A vial of SARS-CoV2 COVID-19 vaccine in a medical research laboratory

The National Institutes of Health is launching a phase 2 clinical trial to help determine which vaccine combos can provide a broader immune response in adults who have already had a series of COVID-19 vaccinations.

Booster vaccinations are effective in shoring up the waning efficacy of the initial shots in the face of the omicron variants. But protection gained from the currently recommended mRNA vaccine boosters lasts only about four months. Federal health officials are therefore preparing for the possibility that future variants will evade these drugs’ protection altogether. 

“[P]redicting if, when and where new COVID-19 variants will emerge and how they will affect the population, remains challenging,” officials announced Thursday. 

“We are looking beyond the omicron variant to determine the best strategy to protect against future variants,” said Anthony Fauci, M.D., director of the NIH’s National Institute for Allergy and Infectious Diseases, which sponsored the study.

“This trial will help us understand if we can use prototype and variant vaccines alone or together to shift immune responses to cover existing and emerging COVID-19 variants,” he said.

Future vaccine recommendations

Investigators will gather data on the immune responses induced by the existing and variant vaccine candidates. These include new vaccines that have been developed to target omicron specifically, and bivalent vaccines, which target two SARS-CoV-2 variants. This will help inform future vaccine recommendations, NIH said. 

The study, known as the COVID-19 Variant Immunologic Landscape (COVAIL) trial, will be conducted in collaboration with Moderna, which makes one of the two federally approved mRNA vaccines in the United States. The trial will enroll more participants as needed to “evaluate additional vaccine platforms and variant vaccines from other manufacturers,” NIH and NIAID reported.