Effectiveness of a Third Dose 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
Open accessAbstract
to January 5, 2022. Analyses were stratified by the period before and after the Omicron variant became the predominant strain (>50% of sequenced viruses) at each study site. During the period of Delta predominance across study sites in the United States (August-mid-December 2021), VE against laboratory-confirmed COVID-19-associated ED and UC encounters was 86% 14-179 days after dose 2, 76% ≥180 days after dose 2, and 94% ≥14 days after dose 3. Estimates of VE for the same intervals after vaccination during Omicron variant predominance were 52%, 38%, and 82%, respectively. During the period of Delta variant predominance, VE against laboratory-confirmed COVID-19-associated hospitalizations was 90% 14-179 days after dose 2, 81% ≥180 days after dose 2, and 94% ≥14 days after dose 3. During Omicron variant predominance, VE estimates for the same intervals after vaccination were 81%, 57%, and 90%, respectively. The highest estimates of VE against COVID-19-associated ED and UC encounters or hospitalizations during both Delta- and Omicron-predominant periods were among adults who received a third dose of mRNA vaccine. All unvaccinated persons should get vaccinated as soon as possible. All adults who have received mRNA vaccines during their primary COVID-19 vaccination series should receive a third dose when eligible, and eligible persons should stay up to date with COVID-19 vaccinations.
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Two doses of the ChulaCov19 vaccine may not be effective against the Omicron variant and a third dose is required.
“In terms of the Omicron variant, as reported in approved Covid-19 mRNA vaccines, two doses of the ChulaCov19 vaccine may not be effective and a third dose is required 5 .”
From Safety and immunogenicity of a prefusion non-stabilized spike protein mRNA COVID-19 vaccine: a phase I trial (2022) · cites this paper as [5]
The Discussion recommends a third mRNA vaccine dose during Omicron predominance because two-dose effectiveness was reduced. However, the study examined Moderna and Pfizer-BioNTech vaccines, not ChulaCov19, and it found that two doses still provided some protection against COVID-19–associated emergency or urgent care encounters and hospitalizations. It therefore does not establish that two ChulaCov19 doses may be ineffective or that a third ChulaCov19 dose is required. (LLM, conf=0.88)
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References 9 · Cited by 398
- Authors
- Thompson, M. G., Natarajan, K., Irving, S. A., Rowley, E. A., Griggs, E. P., Gaglani, M., Klein, N. P., Grannis, S. J., DeSilva, M. B., Stenehjem, E., Reese, S. E., Dickerson, M., Naleway, A. L., Han, J., Konatham, D., McEvoy, C., Rao, S., Dixon, B. E., Dascomb, K., Lewis, N., Levy, M. E., Patel, P., Liao, I.-C., Kharbanda, A. B., Barron, M. A., Fadel, W. F., Grisel, N., Goddard, K., Yang, D.-H., Wondimu, M. H., Murthy, K., Valvi, N. R., Arndorfer, J., Fireman, B., Dunne, M. M., Embi, P., Azziz-Baumgartner, E., Zerbo, O., Bozio, C. H., Reynolds, S., Ferdinands, J., Williams, J., Link-Gelles, R., Schrag, S. J., Verani, J. R., Ball, S., & Ong, T. C.
- Affiliations
- Regenstrief Institute (US)
- Corresponding author
- Thompson, Mark G.
- ORCID
- Thompson, Mark G.
- Natarajan, Karthik
- Irving, Stephanie A.
- Rowley, Elizabeth A.
- Griggs, Eric P.
- Gaglani, Manjusha
- Klein, Nicola P.
- Grannis, Shaun J.
- DeSilva, Malini B.
- Stenehjem, Edward
- Reese, Sarah E.
- Dickerson, Monica
- Naleway, Allison L.
- McEvoy, Charlene
- Rao, Suchitra
- Dixon, Brian E.
- Dascomb, Kristin
- Lewis, Ned
- Levy, Matthew E.
- Patel, Palak
- Liao, I-Chia
- Kharbanda, Anupam B.
- Barron, Michelle A.
- Fadel, William F.
- Goddard, Kristin
- Yang, Duck-Hye
- Wondimu, Mehiret H.
- Murthy, Kempapura
- Valvi, Nimish R.
- Fireman, Bruce
- Dunne, Margaret M.
- Zerbo, Ousseny
- Bozio, Catherine H.
- Reynolds, Sue
- Ferdinands, Jill
- Schrag, Stephanie J.
- Verani, Jennifer R.
- Ball, Sarah
- Ong, Toan C.
- Venue
- MMWR. Morbidity and Mortality Weekly Report
- Published
- 2022-01-21
- Volume
- 71
- Issue
- 4
- Pages
- 139-145
- ISSN
- 0149-2195 (ISSN-L)
- 1545-861X
- PMC
- PMC9351525
- OpenAlex
- W4206069935
- Cited by
- 398
- References
- 9
- Citations by year
- 2026: 9 · 2025: 15 · 2024: 36 · 2023: 119 · 2022: 218 · 2021: 1
- FWCI
- 47.42
- Type
- journal article
- Language
- en
- Open access
- diamond
- doi.org
- Locations
- MMWR Morbidity and Mortality Weekly Report (publishedVersion)
- PubMed Central (publishedVersion, public-domain)
- PubMed (publishedVersion)
- IUScholarWorks (Indiana University) (submittedVersion)
- Funders
- Intermountain Healthcare
- Pfizer
- GlaxoSmithKline
- Sanofi
- Kaiser Permanente
- Vanderbilt University
- BioFire Diagnostics
- Centers for Disease Control and Prevention
- School of Medicine, Indiana University
- Irving Medical Center, Columbia University
- Sanofi Pasteur
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Keywords
- COVID-19 pandemic, SARS-CoV-2, mRNA vaccines, third dose, vaccine effectiveness, emergency department visits, urgent care visits, hospitalization, Omicron variant, Delta variant, adults
- MeSH terms
- COVID-19, SARS-CoV-2, COVID-19 Vaccines, mRNA Vaccines, Vaccine Efficacy, Adult, Aged, Aged, 80 and over, Ambulatory Care, Emergency Service, Hospital, Female, Hospitalization, Humans, Immunization, Secondary, Male, Middle Aged, United States
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