The DOI matches its Crossref record; 1 of the 2 references it cites were found in a registry or an index, and 1 are not checked yet.
Vaccine effectiveness against SARS-CoV-2 infection with the Omicron or Delta variants following a two-dose or booster BNT162b2 or mRNA-1273 vaccination series: A Danish cohort study
Open accessAbstract
In this brief communication we are showing original research results with early estimates from Danish nationwide databases of vaccine effectiveness (VE) against the novel SARS-CoV-2 Omicron variant (B.1.1.529) up to five months after a primary vaccination series with the BNT162b2 or mRNA-1273 vaccines. Our study provides evidence of protection against infection with the Omicron variant after completion of a primary vaccination series with the BNT162b2 or mRNA-1273 vaccines; in particular, we found a VE against the Omicron variant of 55.2% (95% confidence interval (CI): 23.5 to 73.7%) and 36.7% (95% CI: -69.9 to 76.4%) for the BNT162b2 and mRNA-1273 vaccines, respectively, in the first month after primary vaccination. However, the VE is significantly lower than that against Delta infection and declines rapidly over just a few months. The VE is re-established upon revaccination with the BNT162b2 vaccine (54.6%, 95% CI: 30.4 to 70.4%).
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“As documented in the literature [19,22,26], VE during the Delta-dominant period was higher compared to the Omicron BA.1-dominant period”
From Vaccine effectiveness and duration of protection of COVID-19 mRNA vaccines against Delta and Omicron BA.1 symptomatic and severe COVID-19 outcomes in adults aged 50 years and over in France (2023) · cites this paper as [26]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“this decrease in protection was substantially higher against Omicron BA.1 compared to Delta [3,8,12,19,26].”
From Vaccine effectiveness and duration of protection of COVID-19 mRNA vaccines against Delta and Omicron BA.1 symptomatic and severe COVID-19 outcomes in adults aged 50 years and over in France (2023) · cites this paper as [26]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Several studies have described a drop over time of two-dose vaccine effectiveness against SARS-CoV-2 symptomatic infection;”
From Vaccine effectiveness and duration of protection of COVID-19 mRNA vaccines against Delta and Omicron BA.1 symptomatic and severe COVID-19 outcomes in adults aged 50 years and over in France (2023) · cites this paper as [26]
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“Still, numerous studies conducted during the Omicron BA.1 period have reported an increase in VE against infection caused by this variant following a booster dose [19,26,32-35].”
In the citing paper
“Notwithstanding these limitations, findings were consistent with those of other studies of vaccine effectiveness against omicron infection (BA.1 or BA.2 subvariants were not specified).27,32-36”
From Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections (2022) · cites this paper as [33]
In the citing paper
“Notwithstanding these limitations, consistent findings were reached, indicating rapid waning of vaccine protection against symptomatic Omicron infection that are consistent with findings of other studies for effectiveness against Omicron infection (with no BA.1/BA.2 subvariant specified)42–48.”
From Duration of mRNA vaccine protection against SARS-CoV-2 Omicron BA.1 and BA.2 subvariants in Qatar (2022) · cites this paper as [44]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
Espenhain, L., Funk, T., Overvad, M., Edslev, S. M., Fonager, J., Ingham, A. C., Rasmussen, M., Madsen, S. L., Espersen, C. H., Sieber, R. N., et al. (2021) · Eurosurveillance · doi:10.2807/1560-7917.es.2021.26.50.2101146 · Cited by 189
Self-citationAnalysis of licensed over-the-counter (OTC) antibiotics in the European Union and Norway, 2012
Both, L., Botgros, R., & Cavaleri, M. (2015) · Eurosurveillance · doi:10.2807/1560-7917.es.2015.20.34.30002 · Cited by 18
Research works printed but not linked: 1
- Andrews N , Stowe J , Kirsebom F , et al. Effectiveness of COVID-19 vaccines against the Omicron (B.1.1.529) variant of concern [Preprint]. https://khub.net/documents/135939561/430986542/Effectiveness+of+COVID-19+vaccines+against+Omicron+variant+of+concern.pdf/f423c9f4-91cb-0274-c8c5-70e8fad50074
Cited by
Sorted by citations
T cell responses to SARS-CoV-2 spike cross-recognize Omicron
Keeton, R., Tincho, M. B., Ngomti, A., Baguma, R., Benede, N., Suzuki, A., Khan, K., Cele, S., Bernstein, M. P., Karim, F., et al. (2022) · Nature · doi:10.1038/s41586-022-04460-3 · Cited by 617
Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections
Altarawneh, H. N., Chemaitelly, H., Ayoub, H. H., Tang, P., Hasan, M. R., Yassine, H. M., Al-Khatib, H. A., Smatti, M. K., Coyle, P., Al-Kanaani, Z., et al. (2022) · New England Journal of Medicine · doi:10.1056/nejmoa2203965 · Cited by 551
Effectiveness of mRNA-1273 against SARS-CoV-2 omicron and delta variants
Tseng, H. F., Ackerson, B. K., Luo, Y., Sy, L. S., Talarico, C. A., Tian, Y., Bruxvoort, K. J., Tubert, J. E., Florea, A., Ku, J. H., et al. (2022) · doi:10.1101/2022.01.07.22268919 · Cited by 541
Effect of mRNA Vaccine Boosters against SARS-CoV-2 Omicron Infection in Qatar
Abu-Raddad, L. J., Chemaitelly, H., Ayoub, H. H., AlMukdad, S., Yassine, H. M., Al-Khatib, H. A., Smatti, M. K., Tang, P., Hasan, M. R., Coyle, P., et al. (2022) · New England Journal of Medicine · doi:10.1056/nejmoa2200797 · Cited by 380
Buchan, S. A., Chung, H., Brown, K. A., Austin, P. C., Fell, D. B., Gubbay, J. B., Nasreen, S., Schwartz, K. L., Sundaram, M. E., Tadrous, M., et al. (2022) · JAMA Network Open · doi:10.1001/jamanetworkopen.2022.32760 · Cited by 356
Metadata
- Authors
- Hansen, C. H., Schelde, A. B., Moustsen-Helm, I. R., Emborg, H.-D., Krause, T. G., Mølbak, K., & Valentiner-Branth, P.
- Affiliations
- Statens Serum Institut (DK)
- ORCID
- Venue
- medRxiv
- Publisher
- openRxiv
- Published
- 2021-12-21
- OpenAlex
- W4200175757
- Cited by
- 133
- References
- 1
- Citations by year
- 2026: 2 · 2025: 1 · 2024: 8 · 2023: 25 · 2022: 97
- Type
- posted content
- Language
- en
- Open access
- green
- doi.org
- Locations
- medRxiv (acceptedVersion)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Social Sciences › Health › Vaccine Coverage and Hesitancy
- Keywords
- vaccine effectiveness, SARS-CoV-2, Omicron variant, Delta variant, BNT162b2, mRNA-1273, COVID-19 vaccines, booster vaccination, waning immunity, Danish cohort
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
