Study findings updated . AI-assisted evidence summary, not individual medical advice or a clinician endorsement.
THE SHORT VERSION
What’s worth knowing.
The key findings, what they mean, and the context that matters.
THE HEADLINE TAKEAWAYAbout 50% in South Asiacarry the Neanderthal DNA linked to the top inherited risk; about 16% in Europe
The biggest inherited risk for severe COVID came from Neanderthals
Genetic studies comparing hospitalized COVID patients with controls found one stretch of DNA to be the major genetic risk factor for severe illness. This study traced that segment to Neanderthals, an extinct group of ancient humans whose DNA lives on in many people today. Around 50% of people in South Asia and around 16% of people in Europe carry it.
Part of why COVID hits some people harder may lie in ancient DNA, not just health or habits, and families with South Asian roots are especially likely to carry this stretch. A short genetic analysis of existing patient data and ancient genomes; it shows where the risk DNA came from and how common it is, not any one carrier's chance of severe illness.
See the evidence
A 2020 Nature analysis comparing the main COVID risk region, found in a study of 3,199 hospitalized patients and controls, with Neanderthal genomes and world population data.
From the study: “this cluster is the major genetic risk factor for severe symptoms after SARS-CoV-2 infection and hospitalization”
About 50% in South Asia
Zeberg H et al. The major genetic risk factor for severe COVID-19 is inherited from Neanderthals. Nature. 2020.
Interferon-blocking antibodies were found in 18% of people who died of COVID
18% of those who diedcarried interferon-blocking antibodies, in a sample of 1,124 patients who died
Some people make antibodies that disable their own type I interferons, proteins that raise the body's early alarm against viruses. These antibodies were found in 18% of 1,124 patients who died of COVID. Among uninfected adults, high-strength versions turned up in 0.18% of people between 18 and 69 years but 3.4% of those over 80, and the antibodies were present before infection.
These antibodies help explain why COVID risk climbs so steeply with age, and because they are present before infection, they can in principle be found ahead of time. International study of patients from 38 countries plus 34,159 uninfected adults; the 18% is the share among those who died, not any carrier's personal chance of dying.
See the evidence
An international study testing blood from 3,595 critically ill COVID patients, 1,124 who died and 34,159 uninfected people for anti-interferon antibodies, published in 2021.
From the study: “These antibodies are also detected in 18% of the 1,124 deceased patients”
18% of those who died
Bastard P et al. Autoantibodies neutralizing type I IFNs are present in ~ 4% of uninfected individuals over 70 years old and account for ~ 20% of COVID-19 deaths. Science immunology. 2021.
From the study: “auto-Abs neutralizing high concentrations of IFN-α and/or -ω are present in 0.18% of individuals between 18 and 69 years, 1.1% between 70 and 79 years, and 3.4% >80 years”
18% of those who died
Bastard P et al. Autoantibodies neutralizing type I IFNs are present in ~ 4% of uninfected individuals over 70 years old and account for ~ 20% of COVID-19 deaths. Science immunology. 2021.
From the study: “Auto-Abs neutralizing type I IFNs predate SARS-CoV-2 infection and sharply increase in prevalence after the age of 70 years.”
18% of those who died
Bastard P et al. Autoantibodies neutralizing type I IFNs are present in ~ 4% of uninfected individuals over 70 years old and account for ~ 20% of COVID-19 deaths. Science immunology. 2021.
1 in 9 hospitalized kids with COVID pneumonia had inherited immune defects
1 in 9 childrenhospitalized with COVID-19 pneumonia had a recessive immune gene defect (12 of 112)
In an international group of 112 children under 16 hospitalized for COVID-19 pneumonia, 12 (10.7%), aged 1.5 to 13, had a recessive (no working copy) inherited defect in type I interferon, the body's early antiviral alarm. Seven had TLR7 deficiency, a defect on the X chromosome. None of 1,224 children and adults with mild infection without pneumonia had any of these defects.
When a child becomes very sick with COVID, an inherited immune weakness may lie behind it, which can matter for brothers, sisters and relatives who share the same genes. Small international study of children from 14 countries, with older controls on average; the roughly 10% figure applies only to children sick enough to be hospitalized.
See the evidence
An international genetic study sequencing 112 children hospitalized for COVID pneumonia and 1,224 mildly infected children and adults, published in 2022.
From the study: “In an international cohort of 112 children (<16 yr old) hospitalized for COVID-19 pneumonia, we report 12 children (10.7%) aged 1.5-13 yr”
1 in 9 children
Zhang Q et al. Recessive inborn errors of type I IFN immunity in children with COVID-19 pneumonia. The Journal of experimental medicine. 2022.
