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A new vaccine from Sanofi and GlaxoSmithKline is one of two being reviewed by federal regulators. Jeremy Moeller/Getty Images
  • Novavax has asked federal regulators for emergency use authorization for its new COVID-19 vaccine.
  • Meanwhile, Sanofi and GlaxoSmithKline are requesting full approval for their COVID-19 vaccine.
  • Both vaccines use older technology than the mRNA vaccines currently in use.
  • Experts say the new vaccines could help convince hesitant people to get vaccinated.
  • They also note the new vaccines could help worldwide since they don’t need to be stored at extremely low temperatures.

Two new COVID-19 vaccines could help boost the number of people getting vaccinated because they rely on older, more familiar technology to protect against the novel coronavirus.

The pharmaceutical company Novavax is currently seeking emergency use authorization (EUA) from the Food and Drug Administration (FDA) for its new vaccine, which already has been approved for use in Canada and other countries.

Another new vaccine, under development by Sanofi and GlaxoSmithKline (GSK), recently completed phase 3 clinical trials and is being submitted for full approval from the FDA.

Unlike the Moderna and Pfizer-BioNTech vaccines, which use cutting-edge mRNA technology to prompt an immune response to coronavirus infections, both Novavax and Sanofi-GSK are protein adjuvant vaccines and use technology similar to that in the flu vaccine.

Rather than using genetic information to alert the immune system like an mRNA vaccine, Novavax and Sanofi-GSK tie a bit of harmless coronavirus spike protein to an adjuvant, an ingredient that alerts the immune system.

Using this well-known vaccine technology may prompt people who are hesitant or anti-vaccine to get inoculated, said Philip Felgner, PhD, director of the University of California at Irvine’s Vaccine Research and Development Center.

In the case of Novavax, the adjuvant is derived from tree bark.

The Sanofi-GSK vaccine uses an adjuvant called AS03 based on an oil called squalene, originally sourced from sharks.

“We’ve had decades of experience with AS03 and millions of people who have been vaccinated with it,” Felgner told Healthline.

Adjuvant vaccines have been around since the 1950s, which also could reassure “those who are concerned about safety issues, even though the mRNA vaccines are extremely safe,” Dr. Bob Bollinger, a professor of infectious diseases at Johns Hopkins University School of Medicine in Maryland and a founding member of emocha Health.

“If it persuades people who are hesitant to get vaccinated, that’s a good thing,” he told Healthline.

The fact that Novavax is applying for an EUA from the FDA may not satisfy some vaccine-hesitant people, but the new vaccine from Sanofi-GSK checks the boxes of being a non-mRNA vaccine and having gone through the full FDA approval process.

In February, Sanofi-GSK announced they had completed phase 3 clinical trials on their vaccine and will be submitting it to FDA for approval.

“It’s been under development since the beginning [of the pandemic],” said Felgner, who also pointed out that without the FDA’s emergency authorization process, there still wouldn’t be any COVID-19 vaccines available to the public.

In a statement, Sanofi-GSK said their research showed the vaccine was 100 percent effective against severe COVID-19 disease and hospitalization, 75 percent effective against moderate or severe COVID-19 disease, and nearly 58 percent effective against any symptomatic COVID-19 disease.

“It’s very comparable to mRNA vaccines in terms of efficacy and safety,” said Felgner.

According to data from the U.S. Census Bureau, concern about side effects is the top reason cited by U.S. adults who have not been vaccinated.

Distrust of the vaccines is the second-most common reason for vaccine hesitancy, followed by a general distrust of the government.

Felgner said the new vaccines likely won’t address all concerns about the side effects of the COVID-19 vaccine.

Among other things, adjuvants are known to cause pain at the site of injection, which is the most common side effect associated with the COVID-19 shots.

Felgner also noted that while having a vaccine that has gone through the entire FDA approval process will be valuable, the number of participants used by Sanofi-GSK in their clinical trials pales in comparison to the billions of people who have received mRNA vaccines.

Bollinger said the new vaccines may chip away at the number of Americans who have refused to be vaccinated up to this point, but their biggest value is likely to be global.

Unlike the mRNA vaccines, which have to be stored for shipment at temperatures as low as -130°F, the new vaccines require less extreme refrigeration.

“They’re much easier to produce, lower cost, and more easily transportable,” said Bollinger. “They’re really going to be useful in getting more of the world vaccinated, which is to everyone’s benefit.”