Clinical outcomes among SARS-CoV-2 omicron-infected adults according to prior infection and vaccination history in Iran: A retrospective registry-based study
Vaccine·
- DOI
- 10.1016/j.vaccine.2026.128868
- PMID
- 42322678
- PMCID
- —
- OpenAlex
- W7165375573
- Study type
- Cohort study
- Publisher
- Elsevier BV
- Article type
- journal-article
- Integrity
- current
Why this research matters now
The findings provide context on observed hospitalization and mortality patterns among laboratory-confirmed Omicron cases according to documented prior immunity profiles in this Iranian registry population. The analysis does not estimate protection against acquiring infection.
Structured evidence summary
Research question
Among adults in Iran with laboratory-confirmed Omicron infection, the study assessed whether prior infection and vaccination history were associated with hospitalization and mortality.
Study design
This was a retrospective registry-based study of laboratory-confirmed cases. Associations were estimated using multivariable logistic regression adjusted for age, sex, comorbidities, and calendar period linked to predominant Omicron subvariant circulation.
Population and setting
The study included 4,674 adults with laboratory-confirmed COVID-19 in Hamedan Province, Iran, between March 2022 and March 2023. Participants were grouped by documented vaccination and prior infection status.
Main findings
Among infected adults, hybrid immunity was associated with lower observed hospitalization and mortality than vaccination alone. Prior infection alone was also associated with more favorable observed outcomes than vaccination alone, while adjustment attenuated but did not reverse the reported direction of the associations.
Public-health relevance
The findings provide context on observed hospitalization and mortality patterns among laboratory-confirmed Omicron cases according to documented prior immunity profiles in this Iranian registry population. The analysis does not estimate protection against acquiring infection.
Important limitations
Because the analysis was restricted to people with confirmed infection, it compares outcomes among cases rather than measuring prevention of infection. The retrospective registry-based design and the supplied abstract do not provide enough information for a fuller assessment of potential measurement, selection, or residual-confounding limitations; decision-grade interpretation requires the original paper.
GIDS interpretation
The article is discoverable as evidence concerning SARS-CoV-2 Omicron outcomes, vaccination, prior infection, and hybrid immunity in Iran. It supplies single-article context about outcomes among infected adults and should not be interpreted as confirmation of a live surveillance signal.
Related GIDS surveillance
Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.
Evidence relationships
This article has 10 auditable classifier relationships to diseases, places, topics, and study design.