Please see this thread for more on COVID coding:
Anaphylaxis to COVID-19 vaccine is the only absolute contraindication for vaccination against COVID-19, and it is easy to code: T80.52XA, Anaphylactic reaction due to vaccination, initial encounter. An allergic reaction short of anaphylaxis would be coded with T50.B95A, for Adverse effect of other viral vaccines, initial encounter, and the manifestation, such as L50.0, Allergic urticaria (indexed “urticaria due to drugs”). [Article revision 3/10/21:
AHA/AHIMA FAQs rev. 3/1/21 recommends the manifestation of an allergic reaction to COVID-19 be coded with T78.49XA, Other allergy initial encounter]
It won’t surprise me if they make a dedicated COVID-19 vaccine code, but for now, the only viral vaccine that has its own code set is smallpox. If a patient were to seek medical attention for severe (even if expected) symptoms, like myalgias, headache, chills, or nausea, T50.B95A would be appropriate. Postvaccination fever is R50.83, and I would use it as a manifestation with T50.B95A. I believe adverse effects are a result of the medication (vaccine) properly administered but resulting in undesirable symptoms requiring action. Most of these side effects occur within 1-2 days of the injection.
The other code considered by the questioner’s team was T88.1XXA, Other complications following immunization, not elsewhere classified, initial encounter. In my opinion, there are several situations which warrant this code. Complications directly related to the procedure of immunization, but not related or due to the medication per se, might fit into this code. If a patient sought treatment because the injection was erroneously placed into their deltoid tendon or their shoulder joint, that would be T88.1XXA. A large hematoma or a firm lump from a resolving hematoma…T88.1XX- (7th character of “S” if it were a sequela). They are finding that patients develop localized rashes over the injection site, known as “COVID Arm,” or generalized rashes. These index to T88.1XX-.
EDITORS NOTE: This article has been updated to include a code that should be used for an allergic reaction to vaccines. Vaccination coding and billing
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T50.B95
Adverse effect of other viral vaccines
T50.Z95
Adverse effect of other vaccines and biological substances