As the COVID-19 pandemic continues to wreak havoc across the globe, efforts to find a vaccine that can prevent the disease continue to ramp up. According to the World Health Organization (WHO), there are now roughly 70 potential vaccines for SARS-CoV-2, the coronavirus that causes COVID-19, in development. Three of those vaccines are already in clinical trials, among them, Moderna's (NASDAQ:MRNA) candidate.

The National Institutes of Health is currently leading a phase 1 clinical trial for Moderna's potential vaccine. The trial will involve 45 healthy adult volunteers, each of whom will receive two doses of the vaccine about a month apart.  This trial will test the safety of the vaccine, its immunogenicity -- which refers to its ability to trigger an immune response in the body -- and the amount that causes expected side effects. As an early-stage trial, however, it will not attempt to gauge the vaccine's efficacy. 

Face mask with COVID-19 written on it.

Image Source: Getty Images.

CanSino Biologics, a China-based company that focuses on vaccine development, currently has the candidate that is furthest advanced in the trial process. It recently started a phase 2 clinical trial for Ad5-nCoV, its investigational SARS-CoV-2 vaccine. This trial will involve 500 adults who will be divided into three groups. Members of the first group, comprised of 250 people, will receive what it describes as a "middle dose" of Ad5-nCoV, while those in the second group of 125 people will receive a "low dose." The 125 people in the third group will receive placebos. The trial will test the safety and immunogenicity of the vaccine.

Although the efforts of biotechnology companies to develop a vaccine that could prevent COVID-19 are commendable, it isn't time to celebrate just yet. Despite the large number of vaccine candidates currently in development, it will likely take a year or more for researchers to determine if any of them are effective enough to be given to the public at large. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.