Waning Effectiveness of mRNA Vaccines Against COVID-19

Waning 2-dose and 3-dose Effectiveness of mRNA Vaccines Against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults During Periods of Delta and Omicron Variant Predominance

VISION Network, 10 States, August 2021-January 2022

Jill M. Ferdinands, PhD; Suchitra Rao, MBBS; Brian E. Dixon, PhD; Patrick K. Mitchell, ScD; Malini B. DeSilva, MD; Stephanie A. Irving, MHS; Ned Lewis, MPH; Karthik Natarajan, PhD; Edward Stenehjem, MD; Shaun J. Grannis, MD; Jungmi Han; Charlene McEvoy, MD; Toan C. Ong, PhD; Allison L. Naleway, PhD; Sarah E. Reese, PhD; Peter J. Embi, MD; Kristin Dascomb, MD; Nicola P. Klein, MD; Eric P. Griggs, MPH; Deepika Konatham; Anupam B. Kharbanda, MD; Duck-Hye Yang, PhD; William F. Fadel, PhD; Nancy Grisel, MPP; Kristin Goddard, MPH; Palak Patel, MBBS; I-Chia Liao MPH; Rebecca Birch, MPH; Nimish R. Valvi, DrPH; Sue Reynolds, PhD; Julie Arndorfer, MPH; Ousseny Zerbo, PhD; Monica Dickerson; Kempapura Murthy, MBBS; Jeremiah Williams, MPH; Catherine H. Bozio, PhD; Lenee Blanton, MPH; Jennifer R. Verani, MD; Stephanie J. Schrag, DPhil; Alexandra F. Dalton, PhD; Mehiret H. Wondimu, MPH; Ruth Link-Gelles, PhD; Eduardo Azziz-Baumgartner, MD; Michelle A. Barron, MD; Manjusha Gaglani, MBBS; Mark G. Thompson, PhD; Bruce Fireman

Disclosures

Morbidity and Mortality Weekly Report. 2022;71(7):255-263. 

In This Article

Abstract and Introduction

Introduction

CDC recommends that all persons aged ≥12 years receive a booster dose of COVID-19 mRNA vaccine ≥5 months after completion of a primary mRNA vaccination series and that immunocompromised persons receive a third primary dose.* Waning of vaccine protection after 2 doses of mRNA vaccine has been observed during the period of the SARS-CoV-2 B.1.617.2 (Delta) variant predominance,[1–5] but little is known about durability of protection after 3 doses during periods of Delta or SARS-CoV-2 B.1.1.529 (Omicron) variant predominance. A test-negative case-control study design using data from eight VISION Network sites§ examined vaccine effectiveness (VE) against COVID-19 emergency department/urgent care (ED/UC) visits and hospitalizations among U.S. adults aged ≥18 years at various time points after receipt of a second or third vaccine dose during two periods: Delta variant predominance and Omicron variant predominance (i.e., periods when each variant accounted for ≥50% of sequenced isolates). Persons categorized as having received 3 doses included those who received a third dose in a primary series or a booster dose after a 2 dose primary series (including the reduced-dosage Moderna booster). The VISION Network analyzed 241,204 ED/UC encounters** and 93,408 hospitalizations across 10 states during August 26, 2021–January 22, 2022. VE after receipt of both 2 and 3 doses was lower during the Omicron-predominant than during the Delta-predominant period at all time points evaluated. During both periods, VE after receipt of a third dose was higher than that after a second dose; however, VE waned with increasing time since vaccination. During the Omicron period, VE against ED/UC visits was 87% during the first 2 months after a third dose and decreased to 66% among those vaccinated 4–5 months earlier; VE against hospitalizations was 91% during the first 2 months following a third dose and decreased to 78% ≥4 months after a third dose. For both Delta- and Omicron-predominant periods, VE was generally higher for protection against hospitalizations than against ED/UC visits. All eligible persons should remain up to date with recommended COVID-19 vaccinations to best protect against COVID-19–associated hospitalizations and ED/UC visits.

