On Wednesday, Maryland-based vaccine manufacturer Novavax released preliminary results from an early clinical phase study of its combination Covid/flu vaccine. The results found that the combination vaccine produced immune responses in patients that were comparable to those of its standalone flu and Covid vaccines. The company also found the vaccine formulation to be safe, with mostly mild side effects.

“We’re encouraged by these data and the potential path forward for a combination Covid-19-influenza vaccine as well as stand-alone vaccines for influenza and Covid-19,” Gregory Glenn, Novavax’s president of R&D said in a statement.

Novavax’s vaccine differs from the mRNA vaccines developed by Pfizer, BioNTech and Moderna. Its vaccines use nanoparticles that mimic proteins from the coronavirus or influenza virus (or both, in the case of the combination vaccine). The nanoparticles are injected into patients along with an adjuvant, which is a chemical that helps stimulate the immune system, which causes the patients to develop antibodies against Covid and flu.

The company’s flu vaccine is currently in phase 3 trials. At a media briefing on Wednesday morning, Novavax’s chief medical officer Filip Dubovsky said data from those trials so far show higher antibody responses for patients with Novavax’s vaccine against multiple strains of flu compared to patients who received an approved flu vaccine. Complete efficacy data was not presented, but Dubovsky highlighted similarly high antibody responses against H3N2 flu strains, which existing vaccines have low efficacy against.

Novavax’s Covid vaccine has been authorized for use in over 40 countries around the world, including the EU and most recently Japan. The company applied for emergency authorization with the FDA in January. Although the stock has been trending downward as Covid restrictions continue to lift in most places around the world, Jefferies analysts Roger Song and Xiangyu Ma thing wrote in a report Tuesday that concerns for the company’s long-term prospects are “0overstated,” as they see Covid becoming “an endemic disease requiring effective/tolderated regular vaccination.”

The next step for the combination Covid/flu vaccine will be a phase 2 clinical trial, which Dubovsky says should begin by the end of this year. That trial will be aimed towards optimizing the right dose for the Covid and flu antigens, as well as the right dose for the adjuvant. Following a successful phase 2, a phase 3 trial would be timed for a flu season, hopefully in 2023, though Dubovsky admits this may depend on what the current Covid situation looks like, as Covid mitigation measures have slowed down the circulation of influenza for the past two years.

For Dubovsky, the key advantage of the combination vaccine is that it requires less material than two separate shots would. So if the trials pan out and the combination vaccine goes on the market, he says, that “allows us to manufacture many more doses so we can reach more lives.”