Younger carriers had steeper odds of death or severe respiratory failure
2.7× higher oddsodds ratio for death or severe respiratory failure, carriers age 60 years and younger
Among COVID patients, carriers of the major common genetic risk variant had higher odds of death or severe respiratory failure than non-carriers. The odds were 2.7 times higher for carriers age 60 years and younger, but 1.5 times for those more than 60 years. The variant predicted these outcomes about as well as, or better than, most established clinical risk factors.
Severe COVID in a younger adult without obvious risk factors may partly reflect inherited DNA, and a single genetic marker can add real information when weighing someone's risk. Observational pooled data from 13,888 COVID patients in 17 cohorts across 9 countries; it shows a link, not cause, and compares patients only with other patients.
See the evidence
A pooled analysis of DNA and records from 13,888 COVID patients, 7,185 of them hospitalized, in 17 cohorts across 9 countries, published in 2021.
From the study: “Risk allele carriers age 60 years and younger had higher odds of death or severe respiratory failure (OR, 2.7; 95% CI, 1.8-3.9)”
2.7× higher odds
Nakanishi T et al. Age-dependent impact of the major common genetic risk factor for COVID-19 on severity and mortality. The Journal of clinical investigation. 2021.
From the study: “compared with those of more than 60 years (OR, 1.5; 95% CI, 1.2-1.8; interaction, P = 0.038)”
2.7× higher odds
Nakanishi T et al. Age-dependent impact of the major common genetic risk factor for COVID-19 on severity and mortality. The Journal of clinical investigation. 2021.
From the study: “This risk variant improved the prediction of death or severe respiratory failure similarly to, or better than, most established clinical risk factors.”
2.7× higher odds
Nakanishi T et al. Age-dependent impact of the major common genetic risk factor for COVID-19 on severity and mortality. The Journal of clinical investigation. 2021.
Scan of 24,202 critically ill patients found 49 signals, including drug targets
49 genetic signalslinked to critical illness in 24,202 patients; one gene clue led to testing baricitinib
Comparing 24,202 critically ill COVID-19 patients with population controls, researchers found 49 genetic signals, 16 of them new, several in genes that existing drugs can target. An earlier signal from this project led directly to testing baricitinib, an immune-calming drug called a JAK inhibitor, in a large clinical trial, which showed a clear benefit.
Studying the DNA of the sickest patients pointed to a treatment that worked, and the other drug targets it flagged give researchers new leads to test. A genetic association study limited to common variants; most drug targets it names are predictions, and the authors say further research is needed to confirm them.
See the evidence
A 2023 genome-wide study of 24,202 critically ill COVID patients from the GenOMICC, ISARIC4C and SCOURGE studies, combined with earlier published data.
From the study: “Here we analyse 24,202 cases of COVID-19 with critical illness”
49 genetic signals
Pairo-Castineira E et al. GWAS and meta-analysis identifies 49 genetic variants underlying critical COVID-19. Nature. 2023.
From the study: “led directly to the inclusion of a new drug, baricitinib, in a large clinical trial; the result demonstrated a clear therapeutic benefit”
49 genetic signals
Pairo-Castineira E et al. GWAS and meta-analysis identifies 49 genetic variants underlying critical COVID-19. Nature. 2023.
A variant near lung gene FOXP4 was linked to long COVID
63% higher oddsof long COVID linked to a variant near FOXP4, a lung-related gene (odds ratio 1.63)
Comparing people with long COVID against population controls, researchers found one clear genetic signal: a variant near FOXP4, a gene involved in lung function. It was linked to 63% higher odds of long COVID (odds ratio 1.63), and the signal held up in independent groups. The variant's frequency ranges from 1.6% in non-Finnish Europeans to 36% in East Asians.
One variant cannot tell any individual whether they will get long COVID, but it points researchers toward lung biology as a place to look for answers. Observational genetic study of up to 6,450 cases across 16 countries, mostly of European ancestry; replication estimates were smaller than the discovery estimate, and case definitions varied.
See the evidence
A 2025 genome-wide study pooling 24 studies in 16 countries, with up to 6,450 long COVID cases and 1,093,995 controls, replicated in further groups including the VA Million Veteran Program.
From the study: “The C allele at rs9367106 was associated with an increased risk of long COVID (odds ratio (OR) = 1.63, 95% confidence interval (CI) = 1.40–1.89, risk allele frequency = 4.2%).”
63% higher odds
Lammi V et al. Genome-wide association study of long COVID. Nature genetics. 2025.
A common immune gene type was linked to staying symptom-free
2.4× odds of no symptomsfor carriers of the immune gene type HLA-B*15:01 vs non-carriers (odds ratio 2.40)
Among 1,428 unvaccinated people who tested positive, those carrying HLA-B*15:01, a version of a gene that shows virus fragments to the immune system, had 2.4 times the odds of having no symptoms compared with non-carriers (odds ratio 2.40). About 10% of people with European ancestry carry it. The authors tie this to T cells, immune cells primed by common-cold coronaviruses, that already recognized the virus.
