FDA Calls for Fall COVID Boosters , To Target Omicron Subvariants.br NBC News reports that on June 30, br the Food and Drug Administration asked vaccine makers to modify upcoming booster shots to target subvariants of Omicron.br The Omicron subvariants the agency wishes to target are BA.4 and BA.5.br Officials have called on vaccine makers Pfizer-BioNTech and Moderna to produce bivalent vaccines, .br which are intended to target the original strain of COVID-19 as well as its subvariants.br As we move into the fall br and winter, it is critical that br we have safe and effective vaccine boosters that can br provide protection... , Dr. Peter Marks, FDA, via NBC News.br ... against circulating br and emerging variants to prevent the most severe consequences of COVID-19. , Dr. Peter Marks, FDA, via NBC News.br As of the week ending June 25, Omicron subvariants BA.4 and BA.5 were responsible for 52 of all new cases of COVID-19.br Per the Centers for Disease Control and Prevention, BA.1, the first variant of br Omicron, caused 0 of new cases.br Pfizer and Moderna have thus far br altered vaccines to target the br original strain of COVID-19 and BA.1.br which increased the immune response to earlier iterations, though both have waned in their efficacy against BA.4 and BA.