Helminths may confer protection against COVID-19
Someone who contracts SARS-CoV-2 and develops COVID-19 may recover from the illness more quickly and face a reduced risk of fatality if they are hosting helminths.
Hookworm antigens are known to up-regulate genes belonging to certain families, including P53, that are responsible for programmed cell death.  In other research, it was found that P53 reduces replication of the SARS-CoV by 65%. 
The emerging science
- 2023 Aug 11 Exposure to lung-migrating helminth protects against murine SARS-CoV-2 infection through macrophage-dependent T cell activation
- These results demonstrate that lung-migrating helminths reprogram lung immune homeostasis, leading to enhanced protection against subsequent SARS-CoV-2 infection. (The species used in this research was Nippostrongylus brasiliensis, which is similar to Necator americanus, the hookworm used in helminthic therapy which is also a lung-migrating worm.)
- 2023 Jun 20 The Potential Nexus between Helminths and SARS-CoV-2 Infection: A Literature Review -- Full text | PDF
- … chronic helminth infections may reduce the severity of SARS-CoV-2 infection by reducing hyperinflammation and exaggerated immune response.
- 2023 May Immunological interactions in helminths-SARS CoV-2 coinfection: Could old enemy be a friend today?
- … COVID-19 severity in patients with chronic helminth infections (CHIs) is mild, as immuno-suppressive anti-inflammatory cytokines counterbalance the risk of cytokine storm. Here, an overview of the interplay between helminths and COVID-19 severity is given.
- 2023 Feb 9 COVID-19 morbidity in lower versus higher income populations underscores the need to restore lost biodiversity of eukaryotic symbionts | PDF
- … it is now apparent that 'biome reconstitution', defined as the artificial re-introduction of benign, symbiotic helminths or protists into the ecosystem of the human body, is important not only for alleviation of chronic immune disease, but likely also for pandemic preparedness.
- 2022 Nov 10 Helminth exposure protects against murine SARS-CoV-2 infection through macrophage dependent T cell activation -- Full text | PDF
- This study shows that lung remodelling from a prior helminth infection promotes recovery and less severe outcomes in mice challenged with SARS-CoV-2.
- 2022 Jun 28 Helminth antigens differentially modulate the activation of CD4 + and CD8 + T lymphocytes of convalescent COVID-19 patients in vitro -- Full text | PDF
- Our data offer a plausible explanation for the moderate incidence of COVID-19 in Africa and support the hypothesis that helper T cell-mediated immune responses to SARS-CoV-2 are mitigated in the presence of helminth antigens, while virus-specific cytotoxic T cell responses are maintained.
- 2022 Mar Immunomodulation of COVID-19 severity by helminth co-infection: Implications for COVID-19 vaccine efficacy -- Full text | PDF
- We argue that helminth-derived products and molecules that can potentially induce a Th2-biased immune response may provide a contributory role in preventing severe COVID-19 by restricting the cytokine storm associated with ARDS… Another unanswered question is whether a well-controlled low level concomitant infection with a live helminth, such as hookworm, can achieve an equivalent or superior effect to an immunomodulator or vaccine in preventing serious outcomes of COVID-19. It would be valuable to test such helminthic-based therapies as these may represent a safe and cost-effective anti-inflammation approach to reducing COVID-19 severity.
- 2022 Jan 19 Helminths and COVID-19 susceptibility, disease progression, and vaccination efficacy -- Full text
- We postulate that helminth infection may be beneficial in preventing cytokine storms and severe COVID-19…
- 2021 Dec 6 Evolutionary medicine helps explain pandemic dynamics: Predictions regarding clinical impact of COVID-19 borne out
- A significant amount of the tragic clinical outcome of the COVID pandemic in high-income countries might arguably have been mitigated had timely investigations been carried out into the effects of the loss of helminths and protists in these countries and into the reintroduction of benign species capable of safely modulating immune function.
