Effectiveness of Monovalent mRNA COVID-19 Vaccination in Preventing COVID-19–Associated Invasive Mechanical Ventilation and Death Among Immunocompetent Adults During the Omicron Variant Period — IVY Network, 19 U.S. States, February 1, 2022–January 31, 2023

Group Case-patients who received IMV or died, no. of monovalentvaccinated /total no. (%) Control patients, no. of monovalent-vaccinated / total no. (%) Median interval from last monovalent mRNA vaccine dose to illness onset (IQR), days Adjusted VE against IMV and death % (95% CI) Overall 216/362 (60) 3,080/4,059 (76) 248 (138-378) 62 (52-70) Age group, yrs 18-64 85/163 (52) 1,421/2,095 (68) 263 (144-380) 57 (39-70) 65 131/199 (66) 1,659/1,964 (84) 238 (133-375) 69 (57-78) Interval from last monovalent mRNA vaccine dose to illness onset, days 7-179 63/209 (30) 1,112/2,091 (53) 109 (68-145) 76 (66-83) 180-364 95/241 (39) 1,110/2,089 (53) 269 (220-317) 54 (37-66) 365 58/204 (28) 858/1,837 (47) 455 (402-549) 56 (36-69) Interval from last monovalent mRNA vaccine dose to illness onset, by no. of doses received 7 days before illness onset 2 doses 87/233 (37) 1,061/2,040 (52) 395 (292-512) 53 (37-65) 3 doses 108/254 (43) 1,534/2,513 (61) 210 (129-313) 65 (54-74) 4 doses 19/95 (20) 461/968 (48) 118 (66-169) 83 (70-91) 7-179 days before illness onset 2 doses 6/152 (4) 108/1,087 (10) 114 (72-153) -** 3 doses 42/188 (22) 633/1,612 (39) 116 (75-147) 70 (55-81) 4 doses 15/91 (16) 353/860 (41) 94 (55-135) 84 (69-92) 180 days before illness onset 2 doses 81/227 (36) 953/1,932 (49) 418 (326-531) 50 (32-64) 3 doses 66/212 (31) 901/1,880 (48) 292 (235-366) 59 (42-72) 4 doses 4/80 (5) 108/615 (18) 223 (197-258) -** Abbreviations: IMV = invasive mechanical ventilation; VE = vaccine effectiveness. * https://www.cdc.gov/flu/vaccines-