Can the SARS-CoV-2 spike protein persist in the body after infection or vaccination, and for how long?
Executive summary
Multiple peer-reviewed studies and recent reviews report that SARS‑CoV‑2 spike protein or spike fragments can be detected weeks to many months after acute infection in some people, and a handful of recent studies and news reports document detectable spike in a subset of post‑vaccine or post‑infection patients for many months — including reports up to 15 months after infection (S1 in monocytes) [1] and up to ~709–700+ days after vaccination in selected participants with post‑vaccination syndrome [2] [3]. Reviews link viral‑component persistence, including spike or S1 fragments, to proposed mechanisms for long COVID and related syndromes but note uncertainty about how common and how causally important this persistence is [4].
1. Evidence that spike protein can persist long after acute infection
Several laboratory studies and reviews document detection of spike protein or spike subunits long after symptom resolution; for example, a report of S1 in CD16+ monocytes up to 15 months post‑infection was cited in a 2025 Frontiers review [1]. A broader review of spike’s pathophysiological roles frames “viral component persistence” — including S and S1 — as one of the main mechanisms hypothesized to drive long COVID symptoms [4]. These items show biochemical detection of spike components in specific cell types or biofluids in selected cohorts, not universal persistence across all recovered patients [1] [4].
2. Reports of spike detection after vaccination — limited subgroup findings
News coverage of a Yale‑linked study says that while spike is typically detectable for only days after vaccination, “some participants with PVS had detectable levels more than 700 days after their last vaccination,” and that persistent spike has been associated with long COVID in some studies [2]. Independent summaries and fact‑checks restate that finding, emphasizing it occurred in a subset of people with post‑vaccination syndrome and is not established as a general population phenomenon [3]. Available sources do not provide population‑level prevalence or proof that vaccine‑derived spike routinely persists that long in most vaccinated people [2] [3].
3. What “persistence” means biologically and methodologically
Reviews stress that “persistence” can mean intact spike protein, subunits (for example S1), or spike carried on extracellular vesicles/exosomes — and detection methods vary (protein assays, mass spectrometry, cell staining) [4] [5]. One early report found spike on exosomes for at least four months after vaccination, but that was a small, focused finding and has been discussed in activist as well as academic outlets [5]. The detection of spike fragments in particular cell types (e.g., CD16+ monocytes) does not necessarily imply abundant circulating intact spike or ongoing viral replication [1] [4].
4. Clinical significance — observed association, unresolved causation
Authors and reviewers connect persistent spike detection to immune activation pathways hypothesized in long COVID — cytokine production, immune dysregulation, endothelial and thromboinflammatory effects — but they also state that mechanisms remain unclear and causality is not established [4]. Yale researchers and others are explicitly investigating whether removing persistent spike (for example with monoclonal antibodies) would alter symptoms, which reflects a working hypothesis rather than proven therapy [2].
5. Competing interpretations and limits of current reporting
Sources present competing emphases: some papers and reviews treat spike persistence as a plausible pathogenic contributor to post‑acute syndromes [1] [4], while news and fact‑check summaries underline that long persistence reports come from selected cohorts (e.g., PVS or PASC patients) and cannot be extrapolated to all vaccinated or infected people without broader, controlled studies [2] [3]. Large, representative prevalence data are not provided in these sources; available sources do not mention population‑level rates of long spike persistence.
6. Bottom line for readers and researchers
Laboratory and clinical teams have documented spike or spike fragment detection months to more than a year after infection and, in narrowly defined cohorts, after vaccination (up to ~15 months post‑infection in one report and up to ~709–700+ days in selected PVS participants) [1] [2] [3]. These findings are important leads but not proof that persistent spike is common, or that it is the primary driver of long COVID or post‑vaccine syndromes; larger, controlled studies with standardized assays are required to determine prevalence, source (viral vs. vaccine), and causal impact [4] [2].