- 2021 Oct 27 The Influence of Helminth Immune Regulation on COVID-19 Clinical Outcomes: Is it Beneficial or Detrimental? — Full text | PDF
- The authors call for more studies looking at pre-existing helminth and SARS-CoV-2 co-infection, with a view to informing the management of COVID-19 in areas where helminth infections are co-endemic.
- 2021 Oct 26 Helminth infection is associated with dampened cytokine responses to viral and bacterial stimulations in Tsimane forager-horticulturalists -- Full text | PDF
- The results support the hypothesis that soil-transmitted helminths inhibit the cytokine response to viruses and bacteria by dampening the proinflammatory cytokine phenotype, suggesting that the helminth-induced anti-inflammatory immunomodulatory network may attenuate some of the most severe symptoms of viral infections such as SARS-CoV-2.
- 2021 Sept Effect of co-infection with intestinal parasites on COVID-19 severity: A prospective observational cohort study -- Full text | PDF
- This study showed a significant inverse correlation between the presence of intestinal parasites and COVID-19 severity, suggesting that parasite co-infection, with both protozoa and helminths, may protect against progression to severe COVID-19.
- A growing body of studies suggests COVID-19 emulates many aspects of systemic autoimmune disorders, including the release of a flurry of overactive immune cells that produce toxic webs of proteins and DNA called neutrophil extracellular traps, or NETs.
- Therapeutic administration of helminth excretory/secretory factors has been shown to modulate these neutrophil responses, abolishing NET formation and reducing the ensuing inflammation. 
- 2021 Jul 19 Gut Microbiota Diversity and C-Reactive Protein Are Predictors of Disease Severity in COVID-19 Patients
- This study demonstrated that hospitalized patients with moderate and severe COVID-19 have microbial signatures of gut dysbiosis. Since helminths are known to engender beneficial changes in the gut microbiota  this study’s findings may suggest a beneficial role for helminths in reducing COVID-19 severity.
- 2021 Jul 16 Patterns of SARS-CoV-2 exposure and mortality suggest endemic infections, in addition to space and population factors, shape dynamics across countries
- The number of SARS-CoV-2 cases was not the only predictor of deaths, with countries with a high prevalence of hookworm and malaria experiencing fewer SARS-CoV-2 deaths compared to those with lower hookworm and malaria prevalence.
- 2021 Jun 15 SARS-CoV-2 and helminth co-infections, and environmental pollution exposure: An epidemiological and immunological perspective -- Full text | PDF
- The present review focused on the epidemiology of SARS-CoV-2, helminths and fine particulate matter air pollution exposure in helminth endemic regions, the possible immunomodulatory activity of helminths against SARS-CoV-2 hyper-inflammatory immune response, and whether air and water pollutants can further exacerbate SARS-CoV-2 related cytokine storm and in the process hinder helminths immunomodulatory functionality.
- 2021 Jun 7 The New Status of Parasitic Diseases in the COVID-19 Pandemic—Risk Factors or Protective Agents? — Full text
- Reviews current knowledge about the relationships between a wide range of parasitic infections and COVID-19.
- 2021 May 26 Emerging issues in COVID-19 vaccination in Tropical Areas: Impact of the Immune Response against Helminths in Endemic Areas
- The implications of the immunomodulation effect of helminths in endemic areas must be considered in the context of COVID-19 mass vaccination.
- It is essential to remember the manifold negative effects of intestinal parasitosis... In regions where undernutrition rather than overnutrition is a dominating concern, nutritional and metabolic compromise may present a greater hazard in persons at risk for SARS-CoV-2 infection.
- 2021 Apr 16 Interrogating the Impact of Intestinal Parasite-Microbiome on Pathogenesis of COVID-19 in Sub-Saharan Africa -- Full text | PDF
- Here, we propose that the interplay between intestinal parasites and microbiome may have a potential direct or indirect effects on the pathogenesis of SARS-CoV-2 infection, in particular in the context of Low- and Middle-Income Countries.
