> ## Content Index > Fetch the complete content index at: https://www.theamericanquorum.com/llms.txt > Use this file to discover other available public pages before exploring further. # FDA Tells Vaccine Makers to Target Omicron BA.4 and BA.5 in Bivalent COVID-19 Boosters for Fall - URL: https://www.theamericanquorum.com/taq-historical-2022-07-02-healthcare/ - Published: 2022-07-03T03:59:00.000Z - Updated: 2022-07-03T03:59:00.000Z - Description: FDA advised COVID-19 vaccine manufacturers to add an Omicron BA.4/BA.5 component to fall booster formulations after its advisory committee backed updating vaccine strain composition. - Author: Kenneth R. Deans Jr. - Tags: Healthcare, #Import 2026-08-31 14:02 The Food and Drug Administration is asking COVID-19 vaccine manufacturers to redesign fall booster doses around a two-component formulation that retains the original coronavirus strain while adding protection targeted at the rapidly expanding Omicron BA.4 and BA.5 subvariants. The decision marks the clearest U.S. move yet toward treating COVID-19 vaccine composition as something that may need to change as the virus evolves. In a [June 30 update](https://www.fda.gov/vaccines-blood-biologics/update-covid-19-vaccine-booster-composition?ref=theamericanquorum.com), FDA said manufacturers seeking authorization for modified boosters should develop bivalent vaccines combining the original SARS-CoV-2 component with an Omicron BA.4/BA.5 component. The agency is not asking companies to change vaccines used for the primary series, saying the existing formulation continues to provide a foundation of protection against serious outcomes. ## An advisory vote establishes the direction, but FDA selects the specific target The decision followed a June 28 meeting of FDA’s Vaccines and Related Biological Products Advisory Committee. The panel voted in favor of including an Omicron component in booster vaccines intended for use during the coming fall and winter. FDA then made the more specific choice to recommend BA.4 and BA.5 rather than the earlier BA.1 Omicron lineage used in much of the clinical testing conducted so far. An [FDA briefing document](https://www.fda.gov/media/159452/download?ref=theamericanquorum.com) prepared for the meeting described the central problem. Current U.S. vaccines are based on the virus strain that circulated early in the pandemic. They continue to provide meaningful protection against severe disease, especially after booster doses, but Omicron and its sublineages are antigenically different enough that protection against infection and milder symptomatic disease is reduced and wanes over time. FDA said updating vaccine composition is a complex decision because manufacturers must begin producing doses before anyone can know which variant will dominate months later. A fall vaccine therefore has to be selected under uncertainty, balancing current variant trends, immune-response data, manufacturing timelines and the risk that the virus will change again before widespread administration. ## BA.4 and BA.5 are gaining ground faster than the clinical trials can follow The agency’s meeting included a detailed [epidemiology presentation](https://www.fda.gov/media/159494/download?ref=theamericanquorum.com) showing the continuing replacement of earlier Omicron sublineages. BA.2 had displaced BA.1 during the spring, and BA.2.12.1 then grew rapidly in the United States. BA.4 and BA.5 were increasing in proportion by late June, raising the possibility that a vaccine designed around BA.1 could be mismatched to the variants circulating when boosters are actually administered. That creates an unusual regulatory challenge. Clinical trials require time, but the virus can change significantly during the months needed to collect data, review results and manufacture hundreds of millions of doses. FDA is therefore considering how much it can rely on immunogenicity, safety experience with the existing platform and manufacturing comparability rather than requiring large efficacy trials for every strain update. The agency’s approach resembles, in broad concept, the recurring strain-selection process used for influenza vaccines, although SARS-CoV-2 is a different virus with different epidemiology and a much shorter history of population immunity. Regulators are trying to build a process that can respond quickly while preserving confidence in safety and effectiveness. ## Moderna and Pfizer present different versions of the same strategy Manufacturers have already been testing variant-adapted vaccines. Moderna’s [advisory-committee presentation](https://www.fda.gov/media/159492/download?ref=theamericanquorum.com) described mRNA-1273.214, a bivalent candidate combining 25 micrograms of mRNA encoding the original spike protein with 25 micrograms targeting Omicron. The company reported stronger neutralizing-antibody responses against Omicron than a booster of its original vaccine, while maintaining responses against the ancestral strain. Pfizer and BioNTech’s [presentation](https://www.fda.gov/media/159496/download?ref=theamericanquorum.com) similarly evaluated Omicron-modified booster options, including monovalent and bivalent formulations. The companies reported that Omicron-adapted candidates produced higher neutralizing responses against Omicron than another dose of the original vaccine, although the data available at the meeting were centered primarily on BA.1 rather than the now-rising BA.4 and BA.5 sublineages. In a [June 25 release](https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-omicron-adapted-covid-19?ref=theamericanquorum.com), Pfizer and BioNTech said both of their Omicron-adapted candidates generated substantially higher immune responses against Omicron BA.1 than the companies’ current vaccine. They also reported lower neutralization against BA.4 and BA.5 than against BA.1, evidence that helps explain FDA’s preference for directly including the newer subvariants in the fall formulation. ## The fall campaign becomes a manufacturing race The scientific choice now becomes an operational one. Vaccine makers must translate the BA.4/BA.5 recommendation into updated manufacturing, quality testing, regulatory submissions and large-scale production quickly enough to provide doses before an anticipated fall campaign. FDA says companies do not need to stop producing the original vaccine because it will still be used for primary vaccination. A bivalent strategy is intended to preserve the broader immune foundation created by the original vaccine while adding a component better matched to currently circulating Omicron viruses. That could reduce the risk of focusing immunity too narrowly on one recent variant while still improving recognition of strains that have drifted substantially from the virus first identified in 2019. The benefit remains uncertain because neutralizing-antibody levels are not the same thing as clinical effectiveness, and future variants cannot be predicted. But regulators must make the choice before complete answers are available. Waiting for definitive efficacy data could mean deploying a vaccine after the targeted variant has already changed. ## COVID vaccination enters a new phase of strain management The decision also signals a transition in the federal vaccination strategy. Through the first year and a half of the U.S. campaign, the same original antigen served as the basis for primary doses and boosters even as Alpha, Delta and Omicron emerged. FDA is now formally acknowledging that the antigenic distance between circulating viruses and the original strain may justify changing the booster itself. That does not mean boosters will necessarily be updated on a fixed annual schedule, nor that BA.4 and BA.5 will remain dominant. FDA’s briefing materials emphasize the need for continued surveillance of variant proportions, vaccine effectiveness and laboratory immune responses. The agency is attempting to establish a framework that can be repeated as evidence changes. For the coming fall, however, the direction is set. The advisory committee has endorsed an Omicron-containing booster, FDA has selected BA.4 and BA.5 as the preferred variant component, and manufacturers have been told to begin building bivalent doses around that target. The country’s COVID-19 vaccination program is moving from repeated doses of an unchanged vaccine toward active management of vaccine strain composition.