Covid-19 jargon buster: from apex to zoonotic disease

The National's guide to all the terms you'll read in coverage of the pandemic

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The Covid-19 pandemic comes with its own lexicon of terms, from herd immunity to contact tracing.

Here’s a glossary spelling out the phrases that have defined the first four months of 2020:


Commonly used by authorities to describe the peak of the disease when the caseload is at its highest in different countries and cities.


Someone is asymptomatic when they show no signs of having the disease but may still be infected. On average, it takes five to six days from being infected with the virus for symptoms to show, however it may take as long as 14 days, according to the World Health Organisation.


This medication, along with its derivative hydroxychloroquine,

is primarily used to treat malaria but have been suggested as a possible treatment for Covid-19. Various trials currently underway have had mixed results, with growing concerns about their impact on the heart. President Trump sparked controversy when he touted chloroquine as a "miracle" cure, prompting a backlash from health experts warning it had yet to undergo testing to treat Covid-19.

Community spread

The spread of a contagious disease in a certain area to individuals who have had no known contact with others infected, meaning the source is unknown. This, according to the US leading coronavirus expert, Dr Anthony Fauci, makes it impossible to predict the number of cases of Covid-19.



Diseases that are infections, ie easily transmitted, are communicable. This includes Covid-19, which has alarmed health experts with the speed of its spread, reaching one million infections over several months and accelerating past two million in less than a fortnight.

Contact tracing

A monitoring process that follows people who have been in contact with those who are infected as a means of reducing transmission. This means individuals can get treatment or self-isolate before infecting others and is one of the primary methods being explored to slow the spread of Covid-19.


This is a family of single-stranded RNA viruses that cause a range of illnesses in humans and animals, including the new coronavirus known as Covid-19. They also cause MERS (Middle East Respiratory Syndrome) and SARS (Severe Acute Respiratory Syndrome).


A highly infections respiratory disease caused by the new coronavirus that was first reported in Wuhan, China in December 2019 before spreading rapidly around the world. As of April 21, the coronavirus had caused almost 2.5 million infections and 171,338 deaths worldwide, prompting many countries to impose lockdowns and quarantine some communities. The disease appears to have a more severe effect on older adults and people with underlying health conditions with symptoms ranging from mild to severe.

Flattening the curve

The curve refers to the number of cases over a period of time and flattening it means preventing a surge of new cases in quick succession. Put together, the idea behind flattening the curve is to slow the spread of the disease so that healthcare systems don't become overwhelmed and can cope with the number of patients requiring medical care each day.

Epidemic and pandemic

A disease can be declared an epidemic when it is actively spreading across a wide area and is used to describe a problem that has grown out of control. The term pandemic is used in relation to geographic spread, when a disease affects a whole country or the entire world. A pandemic is a type of epidemic, but with greater range and coverage and affects an exceptionally high proportion of the population.

Herd immunity 

If a sufficiently high percentage of a population become immune to a disease, it stops the infection from spreading. This can either happen if many people contract the disease and built up natural immunity over time, or if enough people are vaccinated to prevent it from spreading. Once enough people are immune, they provide buffers to those who aren't and the disease can eventually be eliminated, which is what happened with smallpox.

However, the more infectious the disease, the higher population immunity needs to be. According to vaccination alliance Gavi, herd immunity for the new coronavirus could be achieved when around 60 per cent of the population becomes immune to Covid-19. However, there is no guarantee that this will work or would prove an effective method in battling the virus as there are still many unknowns about Covid-19.


Misinformation and disinformation

Along with fake news, these terms have been the subject of much debate during the coronavirus outbreak with warnings over the various types of false information circulating on social media and some mainstream media platforms. However, the main distinction is over the intention to mislead – misinformation is something shared by someone who may or may not know it is false whereas disinformation intends to mislead or present biased information to create a narrative or dispute facts.


Middle East Respiratory Syndrome is a viral respiratory illness from the coronavirus family that causes a fever, cough and shortness of breath. The first cases were reported in Saudi Arabia in September 2012 and subsequently spread to several other countries, although it was later found to have originated in Jordan in April 2012. Symptoms can often progress to pneumonia or kidney failure and about three or four out of every 10 people to have contracted MERS have died, according to the US Centres for Disease Control and Prevention.


Another coronavirus, Severe Acute Respiratory Syndrome is a viral respiratory illness that initially emerged in Guangdong, China in 2002 before spreading across more than two dozen countries in Asia, North America, South America and Europe. No known cases have been reported since 2004. The epidemic resulted in 8,000 known cases, 15 per cent of whom died, giving it a higher mortality rate than Covid-19.

Seasonal Flu 

This strikes annually and affects nine per cent of the population, resulting in around one billion cases a year. About five million of these are severe and about 0.1 per cent, or between 291,000 and 646,000 of those infected die.

Social distancing 

The term that has changed daily life for at least a quarter of the world's population living under lockdown refers to maintaining a distance between individuals or avoiding direct contact in public places due to the coronavirus outbreak. The aim is to limit exposure and prevent the spread of infection, but in countries and communities where people live in close quarters, social distancing can be almost impossible.


Some people naturally transmit infections at a higher rate than others. There is no definitive answer as to why this happens but according to a statistical pattern known as the 20/80 rule, about one in five people transmit infections to far more people than the average person does.

Swab test v antibody test

A swab test is taken from the back of the throat or nasal passage and is used to diagnose bacterial infections. Antibody tests, also called serology tests, are done by collecting blood samples and analysing them for antibodies created by the body to fight the virus. Both forms of testing are being used to detect the virus.

Zoonotic disease

These are transmitted between animals and people by harmful germs like viruses, bacterial, parasites and fungi. They can be spread in multiple ways, including via food, water, direct contact, surface contact or insects. Examples include MERS, which has been linked to camels but may have originated in bats, SARS, which is believed to have originated in Chinese horseshoe bats before spreading to other animals, perhaps civet cats, and now Covid-19, which may also have originated in bats and jumped to humans via pangolins, although it's too early to know at this stage.