COVID-19 GLOSSARY

Bookmark this resource to help you understand common terms associated with the pandemic.

Pacific Science Center's

COVID-19 Glossary

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SARS-CoV-2

Exponential growth

Asymptomatic

Virus

Vaccine

Pandemic

Infectious

Immunity

COVID-19

Coronavirus

Contagious

Herd immunity

Contact tracing

Antibody

L-Z

Exponential growth

Asymptomatic

Infectious

Immunity

COVID-19

Coronavirus

Contagious

Serology

RNA

R0

PPE

Mutation

Pandemic

SARS-CoV-2

Vaccine

Virus

A-K

‘What immunity to Covid-19 might actually mean’ Vox article

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Antibodies are proteins your immune system produces to protect you from disease. They fight and neutralize harmful substances and organisms, such as viruses and bacteria. Once activated, antibodies guard against new exposure to substances or organisms like the one that triggered them, and they can remain active for different amounts of time. This means antibodies can increase your immunity against a specific invader, either temporarily or long-term.

Antibody

‘Spreading COVID-19 without symptoms’ Vox article

‘Sick and symptomless’ PBS News Hour video

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A person who is asymptomatic becomes infected with the virus, but never shows symptoms of the disease. When experts say an asymptomatic person is contagious, that also includes people who are pre-symptomatic – those who have contracted the virus and will later show symptoms, but currently appear healthy. The important part is the same whether someone is asymptomatic or pre-symptomatic: this coronavirus can be spread by someone who does not appear to be sick.

Asymptomatic

‘How much does it take to make you sick’ STAT News article

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When a disease is contagious, that means it can be transmitted from one person to another. When a person is described this way, it means they have a contagious disease.

Contagious

‘Why you might now get a phone call to tell you you’ve been exposed to the coronavirus’ Seattle Times article

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Contact tracing is an essential disease control method in which healthcare professionals help a patient to recall each person they may have come into contact with while contagious. The professionals then work to warn each person that they may have been exposed to the contagious disease, and provide them with information, resources, and support.

Contact tracing

‘Coronaviruses’ National Foundation for Infectious Diseases overview

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Coronaviruses, named for their crown-like appearance, make up a family of RNA viruses that cause diseases in birds and mammals. The diseases they cause in humans are usually respiratory ailments, but can include other symptoms.

Coronavirus

‘What experts are learning about symptoms’ NPR article

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COVID-19 is an infectious, contagious disease caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 can include fever, a dry cough, and difficulty breathing. There are other symptoms, some of which may not yet be known, and some people recover without exhibiting symptoms at all.

COVID-19

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‘Exponential growth for COVID-19’ Oxford mathematician video

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Exponential growth means the growth rate increases along with the quantity – the more of something there is, the faster the number will grow. For example, when a bacterial cell splits in half, each new cell will also split. You end up with four, which also each split in half, so now there are eight, and so on. Similarly, when a person gets COVID-19, they can infect multiple people, who will each also infect multiple people, unless the first person avoids all human contact.

Exponentialgrowth

‘What Is Herd Immunity’ Gavi infographic

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Herd immunity, sometimes called community immunity, occurs when so many members of a population develop immunity to a disease that the disease can no longer easily spread. If a disease can’t infect most of the population, then it has a much smaller chance of reaching the people it could infect, and a lot of cases of illness are prevented. Herd immunity can occur if a large number of people have already experienced the illness and developed immunity. When a vaccine is available, herd immunity is able to develop without people actually getting sick first. The vaccinated people become immune, which protects the members of the population that can’t be vaccinated due to factors such as age or a weakened immune system.

Herd immunity

‘What immunity to COVID-19 means’Scientific American article

‘Antibodies, immunity, and COVID-19’ STAT News video

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Some people are immunocompromised, meaning their immune systems aren’t strong enough to fight off diseases. They are more likely to get sick, and when they do get sick, it’s more likely to be serious. One way to protect them is through herd immunity. Herd immunity refers to a group or community having enough resistant members to greatly reduce the spread of a disease. When enough community members have been vaccinated or developed immunity after surviving an illness, it becomes harder for the disease to find new hosts, and the number of infected people is greatly reduced.

Immunity refers to your body’s ability to resist diseases. Your immune system works to fight off illness. Active immunity occurs when you recover from an illness or get vaccinated; your body develops resistance to that disease, and it can’t make you sick again. That resistance can be temporary or permanent, depending on the disease.

Immunity

‘Infectious diseases’ Mayo Clinic overview

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An infectious disease is caused by bacteria, viruses, and other germs. Some infectious diseases can be spread to humans from animals, food, water, or another part of their environment. Some infectious diseases can also be spread person-to-person. In this case, the disease is also contagious.

