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\begin{document}

\title{The influence of ABO blood type on the severity of COVID-19}



\author[1]{Arif Yener}%
\affil[1]{Affiliation not available}%


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  \date{May 21, 2024}


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\textbf{The influence of ABO blood type on the severity of COVID-19}

\selectlanguage{ngerman}\emph{Arif Ülkü Yener\textsuperscript{1}}

\textsuperscript{1}Department of Ophthalmology, Keçiören Training and
Research Hospital, Ankara, Turkey

e-mail: arifulkuyener@hotmail.com

Orcid No: 0000-0002-0039-0438

\textbf{Letter to Editor}

In the study of I. Solmaz and S. Ataç published in your journal ``ABO
blood groups in COVID-19 patients; Cross-sectional study'', it was
determined that patients with blood group A are more susceptible to the
disease than those with blood group O, and the infection has no effect
on the prognosis of patients in intensive care unit (ICU). In our
report, in addition, the effect of the ABO blood type on patients
hospitalized in ICU on patients hospitalized in infectious diseases
clinic (IDC) was also compared.

It has been demonstrated that there is a relationship between the risk
of SARS-CoV infection and blood types, and that the blood group O has a
protective effect against SARS-CoV-1 and
SARS-CoV-2.\textsuperscript{1,2} In these studies, the authors observed
that the percentage of individuals with blood group O was significantly
lower amongst patients requiring hospitalization for severe COVID-19
infection, whereas blood group A was significantly more common in
patients compared to local population. As a result, blood group O has a
significant protective effect.\textsuperscript{2} Blood group antigens
can modify the innate immune response to
infection.\textsuperscript{3}Natural human anti-A antibodies might block
the interaction between SARS-CoV and its receptor, thereby providing
protection, which could explain why individuals with blood group A were
more susceptible to SARS-CoV-2 infection, while individuals with blood
group O were not.

It was found that the anti-A antibodies found in individuals with blood
group O inhibited the interaction of SARS-CoV-1 virus S spike protein
and the ACE-2 receptor.\textsuperscript{3} Multiple studies have shown
that ABO blood group is an important risk factor for cardiovascular
diseases and venous thromboembolism. The risk of thrombosis is
significantly reduced in blood group O compared to non-O individuals.
COVID-19 is associated with coagulopathy, and microthrombi disseminated
through the long vasculature contribute to
SARS-CoV-2.\textsuperscript{4} The association between ABO blood group
and COVID-19 susceptibility is of particular importance. ABO effects on
vonWillebrand factor (VWF)/FVIII and platelet biology play a major role
in determining the reduced risk of thrombosis observed in blood group O
subjects. Regarding the association of ABO blood group with COVID-19
sensitivity, it is important to note markedly elevated plasma VWF-Ag and
FVIII levels in patients with severe SARS-CoV-2
pneumonia.\textsuperscript{5}

In this report, the blood group of each patient was obtained from the
ABO blood type database. The medical records of 304 ICU and 1325 IDC
patients with COVID-19 were divided into 4 groups, A,B,O, and AB,
according to different ABO blood types. The ABO blood group distribution
of ICU patients was analyzed and compared with ABO blood group
distribution of IDC group. In addition, the results of patients who died
and survived in ICU were compared with chi-square and Fisher's exact
tests. The blood group A is the most common for both groups of patients,
followed by O, B, and AB blood types. Even though the percentages of all
blood types were not significantly different, blood group A showed a
higher frequency and blood group O a lower frequency for ICU patients (P
= 0.07 and 0.09, respectively) (Table 1). COVID-19 patients hospitalized
in IDC passed the disease moderately and symptoms were less severe
compared to ICU patients. This comparison revealed that the ABO blood
group has no effect on the severity of SARS-CoV-2 pneumonia.
Subsequently, the frequency of ICU patients who died or survived
according to ABO blood group was compared. Table1 represents that there
are no differences between the blood groups in respect of death or life.

\textbf{Keywords:} COVID-19, SARS-CoV-2, coronavirus disease, ABO blood
type

\emph{\textbf{Conflicts of interest} There are no conflicts of interest
in this report.}

\emph{\textbf{Acknowledgement} No funding support was used.}

\textbf{REFERENCES}

1. Cheng Y, Cheng G, Chui CH, et al. ABO blood group and susceptibility
to severe acute respiratory

syndrome. \emph{JAMA} 2005;293(12):1450-1451.

2. Li J, Wang X, Chen J, et al. Association between ABO blood group and
risk of SARS-CoV-2

pneumonia. \emph{Br J Haematol} 2020. doi: 10.1111/bjh.16797.

3. Cooling I. Blood groups in infection and host
susceptibility.\emph{Clin Microbiol} 2015;28(3):801-870.

4. McGonagle D, O'Donnell JS, Sharif K, et al. Immune mechanisms of
pulmonary intravascular

coagulopathy in COVID-19 pneumonia.\emph{Lancet Rheum} 2020,
doi:10.1016/S2665-9913(20)30121-1

5. Helms J, Severac F, Merdji H, et al. Prothrombotic phenotype in
COVID-19 severe patients.

\emph{Int Care Med} 2020. doi: 10.1007/s00134-020-06082-7.

\textbf{Hosted file}

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