Nikhil Prasad Fact checked by:Thailand Medical News Team Aug 09, 2026 49 minutes ago
Scientists investigating why COVID-19 antibodies remain detectable longer in some people than others have found that a naturally occurring hormone may provide an important part of the answer. New research suggests that levels of 17β-estradiol, a form of estrogen found in both women and men, are strongly associated with how long antibodies against SARS-CoV-2 persist after infection. Researchers Nicole Ivaska and Laura Rothschild are from the Department of Health Sciences, Ursinus College, Collegeville, Pennsylvania, USA. Their findings challenge the common practice of simply comparing immune responses between males and females.
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Higher natural estradiol levels were strongly associated with longer persistence of SARS-CoV-2 antibodies in young adults.
Researchers Look Beyond Biological Sex
The study involved 75 college students, 63 percent of whom were female, with most participants aged between 18 and 24. All had received a COVID-19 vaccine before the study and had detectable IgG antibodies against the SARS-CoV-2 nucleocapsid, or N protein, indicating previous natural infection.
Participants had their estradiol and testosterone concentrations measured using saliva samples. Researchers then examined how these hormone levels related to the number of weeks that anti-N antibodies remained detectable following infection.
Antibody persistence averaged approximately 15.4 weeks. Interestingly, women averaged 15.49 weeks while men averaged 15.29 weeks, showing virtually no meaningful difference based simply on biological sex.
Estradiol Emerges as the Strongest Predictor
The standout finding was the relationship between 17β-estradiol and antibody persistence. Estradiol showed a significant positive association with longer-lasting antibodies, with researchers reporting a correlation of 0.55.
When biological sex, testosterone and estradiol were analyzed together, adding hormone measurements substantially improved the researchers' ability to explain differences in antibody persistence. The model accounted for approximately 34 percent of the variation observed.
Estradiol emerged as the strongest positive predictor, with a standardized coefficient of 0.63 and a highly statistically significant result. Biological sex itself was not significant. Testosterone also failed to significantly predict antibody persistence in this main analysis.
Importantly, this
Medical News report highlights that estradiol should not be viewed simply as a "female hormone." Both males and females produce estradiol, and individual hormone concentrations can overlap.
Why Estradiol Could Affect Immunity
There are several biological reasons why estradiol might influence antibody durability. Estradiol is known to affect immune regulation, including B cells, which are responsible for producing antibodies.
The hormone has also been linked to stronger antibody production, antiviral immune responses and regulation of inflammation. It acts through estrogen rec
eptors that influence pathways controlling both innate immunity, the body's rapid first-line defenses, and adaptive immunity, which creates more specialized responses and immune memory.
Researchers therefore argue that measuring actual hormone concentrations may reveal biological differences that are missed when people are divided only into male and female groups.
Important Limitations Remain
The findings do not prove that raising estradiol will make COVID-19 antibodies last longer. This was a small, cross-sectional study conducted at one college, and hormone measurements were taken only once.
The researchers also relied on participants reporting when their previous infection occurred. Undocumented reinfections could therefore have affected the results. Furthermore, the antibody test detected whether anti-N IgG antibodies were present but did not measure their actual concentrations.
Conclusions
The findings suggest that individual hormone biology, particularly 17β-estradiol levels, may help explain why SARS-CoV-2 antibodies remain detectable longer in certain people. Rather than biological sex alone determining immune durability, the endocrine and immune systems appear to interact in a considerably more complex way. Larger longitudinal studies involving different ages and repeated hormone and antibody measurements will now be needed to establish whether estradiol directly influences long-term immune memory.
The study findings were published in the peer reviewed journal: Antibodies.
https://www.mdpi.com/2073-4468/15/4/72
Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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