Moderna's shares have more than tripled in value so far this year. BioNTech has been an even bigger winner for investors. Buying and holding the stocks of leading COVID-19 vaccine makers has turned out to be a pretty good strategy.

But there's one vaccine stock that has outperformed them all in 2021. Shares of Ocugen (OCGN 1.53%) have skyrocketed close to 550% year to date. Here's why the stock will probably soar even more tomorrow -- but shouldn't. 

COVID-19 vaccine vial and a syringe with needle on top of a stock chart going up.

Image source: Getty Images.

A likely win for Covaxin

Tomorrow -- Nov. 3, 2021 -- a World Health Organization (WHO) technical advisory group is scheduled to meet to review the data for COVID-19 vaccine Covaxin for a potential Emergency Use Listing (EUL). Bharat Biotech, the developer of Covaxin, first officially indicated its interest in receiving EUL for the vaccine back in April 2021. 

The technical advisory group has already met previously about Covaxin. However, the group requested some clarifications from Bharat. But the meeting on Wednesday of this week will be a final assessment of the vaccine's qualifications in receiving EUL.

There's no way to know for sure in advance what the technical advisory group's recommendation will be. The smart money, though, is on Covaxin winning EUL.

Covaxin has already won Emergency Use Authorization (EUA) in India, where Bharat is based. Obtaining EUL would clear the way for the vaccine to be distributed to nearly 200 countries that participate in the COVAX Facility, which aims to make COVID-19 vaccines available across the world. 

No immediate benefit for Ocugen

Ocugen shares skyrocketed more than 20% on the day of the first WHO technical advisory group meeting. There's no reason to doubt that history will repeat itself this week. However, there's also no good reason for the stock to jump.

The fact of the matter is that EUL for Covaxin doesn't immediately benefit Ocugen. Sure, the company has marketing rights to the vaccine in the U.S. and Canada. Neither of those countries will receive vaccines as part of the COVAX Facility, though. They're both donors to the initiative.

So why might Ocugen's shares soar tomorrow anyway? It's important to understand the intense interest in the stock among online investing communities. At the same time, the stock has attracted plenty of short-sellers. As of Oct. 15, 2021, close to 29.5% of Ocugen's stock float was sold short

Because of these two factors, any perceived good news for Ocugen is likely to light a fire beneath its stock. That can happen even when the good news doesn't directly help the company, as is the case with potential EUL for Covaxin.

What really matters

What really matters the most for Ocugen right now is winning authorization for Covaxin in Canada. The company has completed its submission to Health Canada and awaits a decision.

The second most important thing that matters for Ocugen is moving forward with a pivotal phase 3 study of Covaxin in the U.S. Ocugen announced last week that it has filed an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA) to begin this study. 

However, the FDA must first give a green light for the phase 3 study. Ocugen plans to only enroll several hundred participants who have either not been vaccinated or who have received two doses of a messenger RNA vaccine at least six months earlier.

This study would be far smaller than the pivotal studies of other COVID-19 vaccines that have been authorized or approved in the U.S. Ocugen hopes that the FDA will agree that the relatively small study will be sufficient to demonstrate similarity with results obtained in a larger study conducted in India with 25,798 participants.

If the FDA allows Ocugen's study to move forward, it would provide a good reason for investors to get excited. The company thinks that it could wrap up the study in the first half of 2022. That could set the stage for Ocugen to file for full FDA approval of Covaxin shortly afterward.