CPT® Code 90658

A trivalent, split virus influenza vaccine (IIV3) is designed for intramuscular administration and is specifically formulated to provide active, long-term immunity against influenza. Unlike immune globulins, which offer short-term, passive immunity, this vaccine works by stimulating the recipient's immune system to recognize and combat the influenza virus. The vaccine contains altered versions of the virus, prompting the immune system to produce its own antibodies. This process enables the body to "remember" how to generate these antibodies upon future exposure to the actual virus, thereby enhancing the individual's ability to fight off influenza infections. The vaccine is produced using embryonated chicken eggs, where the influenza virus is cultivated, harvested, and inactivated with formaldehyde. The virus is then concentrated, purified, and chemically disrupted to create a split virus, which is further purified to ensure safety and efficacy. The trivalent formulation includes two distinct strains of influenza type A and one strain of influenza type B, providing broad protection against circulating influenza viruses. For billing purposes, the CPT® code 90658 is used to report the 0.5 mL dosage of this vaccine, while a separate code, 90657, is designated for a 0.25 mL dosage. It is important to note that these codes solely represent the vaccine product administered, and the intramuscular injection itself should be reported separately.