maintaining immune system robustness, and most importantly, social distancing (working from home where possible, reducing travel to an absolute minimum, self-excluding from public places as much as possible, maintaining one to one-and-a-half metre distance from others, no hugging, handshaking, or touching).
The economic and political consequences of the pandemic, over which we as individuals have virtually no influence, have already begun to play out across the globe, and are likely to be signficantly greater and longer-lasting than the public health consequences.
The least we can do, is play our part in slowing the spread.