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How do we develop a new vaccine?

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After lots of laboratory work, how do we[br]know it is ready to get tested in humans?

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And then, how do we know [br]whether or not it works?

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We test new vaccines in clinical trials to[br]determine that they're both safe and effective

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before they get licensed in the US.

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Stick with us, this is going to be interesting.

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And, although this applies[br]to all kinds of drugs and vaccines,

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we're going to focus here on vaccines used for[br]prevention of a specific type of infection.

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The first thing to know is that a lot of[br]testing is done before a vaccine

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ever gets tested in humans.

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There is a long process of development in[br]a laboratory,

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and testing, both for safety and for [br]protection, in animal studies.

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After we have a vaccine that looks both safe[br]and promising in preventing infection

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in a laboratory, we begin testing in humans.

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Because we don't know whether or not[br]the vaccine will work,

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we begin a very structured set of studies[br]called clinical trials.

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These studies involve healthy volunteers,[br]who are told in detail about how and why

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this vaccine is being tested, and about any[br]potential harm.

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This educational process is a process[br]called informed consent,

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and goes on before and during the trial.

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There's a continual discussion that happens[br]between the researchers

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and the study volunteers.

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Describing the study, informing the[br]volunteers about any new information

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that happens at any time during the study,

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and answering all questions that[br]the volunteers have.

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The study staff also determine whether[br]the volunteer meets all the eligibility

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criteria to participate, which involves[br]physical exams and blood tests.

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Next, we start what is called a ramdomized,[br]double-blinded clinical trial.

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What that means is that after volunteers[br]enrol in a study,

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a computer randomly decides whether they[br]will get the vaccine

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or whether they will get the placebo,

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which is usually just salt water.

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We do this to be able to separate outside[br]effects that are due to the vaccine

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from those that are just happening to[br]people in a community at the same time,

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like the rate of cold symptoms,[br]or headaches.

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And, we double-blind, meaning neither[br]the participant nor the study staff

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know who is getting which type of injection.

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That prevents both the volunteers and the[br]staff from over or under reporting symptoms.

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We advise participants to tell us about[br]everything that is happening to them.

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Before a vaccine is licensed by the[br]US food and drug administration,

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it usually goes through 3 phases of[br]clinical trials,

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each of which has a specific purpose.

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Phase 1 trials, which can last up to 2 years,

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compare the safety - does the vaccine[br]cause any side effects,

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and tolerability - does the injection hurt,[br]and for how long?

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In this phase of studies, scientists are[br]also gathering information about

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the body's immune response to the vaccine,

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to see whether it is a promising approach[br]to preventing this specific infection.

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Phase 1 trials do not determine whether[br]or not the study product is actually doing

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what we hope it will do.

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Phase 2 trials, which can last[br]longer than 2 years,

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will confirm the safety in a larger group[br]of volunteers,

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and focus on the best dose and the best[br]timing of vaccinations to produce

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the strongest immune response.

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Promising vaccines that are safe and[br]generate a strong immune response

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move into phase 3 trials.

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These are the largest trials, and compare[br]the rate of infection in the vaccine and

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placebo groups.

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This will tell us whether the vaccine is[br]able to prevent infection,

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and, if so, if it is effective in all of[br]the volunteers, or only a sub-group,

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like younger volunteers, or women.

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Along with the safety data that is collected[br]in all phases of vaccine studies,

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this efficacy data is used by the FDA to[br]decide if the vaccine should be licensed,

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and, if so, for whom it is recommended.

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In the best case scenario, it could take[br]6-10 years for a promising vaccine to move

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from phase 1 testing[br]to real world distribution.

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Often it takes longer.

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The clinical trials are absolutely [br]necessary to determine that a vaccine

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is safe and effective in preventing [br]new infections.

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This video has been provided to you by[br]Youreka science, in collaboration with

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BridgeHIV.

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