- 2021 Feb 12 Between a hygiene rock and a hygienic hard place: Avoiding SARS-CoV-2 while needing environmental exposures for immunity — Full text | PDF
- Evidence not only points to humans’ need of helminths for effective immune function, but also for an effective immune response against SARS-CoV-2 and other viral infections.
- 2021 Feb 2 Effect of co-infection with parasites on severity of COVID-19 -- PDF (medRxiv preprints)
- Pre-existing infection with either protozoan parasites or helminths appears to be associated with reduced COVID-19 severity.
- (Related media article: Research shows intestinal parasite infestations reduce COVID-19 severity - Liji Thomas, News Medical)
- 2020 Oct 20 Old Friends Meet a New Foe – A potential role for immune-priming parasites in mitigating COVID-19 morbidity and mortality -- Full text | PDF
- An evolutionary perspective is required to understand the global impact and various presentations of COVID-19. We consider how coinfection with soil-transmitted helminths (common parasitic worms that coevolved with humans) may suppress inflammatory immune activity, thereby potentially reducing COVID-19 disease severity.
- (Related media article: Cepon-Robins illustrates how immune responses to intestinal parasites could reduce severity of COVID-19 - Anna Squires, Communique.)
- 2020 Oct 15 Potential Influence of Helminth Molecules on COVID-19 Pathology -- Full text | PDF
- Helminth parasites could change the outcome of COVID-19 infections, in areas of the world where helminthic infections are still prevalent, by inducing a modified Th2 response with a controlled inflammatory component. Notably, in countries of Africa and Latin America, where helminth infections are still common, the numbers of reported COVID-19 deaths are substantially lower than those reported in high-income countries.
- 2020 Oct 8 COVID-19 Lethality in Sub-Saharan Africa and Helminth Immune Modulation -- Full text | PDF
- … we argue that helminth coinfection… may be related to the low lethality of COVID-19 in Sub-Saharan Africa.
- The hygiene hypothesis, which posited that children exposed to certain environments and enteric organisms such as helminths were less likely to develop allergies and autoimmune diseases than those who experienced a more hygienic upbringing, may apply to COVID-19 susceptibility and severity.
- 2020 Aug 17 Helminth coinfection and COVID-19: An alternate hypothesis -- Full text | PDF
- We believe… that any interaction between pre-existing helminth infection and the subsequent severity of COVID-19 need not necessarily be a negative one, and theoretical and empirical evidence suggests that helminths may indeed have a mitigating effect.
- Our main hypothesis therefore is that chronic helminth infection, and the immune consequences thereof, is the main reason why the Covid-19 pandemic have a relatively much lower presence in the millenarian global helminth belt than in the modern urban "dewormed" world...
- 2020 May 18 Parasites and their protection against COVID-19- Ecology or Immunology? (PDF)
- We report a consistent inverse correlation between the incidence of COVID-19 and parasitic infections observed across WHO regions. These preliminary findings from an ecological analysis, support our hypothesis of a possible immune-modulatory mechanism induced by parasitic infections, which is protective against COVID-19 and warrants further investigation.
- 2020 May 15 Immunity, parasites, genetics and sex hormones: contributors to mild inflammatory responses in COVID-19? -- Full text | PDF
- Explores the possible factors, including parasites, that may be contributing to the lower number of COVID-19 deaths reported in Africa.
- 2020 May 1 Will helminth co-infection modulate COVID-19 severity in endemic regions? -- Full text | PDF
- We call on the research community to investigate the influence of helminth co-infection on COVID-19 outcomes as the pandemic spreads through the helminth-endemic regions of the word. Potential negative effects may influence recommendations on deworming.
- 2020 Apr 27 Asthma and COVID-19: The Eosinophilic Link
- Finally, we could also speculate that the high prevalence of parasitic diseases and therefore the pervasiveness of (blood or tissue) eosinophilia and the relatively low incidence of the (COVID-19) pandemic in areas like Tropical Africa or the Indian subcontinent, could be somehow linked. Only time and further research will tell us if there is a relevant connection here.