It offers one concrete reason some people never notice an infection: their immune system may arrive partly prepared, a clue that could guide vaccines that train T cells. Self-reported symptoms from unvaccinated bone-marrow registry volunteers who identified as white; it is observational and may not apply to other ancestries.
See the evidence
A smartphone symptom study of nearly 30,000 volunteer bone-marrow donors with known tissue types; 1,428 unvaccinated people who tested positive formed the main analysis.
From the study: “individuals carrying this common allele (approximately 10% in individuals with European ancestry) are more than twice as likely to remain asymptomatic”
2.4× odds of no symptoms
Augusto DG et al. A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection. Nature. 2023.
From the study: “a significant association of HLA-B*15:01 with asymptomatic infection after adjustment for these variables (OR = 2.40, 95% CI = 1.54–3.64”
2.4× odds of no symptoms
Augusto DG et al. A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection. Nature. 2023.
From the study: “Our final cohort comprised 1,428 individuals who reported a positive test for active SARS-CoV-2 infection and self-identified as white.”
2.4× odds of no symptoms
Augusto DG et al. A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection. Nature. 2023.
1 in 4 severe breakthrough cases carried interferon-blocking antibodies
1 in 4 breakthroughs10 of 42 severe cases with normal vaccine response had anti-interferon antibodies
Researchers studied people who received two doses of an mRNA vaccine yet developed hypoxemic (low-oxygen) COVID-19 pneumonia. Of 42 with a normal antibody response to the vaccine, 10 (24%) carried antibodies that disable type I interferons, an early antiviral alarm. None of the 10 patients died of COVID-19.
A normal vaccine antibody result does not guarantee protection from serious pneumonia for people with these antibodies, a group the authors call particularly vulnerable. Small case series of 48 vaccinated patients from 6 countries, likely during the Delta wave, with no comparison group; it cannot say how often carriers develop severe breakthroughs.
See the evidence
A study testing blood from 48 people with low-oxygen breakthrough COVID after two mRNA doses, recruited in six countries including the United States, before late 2021.
From the study: “who received two doses of a messenger RNA (mRNA) vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia”
1 in 4 breakthroughs
Bastard P et al. Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs. Science immunology. 2023.
From the study: “were found at the onset of disease in 10 of 42 patients (24%) with breakthrough COVID-19 who suffered from hypoxemic pneumonia, despite having a normal antibody response to an mRNA vaccine”
1 in 4 breakthroughs
Bastard P et al. Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs. Science immunology. 2023.
No persistent blood-methylation difference was detected between groups
No clear difference
Paired samples from 297 adults showed no significant persistent group differences in whole-blood DNA methylation or epigenetic-aging measurements.
The Long COVID, recovered and not-infected groups contributed 594 samples total, collected in 2020 and 2023. This assay-specific null does not rule out smaller effects or changes in other tissues.
Study details & original results
Bohlin, Jon et al.. Longitudinal study of genome-wide DNA methylation in individuals with and without post-acute symptoms following SARS-CoV-2 infection.. Epigenomics. 2026.
Persistent whole-blood DNA methylation and epigenetic-aging measurements in a longitudinal comparison of Long COVID, recovered COVID-19 and not-infected groups; paired samples from 297 adults (594 samples total) collected in 2020 and 2023.
No significant persistent group differences detected
The reported result does not establish a difference; it does not prove equivalence.
Dates show when findings were added here, not when papers were published. Study populations and comparisons differ.
WHEN YOU WANT TO GO DEEPERSee all 1 findingsOriginal results, comparisons and study details.
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SOURCE 011 finding
Bohlin, Jon et al.. Longitudinal study of genome-wide DNA methylation in individuals with and without post-acute symptoms following SARS-CoV-2 infection.. Epigenomics. 2026.
Persistent whole-blood DNA methylation and epigenetic-aging measurements in a longitudinal comparison of Long COVID, recovered COVID-19 and not-infected groups; paired samples from 297 adults (594 samples total) collected in 2020 and 2023.
Added
No significant persistent group differences detectedSource [1]
Browse the 9 original sourcesThe complete bibliography behind this monitor.
[1]
Bohlin, Jon et al.. Longitudinal study of genome-wide DNA methylation in individuals with and without post-acute symptoms following SARS-CoV-2 infection.. Epigenomics. 2026.
Bastard P et al. Autoantibodies neutralizing type I IFNs are present in ~ 4% of uninfected individuals over 70 years old and account for ~ 20% of COVID-19 deaths. Science immunology. 2021.
Nakanishi T et al. Age-dependent impact of the major common genetic risk factor for COVID-19 on severity and mortality. The Journal of clinical investigation. 2021.
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