Dear Editor,
In a recent correspondence, Abdelrahman et al. (
Abdelrahman et al., 2022
) described the protective effect of parasites on COVID-19 as a myth rather than a reality (- Abdelrahman M.Makram
- Alied Marcel
- Khan Zeeshan Ali
- Huy Nguyen Tien
Parasites Protect from Severe COVID-19. Myth or Reality?.
Int J Infect Dis. 2022; (March 21 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2022.03.027
Bamorovat et al., 2021
; - Bamorovat M
- Sharifi I
- Aflatoonian MR
- Karamoozian A
- Tahmouresi A
- Jafarzadeh A
- et al.
Prophylactic effect of cutaneous leishmaniasis against COVID-19: A case-control field assessment.
Int J Infect Dis. 2021; (Sep 24 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2021.09.050
Wolday et al., 2021a
). In addition, they indicated that a study (Abdoli, 2020
) has found that parasitic infections, like helminths, increase the risk of COVID-19 severity.Concerning our study (
Wolday et al., 2021a
), they noted that intestinal parasitic co-infection was attributed to having less COVID-19 complications. This is an incorrect interpretation because we in fact demonstrated that less COVID-19 complications were attributed to having pre-existing co-infections with parasites and not vice versa. They incorrectly suggested that the probability of inclusion is associated with COVID-19 exposure and outcome (proportion of parasite co-infection). This is not the case because in our study, we defined exposure as having pre-existing parasite co-infection and outcome as the proportion of developing severe COVID-19. Moreover, admission bias in our cohort was minimal owing to the unique situation of our setting where all COVID-19 cases were followed up, either quarantined in designated isolation hospitals or admitted to the intensive care unit (Abraha et al., 2021
; Wolday et al., 2021a
).Surprisingly, Abdelrahman et al. (
Abdelrahman et al., 2022
) also incorrectly construed the publication by - Abdelrahman M.Makram
- Alied Marcel
- Khan Zeeshan Ali
- Huy Nguyen Tien
Parasites Protect from Severe COVID-19. Myth or Reality?.
Int J Infect Dis. 2022; (March 21 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2022.03.027
Abdoli, 2020
. A more careful review of this study reveals a hypothesis that helminths may increase severity of COVID-19 and also may suppress the immune response to SARS-CoV-2 vaccines but evidence was not provided. In contrast, our findings provide significant correlative evidence embedded in a sound immunologic theory. Indeed, Bradbury et al., 2020
were the first to propose that helminths may negatively impact the pathogenesis of COVID-19. An alternative hypothesis was then suggested by Hayes et al. (Hays et al., 2020
) that co-infection with helminths may indeed have a mitigating effect against severe COVID-19. Given that parasites have complex inter-relationships with a host and that different species and even different stages of parasite life cycle exerting differential immune responses in the host, we and others argued that parasitic co-infections could be either beneficial or detrimental to COVID-19 severity or their effects on SARS-CoV-2 vaccines (Gutman et al., 2020
; Wolday et al., 2021b
, Wolday et al., 2021c
).We suggest that before concluding that co-infection with parasitic infection in reducing COVID-19 severity as being a myth, it is imperative to provide evidence. Finally, we agree with Abdelrahman et al. (
Abdelrahman et al., 2022
) that more evidence is required to ascertain in detail the causal relationship between parasitic infection and COVID-19 severity.- Abdelrahman M.Makram
- Alied Marcel
- Khan Zeeshan Ali
- Huy Nguyen Tien
Parasites Protect from Severe COVID-19. Myth or Reality?.
Int J Infect Dis. 2022; (March 21 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2022.03.027
Declarations Conflict of interest
DW is a senior research fellow of the European and Developing Countries Clinical Trials Partnership and receives funding from European and Developing Countries Clinical Trials Partnership for the projects EvaLAMP and Profile-Cov and serves as a part of the Strategic and Scientific Advisory Board of the Research Networks for Health Innovations in Sub-Saharan Africa (German Federal Ministry of Education and Research). TRW is an employee of the not-for-profit PharmAccess Foundation, a board member of Mondial Diagnostics, and aScientific Advisory Board member of Health Inc., Netherlands.
Funding
None.
Ethical consideration
Not applicable.
References
- Parasites Protect from Severe COVID-19. Myth or Reality?.Int J Infect Dis. 2022; (March 21 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2022.03.027
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- Prophylactic effect of cutaneous leishmaniasis against COVID-19: A case-control field assessment.Int J Infect Dis. 2021; (Sep 24 [Epub ahead of print])https://doi.org/10.1016/j.ijid.2021.09.050
- Will helminth co-infection modulate COVID-19 severity in endemic regions?.Nat Rev Immunol. 2020; 20: 342
- Malaria and Parasitic Neglected Tropical Diseases: Potential Syndemics with COVID-19?.Am J Trop Med Hyg. 2020; 103: 572-577
- Helminth coinfection and COVID-19: an alternate hypothesis.PLoS Negl Trop Dis. 2020; 14: e0008628
- Effect of co-infection with parasites on COVID-19 severity: A prospective cohort study.eClinicalMedicine. 2021; 39: 101054
- Rinke deWit TF. Chronic Immune Activation and CD4+ T cell Lymphopenia in Healthy African Individuals: Perspectives for SARS-CoV-2 Vaccine Efficacy.Front Immunol. 2021; 12: 693269
- Interogating the impact of intestinal-microbiome on pathogenesis of COVID-19 in Sub-Saharan Africa.Front Microbiol. 2021; 12: 614522
Article info
Publication history
Published online: April 08, 2022
Accepted:
April 6,
2022
Received:
April 5,
2022
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