Antibody (antibodies): Proteins the body’s immune system produces that attach to pathogens like viruses and disarm them.
Antiviral drug: A drug specifically designed to fight one or several viruses, which are a common source of infections.
Countermeasure: A drug or vaccine used to fight a particular pathogen.
Diagnostic: A test used to determine what is making a person ill or whether a person has a particular disease or condition. Tests often use blood to look for evidence of infection.
Drug: A chemical or a biological compound that is used to treat or cure a disease or a condition. Some drugs also prevent diseases; for example, Malarone prevents malaria.
Incubation period: The time from when people first become infected until they become sick. This varies by disease. For Ebola, it can be as short as two days and as long as 21, but is most commonly between eight and 10.
Monoclonal antibodies: Specific antibodies. When the body’s defenses kick into action to fight an invading bacteria or virus, it makes a number of different types of antibodies. Sometimes scientists can figure out which are the best at targeting an invader. They grow up (clone) many copies of it to use as a treatment.
Placebo: A fake treatment that should have no medicinal power. It is what drugs or vaccines are tested against in many clinical trials. In a drug study, the placebo might be a sugar pill formulated to look like the pill being tested. In a vaccine study, it would be a shot of salt water.
Prime-boost: A vaccine regimen requiring two (or more) inoculations. The first jab readies or “primes” the immune system to recognize Ebola virus, and the antibody response is “boosted” by a second injection. Some prime-boost regimens involve two doses of the same vaccine. But the Ebola vaccines being studied require two doses of two different vaccines.
Prophylaxis: The technique of using a vaccine or drug to prevent a disease or keep it from becoming severe. When given after someone has been exposed to a disease agent it’s called post-exposure prophylaxis. Prophylaxis means to prevent.
Randomized Controlled Trial (RCT): A type of clinical study that is generally considered to generate the best caliber evidence. Volunteers are randomly assigned to get either the vaccine or drug being tested, or a placebo. If the drug or vaccine works, you should see better survival rates (with a drug) or fewer infections (with a vaccine) among the volunteers that were assigned to get them.
Vaccine: A product that is used to prevent infection. Most vaccines are injected into the muscle or skin, but some are taken by mouth. Vaccines teach the immune system to recognize and fight against a bacterium or virus. When the person is later exposed to that pathogen, the immune systems quickly mounts a response, and prevents it from making the person sick. Some vaccines can also be given after exposure, to prevent or lessen the severity of the illness.
- A primer on clinical trials at www.clinicaltrials.gov, a U.S. government site that hosts a registry of clinical trials that are underway or have been done.
- How New Drugs are Developed and Approved, by the U.S. Food and Drug Administration.
- Seth Berkley, CEO of GAVI (the Vaccine Alliance) explains the difficulties of developing treatments or vaccines for rare diseases.
- The World Health Organization assesses the progress towards Ebola vaccines, drugs and rapid tests.
- Jon Cohen’s article in Science on the early results of the favipiravir study explores the difficulties of trying to test Ebola drugs and the tensions over whether randomized controlled trials are essential or unethical.