Nikhil Prasad Fact checked by:Thailand Medical News Team May 09, 2025 6 hours, 27 minutes ago
Medical News: Natural Blood Antibodies May Shield Some People from Severe COVID-19
Researchers from the International Centre for Diarrhoeal Disease Research in Bangladesh, Nantes Université and CHU de Nantes in France have uncovered new insights into how natural antibodies linked to blood groups may play a critical role in protecting people from symptomatic COVID-19. Their findings come from a detailed study conducted on 99 COVID-19 patients in Dhaka, Bangladesh, and 59 healthy controls, both during and before the pandemic.
How Blood Group Antibodies Could Naturally Protect Against Severe COVID-19
The research explored whether naturally occurring anti-carbohydrate antibodies—specifically those targeting blood group antigens A and B—could provide some level of innate immune defense. This
Medical News report dives into how these antibodies may reduce the chances of experiencing COVID-19 symptoms, especially among people with blood type O.
A Closer Look at the Study Design
The scientists collected blood and saliva samples from patients and healthy individuals and measured levels of natural anti-A, anti-B, anti-Tn-Mono, and anti-αGal antibodies. Participants were classified based on blood group, secretor status (a genetic trait affecting antigen presence in secretions), and Lewis blood group antigens. The antibody levels were then tracked over three months post-infection.
Researchers used enzyme-linked immunosorbent assays (ELISA) to detect antibody titers. The study population was diverse in age, gender, and COVID-19 symptom severity. Patients were grouped as asymptomatic or symptomatic (mild to severe).
Key Findings Highlight Natural Protection
The most striking finding was that symptomatic COVID-19 patients had significantly lower levels of natural anti-A and anti-B IgG antibodies compared to healthy individuals and asymptomatic patients. These differences were particularly noticeable among people under 45 years old and in females.
Importantly, individuals with higher levels of anti-A and anti-B antibodies were more likely to have asymptomatic infections, suggesting these natural antibodies may reduce disease severity. Antibody levels among asymptomatic patients remained relatively high for up to three months post-infection, while symptomatic individuals showed sharper declines.
Gender also played a role. Female participants—both healthy and infected—showed higher levels of protective antibodies than their male counterparts, which may partly explain why women tend to experience less severe COVID-19 outcomes.
Blood Group and Genetic Traits Also Influence Protection
The study also analyzed whether a person’s secretor status and Lewis antigen profile impacted immunity. Secretors and Lewis-positive individuals had varying levels of antibodies, but no strong association was found between these traits and COVID-19 symptom severity. However, healthy secretors h
ad significantly higher anti-A antibody levels than infected secretors, hinting at a possible protective effect.
In terms of blood groups, type O individuals—who naturally have both anti-A and anti-B antibodies—appeared better protected, aligning with previous studies linking blood type O with reduced COVID-19 severity.
Why This Research Matters
This research opens the door to understanding how natural antibodies could serve as an early defense against SARS-CoV-2. It suggests that the presence or absence of specific antibodies—not just the blood group—can influence how our bodies respond to the virus. While no major differences were found in infection rates across blood types, antibody levels seemed to strongly affect disease outcomes.
The findings support the theory that natural immunity via anti-carbohydrate antibodies, especially anti-A and anti-B, may prevent the virus from attaching to and entering cells through its ACE2 receptor—a key step in the infection process.
Conclusion
In summary, people with naturally higher levels of anti-A and anti-B antibodies—most commonly those with blood type O and especially women—may be less likely to develop symptomatic COVID-19. This research also highlights how gender, age, and genetic traits may influence natural immunity. While the results are promising, larger studies are needed to fully understand how these natural antibodies can be leveraged in public health strategies or potential therapies.
Ultimately, this study strengthens the case that our own biology could hold hidden layers of protection against future waves of COVID-19.
The study findings were published in the peer reviewed journal: Frontiers in Medicine.
https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2025.1554785/full
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Read Also:
https://www.thailandmedical.news/news/covid-19-news-uk-study-shows-that-individuals-with-blood-type-o-are-at-higher-risk-of-strokes-after-oxford-astrazeneca-covid-19-vaccine
https://www.thailandmedical.news/news/danish-study-validates-that-those-with-blood-group-o-and-those-with-pre-existing-anti-a-and-anti-b-antibodies-have-a-lower-risk-of-covid-19
https://www.thailandmedical.news/news/covid-19-research-harvard-study-shows-that-covid-19-patients-with-blood-groups-a-and-ab-at-higher-risks-of-major-adverse-cardiovascular-events
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/pages/thailand_doctors_listings
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