Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on Genetics & Immune Health. Browse all Genetics & Immune Health education

Almost everyone has had strep throat at some point, but a smaller group of people seems to catch it over and over — several times a year, season after season. Recurrent strep is not simply a matter of exposure or hygiene. Your immune system's genetically shaped ability to recognize and clear Streptococcus pyogenes plays a real role in who gets sick repeatedly and who shrugs it off. Understanding those genetic factors can explain a pattern that often feels random and frustrating.

Why some people are strep-prone

Strep infection depends on a race between the bacteria and your immune response. When the immune system quickly recognizes streptococcal antigens and mounts a strong, specific antibody response, the infection is cleared and future exposures are handled faster. When that recognition is slower or weaker, the same bacteria can gain a foothold again and again. Environmental factors — close contact in schools and households, smoking exposure, and stress — matter, but they interact with an immune system whose baseline capacity is partly inherited.

HLA genes and antibody recognition

The strongest genetic signal in recurrent strep involves the human leukocyte antigen system, especially HLA-DQB1 and HLA-DRB1. These genes control how immune cells present bacterial fragments to the rest of the immune system. Research on children with recurrent tonsillitis has found that certain HLA types are associated with weaker antibody responses to key streptococcal toxins, meaning those individuals generate less protective immunity after each infection. In effect, their immune systems have a harder time "learning" from strep, so protection does not accumulate the way it does in others.

Innate immunity and MBL2

Before antibodies even develop, the innate immune system provides a first line of defense. The MBL2 gene encodes mannose-binding lectin, a protein that tags bacteria for destruction through the complement system. Common MBL2 variants substantially lower circulating levels of this protein, and MBL deficiency is one of the more frequent immune variations in the general population. People with low mannose-binding lectin can be more prone to recurrent bacterial infections, including of the upper respiratory tract, because that early tagging step is less efficient.

Inflammation, immune signaling, and susceptibility

Genes that regulate inflammatory signaling also shape how the body responds to infection. Variants affecting cytokine production can tilt an immune response toward being either too sluggish to clear bacteria efficiently or so intense that it drives symptoms without faster clearance. This genetic tuning helps explain why two people exposed to the same strep-positive household member can have very different experiences — one clears it silently while the other develops a full infection and needs care.

What genetic insight can and cannot do

A genetic test does not diagnose strep — that requires a rapid antigen test or throat culture from a provider — and it cannot treat an infection. What it can do is offer pathway-level context about your immune signaling and defense biology. The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights spanning immune and inflammatory pathways. That context is a starting point for a conversation with a qualified provider about recurrent infections, not a verdict or a treatment plan. Genetics is a guide, not a guarantee.

Frequently Asked Questions

Is susceptibility to strep inherited?

Partly. Genes in the HLA system, such as HLA-DQB1 and HLA-DRB1, influence how well your immune system recognizes streptococcal antigens, and MBL2 affects innate bacterial clearance. These inherited factors combine with exposure, hygiene, and overall health to shape how often someone develops strep infections.

Can a genetic test tell me if I will get strep?

No. A genetic test does not diagnose, predict, or prevent strep infections. It offers pathway-level context about immune and inflammatory biology. Only a provider using a rapid antigen test or throat culture can diagnose an active infection and recommend appropriate treatment.

Why do children get recurrent strep more than adults?

Children have more close contact in schools and daycares and immune systems still building their antibody memory. Certain HLA types are linked to weaker antibody responses to streptococcal toxins, which can make some children less able to develop lasting protection, leading to repeated infections during those years.

Does a weak immune response mean something is wrong?

Not necessarily. Common variants like those in MBL2 are frequent in healthy people and simply represent normal human variation. They can raise susceptibility to some infections without indicating a serious immune disorder. Persistent or severe recurrent infections should always be evaluated by a qualified healthcare provider.

Know your biology before you act on it. The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights so you can bring a clearer picture of your genetic landscape to a conversation with a qualified provider. Genetics is a guide, not a guarantee — test before you invest in any protocol.

This article is part of the PlexusDx Education Hub. Browse all Genetics & Immune Health education

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not diagnose any condition and does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol or making changes to your care.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.