Allergy to arthropod bite; Feeling sick; Mosquito bite; mosquito bites that caused her arm to be swollen; mosquito bites that caused her arm to be red; Arm  like it was on fire; Peripheral lymphadenopathy; Nausea; mosquito bite; White blood cell abnormalities; This spontaneous case was reported by a consumer and describes the occurrence of ALLERGY TO ARTHROPOD BITE (Allergy to arthropod bite) in a 74-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product VENETOCLAX (VENCLEXTA) for Chronic lymphocytic leukemia.    Concomitant products included RITUXIMAB (RITUXAN) for Chronic lymphocytic leukaemia.   In January 2021, the patient started VENETOCLAX (VENCLEXTA) (Oral) 150 milligram. On 12-Feb-2021, VENETOCLAX (VENCLEXTA) (Oral) dosage was changed to 50 milligram. In May 2021, VENETOCLAX (VENCLEXTA) (Oral) dosage was changed to High dose 1 in 1 D. In 2021, VENETOCLAX (VENCLEXTA) (Oral) dosage was changed to 150 milligram. On 20-Jun-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. In July 2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In June 2021, the patient experienced LYMPHADENOPATHY (Peripheral lymphadenopathy). In 2021, the patient experienced ALLERGY TO ARTHROPOD BITE (Allergy to arthropod bite) (seriousness criterion hospitalization), WHITE BLOOD CELL DISORDER (White blood cell abnormalities), NAUSEA (Nausea) and ARTHROPOD BITE (mosquito bite). In September 2021, the patient experienced ARTHROPOD BITE (Mosquito bite), PERIPHERAL SWELLING (mosquito bites that caused her arm to be swollen), ERYTHEMA (mosquito bites that caused her arm to be red) and SKIN BURNING SENSATION (Arm  like it was on fire). On 16-Sep-2021, the patient experienced MALAISE (Feeling sick). At the time of the report, ALLERGY TO ARTHROPOD BITE (Allergy to arthropod bite), MALAISE (Feeling sick) and NAUSEA (Nausea) outcome was unknown, ARTHROPOD BITE (Mosquito bite), PERIPHERAL SWELLING (mosquito bites that caused her arm to be swollen), ERYTHEMA (mosquito bites that caused her arm to be red) and SKIN BURNING SENSATION (Arm  like it was on fire) had not resolved and WHITE BLOOD CELL DISORDER (White blood cell abnormalities), LYMPHADENOPATHY (Peripheral lymphadenopathy) and ARTHROPOD BITE (mosquito bite) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In May 2021, Blood test: white count went down.         This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in.  Company comment: This is a spontaneous case reported by a consumer. A 74-year-old female patient, treated with Venetoclax for chronic lymphocytic leukemia, received 2 doses of mRNA-1273 vaccine and was hospitalized for allergic reaction to mosquito bite. Onset date of the event was not provided; hence, latency cannot be assessed. After first dose, patient experienced swollen lymph node under left arm that was treated with steroids. Then she got several mosquito bites on that arm that had caused her arm to be swollen, red and it felt like it was on fire. Her physician was supposed to be calling in a prescription for steroids and an antibiotic. Patient had a previous episode of mosquito bite's swelling that resolved with steroids. Two months after first vaccination patient felt a little sick, but no further details regarding clinical course, diagnostic tests or treatment performed were disclosed. Non serious events of white blood cell disorder and nausea were also reported. Exaggerated reaction to insect bites may be seen in lymphoproliferative disorders, especially chronic lymphocytic leukemia. Regarding Venetoclax, reported as co-suspect drug, it could be a contributory factor for white blood cell disorder and nausea. Patient stated that Venetoclax caused her white count went down and it made sick to her stomach. The physician switched her to another prescription because Venclexta was "killing her white blood cells" and Venclexta was not working. Concomitant product RITUXIMAB could also be a contributory factor for nausea and white blood cell disorder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 01-Oct-2021: Significant follow up appended On 01-Nov-2021: Significant follow-up received includes event information, narrative description updated.; Sender's Comments: This is a spontaneous case reported by a consumer. A 74-year-old female patient, treated with Venetoclax for chronic lymphocytic leukemia, received 2 doses of mRNA-1273 vaccine and was hospitalized for allergic reaction to mosquito bite. Onset date of the event was not provided; hence, latency cannot be assessed. After first dose, patient experienced swollen lymph node under left arm that was treated with steroids. Then she got several mosquito bites on that arm that had caused her arm to be swollen, red and it felt like it was on fire. Her physician was supposed to be calling in a prescription for steroids and an antibiotic. Patient had a previous episode of mosquito bite's swelling that resolved with steroids. Two months after first vaccination patient felt a little sick, but no further details regarding clinical course, diagnostic tests or treatment performed were disclosed. Non serious events of white blood cell disorder and nausea were also reported. Exaggerated reaction to insect bites may be seen in lymphoproliferative disorders, especially chronic lymphocytic leukemia. Regarding Venetoclax, reported as co-suspect drug, it could be a contributory factor for white blood cell disorder and nausea. Patient stated that Venetoclax caused her white count went down and it made sick to her stomach. The physician switched her to another prescription because venclexta was "killing her white blood cells" and Venclexta was not working. Concomitant product RITUXIMAB could also be a contributory factor for nausea. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.