- 2017 Oct Enteric helminth-induced type I interferon signaling protects against pulmonary virus infection through interaction with the microbiota -- Full text | PDF
- In conclusion, we show that intestinal helminth infection can be beneficial in viral respiratory tract infections… we hypothesize that helminth infection in the gut triggers type I interferon production through bacterial interactions, which leads to systemic type I interferon induction, thus raising preparedness of remote sites, such as the lung, to mount an effective innate response against incoming unrelated viral pathogens.
The experience of Brazil
Brazil has been one of the countries most severely affected by the pandemic, with SARS-CoV-2 spreading particularly rapidly in the pandemic’s early stages in Maranhao State in the Northeast region of the country. However, this state’s fatality rate peaked in May and fell consistently thereafter. 
By April 2021, Maranhao State had Brazil’s lowest covid-19 caseload (9 per 100,000) and almost the lowest death rate (0.61 per 100,000) per population. 
Researchers reporting from Maranhao in September 2020 had estimated that the prevalence of detectable antibodies (seroprevalence) in the state was already the highest, and the closest reported at that point to the herd immunity threshold,  in spite of the population’s generally low economic and nutritional status.
Soil-transmitted helminths (STH) are still endemic in Brazil’s Northeast region,  and a national survey carried out in 2016 had found the region’s highest STH prevalence was in Maranhao State, which also had the highest hookworm rate in Brazil. 
The experience among helminthic therapy self-treaters
Reactions to COVID-19
There have been very few reports from self-treaters describing the experience of COVID-19. Most comments from those in this community have described how they began to show signs of what appeared to be a viral infection but which soon resolved, or followed a course very similar to that of a bout of influenza, leaving most of these individuals uncertain as to whether they had had COVID-19 or not. The marked absence from this community of reports of severe illness attributed to COVID-19 may, itself, be suggestive of a beneficial role for helminths.
Someone who uses TSO to keep his ulcerative colitis in remission was able to weather a bout of the diarrhea-causing Xibalba COVID variant without it exacerbating his intestinal disease.
I began feeling ill on Day 2. I had a bout of intense diarrhea for one day - reminiscent of colitis of course - followed with fever. My wife suggested I do a Covid test. I agreed but I was certain it was a reaction caused by lots of unusual foods including gluten foods which I avoid at home. The test came out positive! We got the Xibalba Covid variant which is common now in the Yucatan peninsula. That variant is known to affect the intestinal tract and provoke diarrhea.
For 5 days I was ill with fever, cough, loss of smell, skin sensitivities etc. My intestines were hurting, my stools had mucus in them. I came back home to Canada testing negative but with my intestines still dysfunctional. The inflammation created pressure on my lower back and I have been feeling pain for several days.One week later, while it is not entirely resolved at this time, I feel 95% OK. I realized today that in spite of the Covid and its effect on my fragile intestinal tract, at no time I had blood in my stool and no sense of urgency either. In other words, it held well and I seem to do no worse than others with this variant. It did NOT trigger Ulcerative Colitis (which was my biggest fear), so all is well. 
Reactions to a COVID-19 vaccine
Several members of the helminthic therapy self-treatment community have reported significant health issues following receipt of COVID-19 vaccines.
- Someone working in an educational institution has reported that he was pressured by his employer into getting a COVID vaccine, which he described as a standard “virus plus aluminum adjuvant” version rather than an mRNA one. He had expressed concerns to his institution’s doctor about possible adverse effects from the vaccine, and requested exemption based on his history of autoimmune issues, and his concern about “rocking the boat” with his health, which had been much more stable since hosting helminths. He also referenced his experience with influenza, which he had always coped with well, unlike some others he knew who had had a flu vaccine. However, the institution’s medic had dismissed all his concerns and expressed total confidence in the safety of the vaccine, which the individual reluctantly accepted.
