This literature-non-study case was reported in a literature article and describes the occurrence of COVID-19 (SARS-COV-2 Delta variant infection) in a patient of an unknown age and gender who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. LITERATURE REFERENCE: Differential evasion of Delta and Omicron immunity and enhanced fusogenicity of SARS-CoV-2 Omicron BA.4/5 and BA.2.12.1 subvariants. No Medical History information was reported. On an unknown date, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form and second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced COVID-19 (SARS-COV-2 Delta variant infection) (seriousness criterion hospitalization). At the time of the report, COVID-19 (SARS-COV-2 Delta variant infection) outcome was unknown. Related. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: (Positive) Positive. For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered COVID-19 (SARS-COV-2 Delta variant infection) to be related. Treatment and concomitant medications were not reported. Patient received three doses of the Moderna mRNA-1273 vaccine. Patient had COVID-19 infection with Delta variant and was admitted to ICU. Plasma samples were collected 3 days after ICU admission. Delta variant of SARS CoV-2 infection was confirmed by viral RNA extraction on nasal swabs with QIAamp. MinElute Virus Spin kit followed by RT-PCR and Sanger sequencing. The nAb titer of Delta patient sera was among the highest, with even 66.5% higher than D614G. An increase in nAb titer of BA.4/5 and BA.2.12.1, with NT50 5.0-fold (p <0.01) and 5.5-fold (p <0.001) lower than D614G, respectively was observed. Omicron subvariants containing mutations at 452 are more effectively 238 neutralized by Delta-wave ICU patients. Company comment: This literature-non-study case concerns a patient, of unknown age and unknown gender, with no medical history reported, who experienced the unexpected, serious (hospitalization) AESI of COVID-19 (SARS-CoV-2 Delta variant infection). The event occurred unknown number of days after receiving the third dose of the mRNA-1273 vaccine. Of note, the vaccination date and the event onset date were not provided; hence, the onset latency could not be determined. No symptoms were reported. It was reported that plasma samples were collected 3 days after Intensive Care Unit (ICU) admission. The variant of SARS-CoV-2 infecting the ICU patients was confirmed by viral RNA extraction on nasal swabs with QIAamp MinElute Virus Spin kit followed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Sanger sequencing to identify the variant. The neutralizing antibody (nAb) titer of the Delta patient sera for the Delta variant was among the highest, with even 66.5% higher than D614G. Noticeably, BA.4/5 and BA.2.12.1 exhibited less escape of neutralization by Delta-wave sera as evidenced by fewer NT50 values that fell below the limit of detection. Not surprisingly, the new Omicron subvariants containing mutations at 452 are more effectively neutralized by Delta-wave ICU patients. The results showed that Delta-wave patient sera neutralized more efficiently against not only Delta but also Omicron BA.4/5 and BA.2.12.1 subvariants. According to the authors, the findings emphasize the importance of booster vaccination in control of the continually evolving Omicron variants. No further clinical information (including details about hospitalization and clinical course) was available for medical review. Treatment information was also not provided. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. This case was linked to MOD-2022-609055 (E2B Linked Report). Sender's Comments: This literature-non-study case concerns a patient, of unknown age and unknown gender, with no medical history reported, who experienced the unexpected, serious (hospitalization) AESI of COVID-19 (SARS-CoV-2 Delta variant infection). The event occurred unknown number of days after receiving the third dose of the mRNA-1273 vaccine. Of note, the vaccination date and the event onset date were not provided; hence, the onset latency could not be determined. No symptoms were reported. It was reported that plasma samples were collected 3 days after Intensive Care Unit (ICU) admission. The variant of SARS-CoV-2 infecting the ICU patients was confirmed by viral RNA extraction on nasal swabs with QIAamp MinElute Virus Spin kit followed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Sanger sequencing to identify the variant. The neutralizing antibody (nAb) titer of the Delta patient sera for the Delta variant was among the highest, with even 66.5% higher than D614G. Noticeably, BA.4/5 and BA.2.12.1 exhibited less escape of neutralization by Delta-wave sera as evidenced by fewer NT50 values that fell below the limit of detection. Not surprisingly, the new Omicron subvariants containing mutations at 452 are more effectively neutralized by Delta-wave ICU patients. The results showed that Delta-wave patient sera neutralized more efficiently against not only Delta but also Omicron BA.4/5 and BA.2.12.1 subvariants. According to the authors, the findings emphasize the importance of booster vaccination in control of the continually evolving Omicron variants. No further clinical information (including details about hospitalization and clinical course) was available for medical review. Treatment information was also not provided. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.