VISION Network methods have been previously published. [6] Eligible medical encounters were defined as those among adults aged ≥18 years with a COVID-19–like illness diagnosis†† who had received molecular testing (primarily reverse transcription–polymerase chain reaction assay) for SARS-CoV-2, the virus that causes COVID-19, during the 14 days before through 72 hours after the medical encounter

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*On November 29, 2021, CDC initially recommended a third dose of mRNA vaccine for all adults 6 months after receipt of the second primary series mRNA COVID-19 vaccine dose. The third dose of the BNT162b2 (Pfizer-BioNTech) vaccine was the same dosage as the primary series; however, the third dose of the mRNA-1273 (Moderna) vaccine was a reduced dosage compared with the primary series for all but immunocompromised persons; the third dose was either a 100-μg or 50-μg dose of Moderna vaccine or a 30-μg dose of the Pfizer-BioNTech vaccine. On January 4, 2022, CDC amended the interval to 5 months after receipt of the second dose for recipients of the Pfizer-BioNTech vaccine. On January 7, 2022, CDC amended the interval to 5 months for recipients of the Moderna vaccine. CDC recommends the Pfizer-BioNTech booster at 5 months, and an additional primary dose for certain immunocompromised children (https://www.cdc.gov/media/releases/2022/s0104-Pfizer-Booster.html). CDC recommends the Moderna booster at 5 months after completion of the primary series. (https://www.cdc.gov/media/releases/2022/s0107-moderna-booster.html). CDC recommends additional primary doses for some immunocompromised persons (https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html).
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3961378
§Funded by CDC, the VISION Network includes Baylor Scott & White Health (Texas), Columbia University Irving Medical Center (New York), HealthPartners (Minnesota and Wisconsin), Intermountain Healthcare (Utah), Kaiser Permanente Northern California (California), Kaiser Permanente Northwest (Oregon and Washington), Regenstrief Institute (Indiana), and University of Colorado (Colorado).
Partners contributing data on medical events (and estimated dates of Omicron predominance) were as follows: California (December 21), Colorado (December 19), Indiana (December 26), Minnesota and Wisconsin (December 25), New York (December 18), Oregon (December 24), Texas (December 16), Utah (December 24), and Washington (December 24). The study period began in September 2021 for partners located in Texas.
**ED data at Columbia University Irving Medical Center and HealthPartners exclude encounters that were transferred to an inpatient setting.
††COVID-19–like illness diagnoses included acute respiratory illness (e.g., COVID-19, respiratory failure, or pneumonia) or related signs or symptoms (cough, fever, dyspnea, vomiting, or diarrhea) using diagnosis codes from the International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision.
§§ https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-additional-vaccine-dose-certain-immunocompromised
¶¶VE was calculated as [1 − odds ratio] x 100%, estimated using a test-negative design, which can be considered a case-control design in which case-patients were those whose outcome was confirmed COVID-19 and control patients were those with COVID-19–like illness and negative SARS-CoV-2 test results. All VE models were conditioned on calendar week and geographic area and adjusted for age, local virus circulation (percentage of SARS-CoV-2–positive results from testing within the counties surrounding the facility on the date of the encounter), propensity to be vaccinated (calculated separately for each VE estimate), and other patient and facility characteristics. Generalized boostered regression tree methods were used to estimate the propensity to be vaccinated based on sociodemographic characteristics, underlying medical conditions, and facility characteristics.
***Immunocompromising conditions were derived from lists used in previous studies of large hospital-based or administrative databases and included the following conditions: 1) solid malignancies, 2) hematologic malignancies, 3) rheumatologic or inflammatory disorders, 4) other intrinsic immune conditions or immunodeficiencies, and 5) organ or stem cell transplants. https://www.cdc.gov/mmwr/volumes/70/wr/mm7044e3.htm?s_cid=mm7044e3_w
†††The index date for each medical visit was defined as either the date of collection of a respiratory specimen associated with the most recent positive or negative SARS-CoV-2 test result before the medical visit or the date of the medical visit (if testing occurred only after the admission or visit date).
§§§45 C.F.R. part 46; 21 C.F.R. part 56.

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