- After getting the vaccine, he experienced what he has described as “some scary autoimmune symptoms” and was still having difficulty getting his health back on track, in spite of hosting helminths, 6 months later.
- I've been struggling with a severe vax reaction the past 6 months with which my existing NA colony of maybe around 40, plus 2 top-ups of 20 (one 20 weeks ago, one 8) have seemingly not helped much. 
- And even at 9 months post vaccination.
- Still having problems with vax side effects 9 months after one dose of Sinovac. 
- Someone else has reported significant issues following the Moderna vaccine.
- I developed my first autoimmune disease shortly after my 2 shot Moderna shot. I went into remission 9 months later after changing my diet and practicing intermittent fasting. After my booster shot, I developed 2 more autoimmune diseases and the first one came back. Itis diet seems to be helping and I have high hopes for NA (but currently on day 6 with HT). 
- And a third helminthic therapy self-treater has reported a possible adverse effect following vaccination.
- My health has been declining slowly since April, which is coincidentally when I got vaccinated. Other variables are at play, so I definitely can't say with confidence that it's the vaccine that's caused it. It's just a tad confusing/disconcerting that I've had two (helminth) inoculations since April, but things seem to continue trending worse. 
Timing of vaccine doses and helminth inoculations
Treating COVID-19 while hosting helminths
Anyone hosting helminths who does develop this illness will want to use therapies that will not have any detrimental effect on their helminth colony. A comprehensive list of effective, helminth-friendly, natural antiviral therapies can be found here.
Can the corticosteroids used to treat COVID-19 cause helminth colonies to increase?
There have been several reports of Strongyloides stercoralis hyperinfection in COVID-19 patients treated with corticosteroids.      However, while this particular nematode species is of special concern in immunosuppressed persons due to the possibility of potentially life-threatening systemic hyperinfection,   TSO, TTO, HDC and NA do not present the same risk due to their inability to multiply within a host.
Can the mRNA and spike proteins from COVID vaccines pass into hookworm larvae?
This question, which was asked in the Helminthic Therapy Support group,  appeared to have arisen as a result of concern about the possibility of the vaccine mRNA or reverse transcribed spike protein DNA persisting in the cells of human vaccinees - a fiercely debated issue. The concern in the mind of the NA self-treater who asked the question was perhaps about whether any spike protein genetic material in the blood ingested by a hookworm might then be integrated into that worm’s genome, and passed, first, to the worm’s progeny, and then to their next human host, where it might be integrated into that host’s genome.
This possibility is thought to be vanishingly improbable because, firstly, the blood ingested by an adult hookworm will be broken down by the digestive enzymes and microbiota of the worm’s gut. And, secondly, because, even if an intact strand of the spike protein gene were to survive the digestive process, it would need to be absorbed, and then - the toughest challenge of all - would need to get into the worm’s ovary or testis, and into the chromosome of a germ cell. And this exceedingly improbable journey would need to be followed by another, in which a gene in the new generation of hookworms would need to be transmitted to the next human host.
This is therefore not something that hookworm self-treaters need to worry about. 
Helminthic therapy and Long COVID
Since Long COVID has many similarities with ME/CFS, also see Helminthic therapy and ME/CFS.
Using helminths to treat long COVID
One hookworm user who has reported that introducing 3 NA had very quickly led to full remission from their "pretty severe", ME/CFS-related post-exertional malaise, has said that this therapy also worked for them on Long COVID.
Another NA user reported a similar success with Long COVID.
And an HDC user has reported as follows.
Treating long COVID while hosting helminths
Treatment protocols have been, and are continuing to be, developed to address Long COVID, for example, those mentioned below.
However, care should be taken if using Long COVID treatment protocols while hosting helminths because these can include the use of anthelmintics such as ivermectin, which may obviously have a potentially harmful effect on therapeutic worms.