Predictions of a COVID-19 wave in the fall make another booster vaccine campaign likely, but questions abound about how the virus will continue to evolve and what protections a new vaccine could offer.
Several vaccine manufacturers are struggling to develop formulas that take into account the more infectious Omicron variant that now drives cases, while policymakers are laying the groundwork for another large-scale vaccine bombing.
Much of this depends on expectations that the so-called bivalent vaccine may curb a potential future increase as the flu season begins and relieve pressure on a tense healthcare system.
Currently available COVID-19 vaccines are monovalent, meaning they adapt only to the new original coronavirus.
The proposed bivalent vaccines target specific mutations in the ear protein observed in both the older strain and the newer Omicron strain, which has generated several more infectious subvariants that dominate current infections.
Last week, the National Immunization Advisory Committee released interim guidelines for an fall program that it said were most important for older adults and those at higher risk for severe COVID-19.
He also noted that while vaccine protection against symptomatic disease decreases over time, protection against serious disease remains better.
In the United States, Food and Drug Administration advisers said last week that fall reinforcements should contain some version of the Omicron variant.
The NACI did not ask for a specific formulation while waiting for more evidence, but said a bivalent injection could encourage absorption in the fall.