Health Literacy Thesaurus: Medical terms, phrases, references,
and their Plain English equivalents or definitions

I (identical - isolation of ill people)

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identicalsame, exactly the same
illness rate or clinical attack ratenumber of sick people; (Use a ratio like “3 in every 10 New Yorkers are sick” or a percentage like “30 percent of all Floridians are sick.”)
illustrateshow, draw, picture
immediatelyat once, right away
immerseput completely in, completely cover
immune globulinsomething in your blood that helps fight disease
immunewhen your body can protect itself from a disease; protected from
immunitythe body’s ability to keep from getting a disease; protection from disease, ability to fight off an illness
immunizationgetting a vaccine (shot)
immunizeto protect again disease, usually by a shot
immunologicalrelated to the immune system
immunosupressionwhen your body can’t fight disease
immunotherapymedical treatment that helps your body fight off diseases
impedeget in the way, slow
imperativeimportant, pressing, urgent
imperceptiblehard to see, hidden
implementstart, begin
in excess ofmore than
in the absence ofwithout
in the course ofduring, in
in the event ofif
in vitroout of the body, outside the body, laboratory grown, in a test tube
in vivowithin the body, inside the body grown inside animal
inaccuracyerror, mistake, chance that there is a mistake
inactive vaccinea vaccine that uses germs that have been killed
inadvertentlywithout meaning to
inadvisablerisky, not smart, may be dangerous
inapparent infectionwhen you are sick but you don’t feel bad
incidencehow many people get sick
incidencenumber of sick people
incident of national significancenational emergency
incisorsfront teeth, front “biting” teeth
inclementharsh, extreme, dangerous
incorrectwrong, not true, false
increaseadd to, raise
incubation periodthe length of time a disease is in someone’s body before they feel or look sick
indicatesuggest, point to
indicationsign, signal
indigenouslocal to, comes from, native
individualperson, you, man, woman
inexpensivecheap, low cost, low priced
infect diseasespread by germ or virus, to get sick, to make someone sick, to spread a disease
infection controlhow to avoid sickness
infectionillness caused by germs, a sickness you get from germs
infectious agentvirus, germs, something that makes you sick, disease, flu, parasite
infectioussomething that can spread disease
inflamemake hot, red, or swollen; swollen
inflammationswelling, injury, sore
Inflammatory Bowel Diseasedigestive system disease, intestinal problems
infusionput fluids or drugs directly into your blood
ingestioneating, drinking, swallowing
inhalationbreathing, breathing in
inhalebreathe in; take a breath
inhalerbreathing medicine/drug, asthma medicine
inherentnatural, built in, native
inheritacquire, get, obtain, be left
inheritancepassing of traits (such as eye color) from parent to child
inhibitcheck, bar, forbid, stop
initialfirst, earliest, basic
injectionshot, to give medicine by needle, booster, dose
insufficientnot enough, too little, failing, poor
integratecombine with, make part of
intentiongoal, aim, desire, end
internal organsinside parts of your body (heart, lungs, stomach, kidneys, etc.)
interruptstop, break
intrauterine deviceIUD, birth control
intravenous (IV)into your vein; into your blood stream, putting drugs or fluids directly into your blood
investigational vaccinevaccine still being tested
irrefutablecertain, final, obvious, proven
irritablesensitive, complaining, grouchy, testy
irritantbother; pain, pest, problem
isolatea specific type of virus; a specific type of flu
isolation of ill peoplestaying away from people who are sick; keeping sick people at home

Source: CDC Plain Language Thesaurus for Health Communications. Other related materials: Vaccines & Immunizations Glossary; Harvard School of Public Health "Plain Language Glossaries" for asthma, arthritis, and lupus; Medical Library Association "Deciphering Medspeak" for diabetes, stroke, and HIV-AIDS

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