Helminthic therapy and COVID-19
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
- 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.
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
So far, there have been very few reports from members of the global community of helminthic therapy 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 over 60,000 members of reports of severe illness attributed to COVID-19 may, itself, be suggestive of a beneficial role for helminths.
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.