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Development of the COVID-19 vaccine


Content Reviewers:

Rishi Desai, MD, MPH

It seems like the whole world is holding its breath for the COVID19 vaccine.

But you might be wondering, how do we even go about making the COVID19 vaccine?

There are two main goals in vaccine development: First, the vaccine needs to be safe to administer to the general population.

Second, the vaccine needs to be efficacious against the pathogen, for instance a virus.

There are a couple ways to identify that - by seeing if it produces a significant immune response to the virus or by seeing if it reduces the chance of getting the disease itself.

Before a candidate vaccine even begins being administered to humans, it goes through extensive animal testing, typically using lab mice.

In this phase researchers are looking for side effects within the mice, which can range from mild skin irritation at the site of injection, to death.

Researchers also take blood samples from the mice over the next several days to weeks.

Researchers measure the blood antibody levels of the mice, and specifically look for antibodies being produced that would combat the virus.

A sufficient number of antibodies being produced after the vaccine is administered is a promising result.

Sometimes mice are given the virus to see if having the vaccine prevents them from getting the disease.

If there are no significant negative side effects and there’s evidence of vaccine efficacy, the vaccine can move to clinical trials.

Clinical trials are broken down in three phases, and are designed to measure both the safety of the candidate vaccine and the immune response, just like in mice.

In all of these phases, humans are given the candidate vaccine, and others are given a placebo with the goal to help make it easier to compare the efficaciousness of the vaccine.

Healthy adults are usually chosen for these studies because the goal is to ensure that they are least likely to develop a serious problem from the vaccine and so that if they do develop a health issue, it’s most likely from the vaccine and not from an underlying condition.