What is the difference between an epidemic and pandemic?
Epidemic means “a temporary prevalence of a disease.” The World Health Organization (WHO) further specifies it occurs at the level of a region or community. A Pandemic on the other hand, means an epidemic which has spread over a large area, ie: it is “prevalent throughout an entire country, continent or the whole world.”
We have all either heard about or lived through several disease ‘epidemics’ in modern history. These have included the ‘Spanish ‘Flu’ – also known as the ‘1918 ‘flu pandemic’ lasting from January 1918 to December 1920. Staggeringly, it infected 500 million people, about a quarter of the world’s population at the time! The death toll is estimated to have been anywhere from 17 million to 100 million, making it one of the deadliest epidemics in human history.
The Spanish ‘flu was the first of two pandemics caused by the H1N1 influenza virus; the second was the ‘Swine ‘flu’ which lasted from January 2009 to August 2010. The virus appeared to be a new strain of H1N1, which resulted from a previous triple combination of bird, swine and human ‘flu viruses further combined with a Eurasian pig ‘flu virus.
What is difference between the SARS and COVID-19?
Before swine ‘flu, there was the ‘Severe Acute Respiratory Syndrome Coronavirus’ or SARS epidemic in 2003 (official name SARS-CoV but which was more often referred to as ‘Bird ‘flu’) which resulted in more than 8000 cases and 800 deaths. It caused panic in scientists because viruses had not previously jumped between species creating panic that the human race was more vulnerable than ever before.
Now there is a mutated SARS virus on the loose which began in December 2019, a novel coronavirus (SARS-CoV-2), from Wuhan, China led to a rapidly spreading outbreak of coronavirus disease (COVID-19). So SARS and COVID-19 are very closely linked (86 per cent the same) – they both attack the respiratory system like a severe pneumonia.
Symptoms are a high fever, shortness of breath, a dry cough and aching muscles. It is not like the common cold or the ‘flu. Sadly, like pneumonia it can be deadly in high loading doses and even in milder doses to the vulnerable. The really worrying difference for epidemiologists analysing this virus is that although the progression for patients follows a similar pattern in both diseases, with progression to acute respiratory distress syndrome approximately eight–20 days after onset of first symptoms.
By contrast, by the end of February 2020, within a matter of two months since the beginning of the outbreak of coronavirus disease 2019 (COVID-19), more than 82,000 confirmed cases of COVID-19 have been reported with more than 2,800 deaths. SARS caused in total from 2002-2004, 774 deaths from 8,098 cases. This shows that COVID-19 is much more virulent and so drastic measures may not even be enough to curb its rampage. We may all have to succumb to it whether we want to or not.
The potential advantage could be it may then avoid us being vulnerable to a mutated more deadly strain next Winter but this is second guessing its characteristics and we so not know whether this is how it operates in these early days of studying it.
How to avoid transmission?
The virus is typically spread from one person to another via respiratory droplets produced during coughing. It primarily spreads when people are in close contact but may also spread when one touches a contaminated surface and then one’s face. It is most contagious when people are symptomatic but this may be possible before symptoms appear which makes it almost impossible to stop the spread if a person is unaware they are a carrier without enforcement of a curfew.
Efforts to prevent the virus spreading include travel restrictions, quarantines and now curfews of entire populations as event cancellations and facility closures have not proved to be successful. Without education as to why seemingly healthy people cannot leave their homes, to effectively prevent movement of a population for weeks is nigh on impossible outside of a police state like China.
By interrupting all human-to-human transmission, SARS was effectively eradicated a few years ago. Although there are striking similarities between SARS and COVID-19, the differences in the virus characteristics will ultimately determine whether the same measures for SARS will also be successful for COVID-19. We are all living in hope that we do not lose a quarter of the world’s population or even more in this pandemic like we did in 1918, by enforcing curfews worldwide.