Infectious

‘How Coronavirus Mutates and Spreads’ New York Times article

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Every virus goes through mutations, or changes. Some of these mutations make a virus stronger or more contagious, some are minor enough to be insignificant, and others can actually weaken the virus and slow it down. Coronaviruses like SARS-CoV-2 are RNA viruses, which mutate more often than DNA viruses. It’s a normal, expected, and frequent part of their lifecycle, and disease experts are able to monitor and study the mutations to learn more about the disease and how to combat it.

Mutation

‘What does ‘pandemic’ mean for COVID-19’ Guardian article

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A pandemic is an outbreak of a disease on a global scale. The CDC explains that an outbreak is the same as an epidemic: an unexpectedly large number of cases of a specific disease within a given period of time, either in a certain area or among a specific group of people. When an outbreak becomes a pandemic, there is an unexpected number of cases of a disease among the entire global community.

Pandemic

‘Personal Protective Equipment for COVID-19 Care’ Rush University Medical Center Video

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PPE stands for Personal Protective Equipment. PPE for different jobs can include masks, gloves, helmets, safety goggles, boots, respirators, fireproof materials, chemical-resistant materials, and more. When dealing with infectious diseases such as COVID-19, healthcare professionals wear a variety of PPE that creates a barrier to keep out the virus while still allowing the wearer to move, breathe, and perform necessary tasks.

PPE

‘What do R1 and R0 Infection Rate Numbers Mean and How Do They Relate To Coronavirus?’ Newsweek article

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R0 (pronounced “R-naught”) is a mathematical concept referring to a disease’s reproductive rate. The R0 value tells you the average number of people that one person with the disease will infect. A value of R5 would mean an average of five new people would be infected by each person who already has the disease. If a disease’s R value is R1 or higher, that means each patient is likely to infect at least one person, and the disease will spread. The higher an R value, the faster a disease will spread if a vaccine doesn’t exist. Human behavior can affect a disease’s R0. For example, the R0 for the measles is between R12 and R18 when left untreated, but in vaccinated communities, it’s less than R1.

R0

‘COVID-19: What’s RNA research got to do with it?’ University of Rochester Newscenter article

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RNA, or ribonucleic acid, is a nucleic acid (like DNA) that exists in all living cells. It serves important functions, such as sending messages throughout our body. It has one more oxygen atom than DNA, and is therefore less stable than DNA, promoting easy changes. RNA’s unstable nature is a benefit for organisms that need to change rapidly – such as viruses. An RNA virus can generally evolve faster than a DNA virus, which helps it to survive even as an immune system begins to fight it off.

RNA

‘How coronavirus hijacks your cells’ New York Times infographic

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SARS-CoV-2

SARS-CoV-2 is the specific coronavirus that causes the disease known as COVID-19. It’s also called “the novel coronavirus,” which just means the new coronavirus. This separates it from other coronaviruses, which cause diseases ranging from the common cold to SARS.

‘What is serological testing?’ MIT Technology Review article

‘Can antibody tests tell if you're immune to COVID-19?’ Livescience article

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Serology

Serology measures antibodies and related properties in blood serum. If a person has had a disease – for example, COVID-19 – antibodies against that disease should be present in their blood. Serological testing is an important step in answering a number of questions, including how widespread the disease is, how common it is to be asymptomatic, and what level of immunity may develop. Understanding immunity to COVID-19 is crucial to the development an effective vaccine.

‘How vaccines work’ Pacific Science Center exhibit panel

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Vaccines contain dead or weakened germs from the same disease they protect you against. In some cases, a vaccine only includes part of the germ. When a virus infects you with a disease, your immune system produces antibodies to protect you. With some diseases, once your body produces those antibodies, you become immune from getting the same disease in the future. A vaccine triggers that same protective response in your immune system, but by using dead, weakened, or partial disease germs, it lets you skip past the illness and go straight to the immunity.

Vaccine

‘What is a virus, part two, coronavirus’Stanford Scope blog entry

‘What is a virus, part one, the basics’ Stanford Scope blog entry

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A virus is a microscopic parasite, generally much smaller than bacteria. Viruses make copies of themselves within the cells of an organism, sometimes infecting the host (the body housing the virus) with a disease. Different viruses enter the body in different ways, including through bodily fluids, open wounds, or cavities such as the eyes, nose, and mouth.

Virus

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As more people become infected with COVID-19, the rate at which people become infected continues to increase, unless people stay home.

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