Some experts thought that the warmer temperatures of summer would lead to a slowing of the spread of COVID-19. But summer has arrived -- and the numbers of COVID-19 cases are rising sharply, especially in several states with warmer climates. 

Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said in May, "We all have to confront the fact there's not a magic bullet, short of a vaccine, that's going to make this go away." It's looking more and more like Osterholm was right.

But Osterholm's comment acknowledges that a vaccine could be that magic bullet that many anxiously await. When will you be able to get a coronavirus vaccine? Here's what you need to know.

Healthcare professional holding cotton swab on a patient's arm and holding a syringe

Image source: Getty Images.

Where things stand now

More than 140 experimental vaccines for immunization against the novel coronavirus are being researched across the world right now, according to the World Health Organization. However, most of those vaccines are only in preclinical testing. Currently, there are 16 COVID-19 vaccines in clinical studies.

The leader of the pack, at least in terms of clinical progression, is the vaccine being developed by the University of Oxford and AstraZeneca. This vaccine is in a phase 3 clinical study.

Several other COVID-19 vaccine candidates are close behind the Oxford/AstraZeneca vaccine. Two Chinese drugmakers, Cansino Biologics and Sinovac, are evaluating their respective coronavirus vaccine candidates in phase 2 clinical trials. U.S.-based biotech Moderna (NASDAQ:MRNA) also has a COVID-19 vaccine candidate in phase 2 testing and has already received a green light from the Food and Drug Administration (FDA) to begin a phase 3 clinical study of its COVID-19 vaccine in July.

Another Chinese pharmaceutical company, Sinopharm, has two vaccine candidates in phase 1/2 clinical testing. German biotech BioNTech and its partner, Pfizer (NYSE:PFE), have a phase 1/2 clinical study in progress evaluating four messenger RNA (mRNA) COVID-19 vaccine candidates. Novavax also has a phase 1/2 clinical trial under way for its experimental COVID-19 vaccine.

Eight other COVID-19 vaccine candidates are in phase 1 clinical studies. They will be joined soon by Johnson & Johnson, which plans to begin an early stage clinical trial of its COVID-19 vaccine candidate in late July.

What's next

Regulatory agencies, including the FDA, require vaccine candidates to successfully complete three phases of clinical testing before a drugmaker can file for approval. Data from the clinical studies is reviewed by experts within the regulatory agencies to determine if the vaccine is safe enough and effective enough to be able to be marketed.

The farther along a vaccine candidate progresses in the clinical testing phases, the more likely it is to win regulatory approval. Biotechnology trade organization BIO reviewed data from 2006 through 2015 to determine the following probabilities for FDA approval of a vaccine:

Testing Phase Completed Probability of FDA Approval
Phase 1 16.2%
Phase 2 24.4%
Phase 3 74.3%

Data source: BIO. 

Over the next few months, some of the COVID-19 vaccines in clinical testing will likely advance to the next phase. It's also possible that some could prove to be ineffective or cause adverse reactions that are severe enough that they can't move forward. In the meantime, several drugmakers are ramping up their capacity to produce large quantities of their COVID-19 vaccines even before regulatory approvals are obtained. 

Two COVID-19 vaccine bottles upright with two on their sides

Image source: Getty Images.

Most likely availability

Typically, vaccines can take several years to move through clinical testing and win regulatory approval. However, the COVID-19 pandemic could disrupt the normal timelines.

Executives in the healthcare sector are optimistic. Moderna CEO Stephane Bancel has stated that his company could be ready to submit its COVID-19 vaccine for approval "toward the end of the year or early next year." Pfizer CEO Albert Bourla has challenged his team "to have millions of doses of vaccine in the hands of vulnerable populations before the end of the year," according to the company's Chief Scientific Officer Mikael Dolsten. 

What do experts outside of the biopharmaceutical industry think? There are mixed opinions. Some think that it will be practically impossible for a COVID-19 vaccine to be ready by early 2021. Others are cautiously optimistic. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, believes that a COVID-19 vaccine could potentially be ready either by the end of 2020 or in early 2021.

Perhaps the best prediction at this point is that one or more COVID-19 vaccines could be available sometime next year -- if all goes well in clinical testing. The safer bet would be for later in 2021, but it's possible that you could get a coronavirus vaccine in the first half of the year.

There's another key question in addition to when a COVID-19 vaccine will be available: How effective will the vaccines be? Moderna's Bancel thinks his company's COVID-19 vaccine has an 80% to 90% chance of success. But his definition of success is efficacy of more than 50%. Using his target, even a successful vaccine could still leave nearly half of the population vulnerable to being infected by the novel coronavirus. 

Regardless of how quickly a vaccine is ready, it might not be the magic bullet that many hope for.

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.