This is a recurring column on clinical research in the early stages of development, which is referred to as phase 1. These are treatments being used for the first time in a small number of human patients to determine safety, dosing and general pharmacological activity.

The acceleration of clinical trials for COVID-19 vaccine candidates has raised concerns that conclusions will be difficult to draw from study results, particularly as early-stage research blends into larger-scale trials, experts say.

On top of the fundamental rush for a working vaccine, several of the top contenders to be first to market are new technologies — like mRNA vaccines from Moderna Inc. and Pfizer Inc.-BioNTech SE or non-replicating vectors from AstraZeneca PLC. Such vaccines hold promise but lack the tried-and-true nature of more traditional approaches to producing inoculations.

Other manufacturers using these new technologies in earlier stages include Merck & Co. Inc., Inovio Pharmaceuticals Inc., CureVac NV and China's CanSino Biologics Inc.

"With the early stage of vaccines that we're seeing, there's actually very little information about those right now," Gustav Ando, vice president of industry services and life sciences at IHS Markit, told S&P Global Market Intelligence in an interview. "We don't have the clinical data to understand their broader potential in this disease, so all we have to go on right now is the theoretical understanding that the technology and the approach could work."

While the pandemic has accelerated the use of the newer vaccine technologies, it has also led to an inundation of muddy data, what Ando calls "noise."

"There is this very pervasive understanding that some of the early data that we've seen for these vaccines means that they're actually already effective, and they're not," Ando said. "We have no idea whether these are effective at this stage, especially in the most important populations here such as the elderly and minorities."

The traditional approach to vaccines involves killing or modifying a virus to prime a person's immune system to fight off a future infection. The newer vaccines use parts of the virus's own genetic code to stimulate the immune system with proteins associated with a particular pathogen.

"This is really at the cutting edge of vaccine development, and it's all very recently that this technology was pretty much 100% science fiction," Ando said. "What we're talking about here is something that had in the last two or three years made some fairly significant strides, but nothing that was developed or commercialized in the market for any infectious disease."

The benefits of these new technologies are far-reaching, Ando said, as they tend to be easier and safer to develop and scale up to population levels. And they could theoretically lead to stronger immune responses that stay with a person for longer periods of time.

But taking vaccines so quickly from first-in-human trials to large studies of 30,000 patients or more means researchers are unable to step back and draw meaningful conclusions from each step of the process, Ando said.

"What you have had is multiple trials starting at once and overlapping with each other, which does go against most standard clinical trial protocols," Ando said. Early-stage, or phase 1, trials are not meant to demonstrate the effectiveness of a vaccine but rather the safety of the candidate in human bodies, particularly with previously untested technology.

Counterintuitively, the more traditional vaccines — like a candidate from vaccine giants GlaxoSmithKline PLC and Sanofi — are further behind in development despite the experience that developers have with that type of inoculation.

"You'd almost expect that the traditional ways of doing something move faster because they're so well established should in theory be a well-oiled machine that can go much, much quicker," Ando said. "But that's not really the case here in this specific situation simply because the mRNA technology such as it is allows for a very fast-tracked pathway."

Even if results from later trials for the lead candidates — the earliest of which are expected by the end of October — show significant effectiveness, the need for follow-up studies and more nuanced testing would keep vaccines from being widely available until the middle of 2021, Ando said.

The number of vaccines in early trials is heartening because the COVID-19 pandemic will not be ended by just one candidate and requires a multitude of approaches to ensure widespread inoculation, Ando said.

"We need representatives from all of these different technologies in an ideal scenario because each of them bring different benefits to the table," Ando said. "Some of them, it's potential effectiveness, some of them it's safety, and some just pure practicality of distribution and storage — we need that for the sheer capacity to vaccinate so many human beings on Earth and to address a diverse set of needs across countries."