Effectiveness and durability of a fourth dose of ancestral-strain mRNA vaccines against SARS-CoV-2 infection: a nationwide matched cohort study in Qatar
Bibliographic record
Abstract
Concerns about waning immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the emergence of new variants underscore the need for booster doses. Using a matched cohort design, this study evaluated the relative effectiveness and durability of a fourth dose of ancestral-strain mRNA vaccines (BNT162b2 or mRNA-1273) in preventing SARS-CoV-2 infection, compared to three doses, between February 10, 2021 and May 13, 2024 in Qatar. The fourth dose conferred modest additional protection against infection, with an adjusted hazard ratio for infection of 0.91 (95% CI: 0.81-1.02), corresponding to a relative vaccine effectiveness of 9.2% (95% CI: - 1.7 to 18.9%). Protection peaked within the first three months of vaccination at 35.0% (95% CI: 20.6-46.8%) but waned rapidly thereafter, becoming negligible beyond that period. These findings highlight the modest and short-term protection of ancestral-strain vaccines against omicron subvariants and support the need for next-generation vaccines offering more durable immunity.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".