Single-Shot Vaccine Under Development Could Protect Against Flu, COVID-19, and RSV

A single-shot vaccine targeting influenza, COVID-19, and respiratory syncytial virus (RSV) is being developed by researchers, aiming to address the “tripledemic” of respiratory illnesses that has strained healthcare systems since 2022, according to a study published in Science Advances. The vaccine, developed using a platform called CoPoP, triggered protective immunity against all three viruses in animal models, with antibody responses comparable to those of single-virus vaccines, researchers reported.

How Does the CoPoP Platform Work?

The CoPoP platform, developed over a decade by Jonathan Lovell, a biomedical engineering professor at the University at Buffalo, uses tiny spherical nanoparticles made of cobalt and porphyrin with a phospholipid outer shell. Viral proteins are attached to these nanoparticles via histidine tags, which bond with cobalt ions. Once administered, the proteins train the immune system to recognize and combat the viruses. For this study, the platform incorporated five viral proteins—three from influenza, one from SARS-CoV-2, and one from RSV—alongside immune-boosting adjuvants PHAD and QS-21.

“CoPoP is a flexible formulation that allows multiple viral proteins to be incorporated at once,” Lovell said. The platform differs from mRNA-based COVID-19 vaccines, which use genetic instructions rather than viral proteins.

Why This Vaccine Matters

The 2023–2024 respiratory virus season saw approximately 1 million combined hospitalizations in the U.S. due to the tripledemic, according to the study. Despite the risks, vaccination rates remain low: only 35% of Americans aged 75 and older had received a flu vaccine as of November 2024, while 18% had received a COVID-19 vaccine and 40% an RSV vaccine, per data.

“Many people skip one or more recommended vaccines due to inconvenience,” said coauthor Bruce Davidson, an anesthesiology research professor at UB. Replacing multiple shots with a single annual vaccine could improve immunization rates, he added.

Challenges and Next Steps

The study found no evidence of immune interference, where one vaccine component weakens the response to another. However, researchers caution that further studies are needed to evaluate potential interactions under different dosing conditions. Lovell noted the platform’s potential to expand protection to additional respiratory viruses in the future.

The CoPoP-based vaccine has previously advanced through phase 2 and phase 3 trials in South Korea and the Philippines as a standalone COVID-19 candidate, developed by UB spinoff POP Biotechnologies, Inc., in partnership with EuBiologics.

What’s Next for the Triple Vaccine?

While the study demonstrates promise in animal models, human trials are the next critical step. The National Institutes of Health (NIH) and McGill University funded