Journal of autoimmunityDec 25, 2025

How long COVID-19 antibodies may affect fertility

Long Covid Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 27, 2026

Abstract

Essence

Antibodies against a SARS-CoV-2 Spike mimicry peptide impaired fertility-related outcomes in male mice.

Evidence

An in vivo mouse experiment injected peptide antibodies into healthy male mice and observed impaired fertility or delayed delivery time in fertile females.

Caveat

The result comes from antibody injection in mice and does not establish the frequency or magnitude of fertility effects in humans with long COVID-19.

Simplified

Molecular mimicry between foreign and self-antigens has long been recognized to initiate/exacerbate autoimmunity. Shared amino acid sequences have been found between SARS-CoV-2 Spike glycoprotein and human self-proteins, raising concerns about potential damages. We previously identified sequences with ≥5 identical residues shared by the SARS-CoV-2 Spike and spermatogenesis-associated proteins. One of these peptides was especially recognized by antibodies from infected, but not vaccinated individuals. Here, their pathogenic effects were explored in vivo. Injection of peptide antibodies into healthy male mice impaired fertility or delayed delivery time in fertile females, suggesting that cross-reactivity via molecular mimicry might affect the human reproductive system.

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